Papers for Tuesday, Nov 04 2025

Mass estimates of white dwarfs via electromagnetic methods, often differ from those obtained through gravitational redshift measurements, in some cases with discrepancies ranging in $5-15\%$ across independent datasets. Although many of the discrepancies reported in large spectroscopic surveys and confirmed by high-precision techniques such as astrometric microlensing and wide-binary analyses may be attributable to thermal effects, model uncertainties or measurement errors prevent a complete description of some of the observations. Here, we explore an alternative explanation based on the presence of a gravitationally coupled bosonic scalar field that contributes to the stellar mass while remaining electromagnetically invisible. We construct stationary, static mixed configurations consisting of a white dwarf that presents a bosonic scalar field (dark matter) component, forming a composite white dwarf-boson star system. We explore families of solutions showing that a scalar field fraction $f_{\rm DM} \sim 5-15\%$ to the mass contribution can account for the observed redshift excess. Our models provide a physically motivated explanation for the mass bias, might offer new observational signatures, and allow us to place preliminary constraints on the mass and compactness of the scalar field configuration. Finally, using our theoretical framework in combination with Bayesian model selection we provide plausible bounds for the mass of the constituent (ultralight) bosonic particle.

The Gaia mission has observed over 2 billion stars repeatedly across the entire sky over 10 years, revealing the many astronomical objects that vary on human timescales from seconds to years. Its repeated astrometric, photometric, spectrophotometric and spectroscopic measurements create an unprecedented dataset to probe the variable celestial sources down to G ~ 21 mag. To extract meaningful results from these many time series for so many sources, we have used machine learning techniques for crossmatching, variability detection, and variability classification. This approach has now led to the largest catalogue of classified variable sources ever produced over the entire celestial sphere.

Ground-based astronomical observations will continue to produce resolution-limited images due to atmospheric seeing. Deconvolution reverses such effects and thus can benefit extracted science in multifaceted ways. We apply the Scaled Gradient Projection (SGP) algorithm for the single-band deconvolution of several observed images from the Zwicky Transient Facility and mainly discuss the performance on stellar sources. The method shows good photometric flux preservation, which deteriorates for fainter sources but significantly reduces flux uncertainties even for the faintest sources. Deconvolved sources have a well-defined Full-Width-at-Half-Maximum (FWHM) of roughly one pixel (one arcsecond for ZTF) regardless of the observed seeing. Detection after deconvolution results in catalogs with $\gtrsim$99.6% completeness relative to detections in the observed images. A few observed sources that could not be detected in the deconvolved image are found near saturated sources, whereas for others, the deconvolved counterparts are detected when slightly different detection parameters are used. The deconvolution reveals new faint sources previously undetectable, which are confirmed by crossmatching with the deeper DESI Legacy DR10 and with Pan-STARRS1 through forced photometry. The method could identify examples of serendipitous potential deblends that exceeded SExtractor's deblending capabilities, with as extreme as $\Delta m \approx 3$ and separations as small as one arcsecond between the deblended components. Our survey-agnostic approach is better and eight times faster than Richardson-Lucy deconvolution and could be a reliable method for incorporation into survey pipelines.

Gaia observations have reignited interest in the optical and ultraviolet (UV) opacity problems of cool white dwarfs ($T_{\rm eff} \leq 6000$ K), which were thought to be resolved nearly two decades ago through the inclusion of Lyman $\alpha$ red wing opacity arising from H-H$_2$ collisions in atmospheric models. Recent studies have revealed that their masses derived from Gaia optical photometry are 0.1$-$0.2 M$_{\odot}$ lower than expected from single-star evolution. Since the Ly $\alpha$ H-H$_2$ wing opacity significantly affects the blue end of their optical spectra, it may contribute to the mass discrepancy. To investigate this hypothesis, we revisited the Ly $\alpha$ opacity calculations in the quasi-static single and multi-perturber approximations by explicitly using the ab initio potential energy data of H$_3$ while fully accounting for the H-H$_2$ collision angle. We find that the opacity is slightly smaller than the standard models at the shortest wavelengths ($\leq5000$ angstrom), but larger at longer wavelengths. Comparing synthetic magnitudes (GALEX, Gaia, WISE) to the observations of the 40 pc white dwarf sample, we note that the revised models tentatively reproduce the observed $NUV-G$ colours for stars cooler than 6000 K, but still fail to match $G_{\rm BP} - G_{\rm RP}$ colours, resulting in similarly low inferred masses ($\leq 0.5$ M$_{\odot}$) as obtained with the standard Ly $\alpha$ opacity. Exploring other dominant opacity sources, we discover that decreasing the strength of the bound-free H$^-$ opacity in existing models better reproduces the optical and infrared colours, while collision-induced absorption (CIA) opacity is ineffective in resolving the low-mass problem. We highlight the need for improved opacities and multi-wavelength observations in future studies.

Atomic Hydrogen (HI) is an important component of gas in and around galaxies and forms extended disk-like structures well beyond the extent of starlight. Here we investigate the properties and evolution of extended HI disks that emerge in six Milky Way-mass galaxies using cosmological zoom-in simulations from the Figuring Out Gas & Galaxies in Enzo (FOGGIE) suite. We focus on the formation, evolution, and morphology of extended gaseous disks that emerge in all six systems. We find that median HI column densities drop sharply at the disk edge, with mean column densities outside the disk dominated by dense (NHI~10^19 cm-2), clumpy structures. All systems have significant misaligned features (warps or polar rings) at some point in their evolution; however, their frequencies, lifetimes, and origins vary significantly. We find that the morphology of the FOGGIE disks are correlated with properties of their Circumgalactic Medium (CGM). We classify these systems into two broad categories: those with CGMs that are Less Populated with HI and those with CGMs that are More Populated with HI. Both categories kinematically settle by z=0, but the Less Populated systems all form thin disks by z=0, while the More Populated systems do not. This classification is independent of disk and halo mass, implying the formation of a thin disk is influenced by local environmental factors. Our results indicate a connection between CGM content and disk formation that is not yet fully understood. A second paper investigates observational aspects of these structures.

Atomic Hydrogen (HI) is a useful tracer of gas in and around galaxies, and can be found in extended disk-like structures well beyond a system's optical extent. Here we investigate the properties of extended HI disks that emerge in six Milky Way-mass galaxies using cosmological zoom-in simulations from the Figuring Out Gas & Galaxies in Enzo (FOGGIE) suite. This paper focuses on the observability of the extended HI in these systems. We find overall agreement with observational constraints on the HI size-mass relation. To facilitate direct comparisons with observations, we present synthetic HI 21-cm emission cubes. By spatially filtering our synthetic cubes to mimic the absence of short baselines in interferometric maps, we find that such observations can miss ~10-40% of diffuse emission, which preferentially removes low column density, low velocity dispersion gas outside the central disk. The amount of observable material depends strongly on its distribution and the system's observed orientation, preventing the formulation of a simple correction factor. Therefore, to fully characterize extended disks, their circumgalactic mediums, and the interfaces between them, dual convolutions including data from interferometers and large single-dish radio telescopes are required.

With the arrival of ever higher throughput wide-field surveys and a multitude of multi-messenger and multi-wavelength instruments to complement them, software capable of harnessing these associated data streams is urgently required. To meet these needs, a number of community supported alert brokers have been built, currently focused on processing of Zwicky Transient Facility (ZTF; $\sim 10^5$-$10^6$ alerts per night) with an eye towards Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST; $\sim 2 \times 10^7$ alerts per night). Building upon the system that successfully ran in production for ZTF's first seven years of operation, we introduce BOOM (Burst & Outburst Observations Monitor), an analysis framework focused on real-time, joint brokering of these alert streams. BOOM harnesses the performance of a Rust-based software stack relying on a non-relational MongoDB database combined with a Valkey in-memory processing queue and a Kafka cluster for message sharing. With this system, we demonstrate feature parity with the existing ZTF system with a throughput $\sim 8 \times$ higher. We describe the workflow that enables the real-time processing as well as the results with custom filters we have built to demonstrate the system's capabilities. In conclusion, we present the development roadmap for both BOOM and Babamul - the public-facing LSST alert broker built atop BOOM - as we begin the Rubin era.

The StarDICE experiment seeks to establish a metrology chain linking laboratory standards to astrophysical fluxes, targeting 1 mmag accuracy in the $\textit{griz}$ bands. Reaching this precision requires mitigating variable atmospheric effects, especially gray extinction from clouds, which remains a major challenge. To address this challenge, we present a novel method for correcting photometric data using simultaneous radiometric measurements from an infrared thermal camera. The gray extinction correction model is fitted on an image-by-image basis as a function of thermal radiance excess and difference between synthetic and instrumental fluxes of calibration stars. This approach stands out by avoiding any assumptions about spatial structure and leveraging a forward model combining in situ environmental monitoring, radiative transfer simulations and use of Gaia Data Release 3 star catalogs. We demonstrate the method using data collected from a dedicated experimental remote observation system, built to conduct repeated observations of two fields over several nights in varying atmosphere conditions. We show that applying the correction model to each source in the test sample results in a reduction of residuals between corrected and reference magnitudes. It delivers extinction correction maps for individual images with a resolution of 2 arcmin and an accuracy of $\sim$0.01 mag. This leads to a significant improvement in accuracy per image, with the mean absolute error decreasing from 0.64 to 0.11 mag for the most gray extinguished exposures. The temporal variations in extinction for non-ideal photometric sequences can be reduced to 0.025 mag per source, which is promising for its application in StarDICE.

At the end of their lives the most massive stars collapse into black holes (BHs). The detection of an 85 $M_{\odot}$ BH from GW 190521 appeared to challenge the upper-mass limit imposed by pair-instability (PI). Using systematic MESA calculations with new mass-loss implementations, we show that 100 $M_{\odot}$ stars at metallicities below 0.1 $Z_{\odot}$ can evolve into blue supergiant progenitors with cores small enough to avoid PI, yet with limited envelope loss, yielding remnants within the second mass gap. The key ingredients involve (i) a proper consideration of internal mixing and (ii) physically motivated stellar winds. Our modelling provides a robust pathway that roughly doubles the maximum BH mass permitted by PI theory and establish a physically-consistent framework to explore the upper BH mass limit versus metallicity. For rapid rotation ($\ge$50\% of critical), the upper BH mass comes down to $\simeq$35 $M_{\odot}$, matching the LIGO/Virgo BH mass pile-up.

The observational dearth of black holes (BHs) with masses between $\sim$100 and 100,000 $M_\odot$ raises questions about the nature of intermediate-mass black holes (IMBHs). Proposed formation channels for IMBHs include runaway stellar collisions and repeated binary BH (BBH) mergers driven by dynamical interactions in stellar clusters, but the formation efficiency of these processes and the associated IMBH occupation fraction are largely unconstrained. In this work, we study IMBH formation via both mechanisms in young, globular, and nuclear star clusters. We carry out a comprehensive investigation of IMBH formation efficiency by exploring the impact of different seeding models and star cluster formation histories. We employ a new version of the B-POP population synthesis code, able to model several seeding mechanisms as well as hierarchical BBH mergers. We quantify the efficiency of IMBH production across different cluster families, and estimate the fraction of BBH mergers involving an IMBH primary. Comparison with low-redshift IMBH candidates suggests that, depending on the seeding mechanism, stellar collisions can play a pivotal role in explaining potential IMBHs in local globular clusters. Our simulations highlight stellar collisions as the primary IMBH formation channel across a wide range of cluster types. They further suggest that wandering IMBHs may populate Milky Way-like galaxies and that correlations between cluster and IMBH masses can help distinguish the origins of Galactic globular clusters.

This study utilizes "Al-Wardat's method for analysing binary and multiple stellar systems" to estimate a set of parameters for the triple system Hip70868. The method compares the system's observational magnitudes, color indices, and spectral energy distribution (SED) and synthetic SEDs generated through atmospheric modeling of each component. Feedback-adjusted parameters and an iterative approach were employed to achieve the best fit between observational (including the latest measurements of Gaia, release DR3) and synthetic spectral energy distributions. The findings were completed using the distance of 71.89 pc given by Hipparcos 2007's new reduction. The individual components' parameters for the system were derived afterward. The parameters obtained for the individual components are as follows: Component A has an effective temperature (Teff) of 6000 +- 50 K, a surface gravity (log ga) of 4.50 +- 0.05, and a radius (Ra) of 1.43 +- 0.07 R_sun. Component B has a (Teff) of 5910 +- 50 K, a (log gb) of 4.40 +- 0.05, and a radius (Rb) of 1.35 +- 0.07 R_sun. The spectral types of the components were found to be F9 IV and G1 IV, respectively. The findings from this analysis were utilized to accurately position the two system components on the Hertzsprung-Russell (H-R) diagram and the evolutionary tracks. The analysis shows that the components have transitioned from the main sequence to the sub-giant stage of their evolution.

Accretion of metal-poor gas is expected to be an important channel of gas replenishment in galaxy evolution studies. However, observational evidence of this process is still relatively scarce. The unusual polar disk galaxy VGS 12 was found in the Void Galaxy Survey. It appears to be isolated and resides in the cosmological wall between two large voids. The suggested formation scenario for this peculiar system is accretion of metal-poor gas from the void interior. We present the data on the gas-phase chemical abundance of VGS 12 obtained with the Russian 6m telescope BTA. We complement our analysis with HI data obtained with VLA and the data on the kinematics of the ionized gas. VGS 12 appears to be a strong outlier from the "metallicity - luminosity" relation, with gas oxygen abundance ~0.7dex lower than expected for its luminosity. The nitrogen abundance, on the other hand, is higher than what is typically observed in galaxies with similar metallicity, but is consistent with the metallicity expected given its luminosity. Such behavior is what is expected in the case of metal-poor gas accretion. The HI reveals clear morphological and kinematical asymmetry between the northern and southern parts of the disk, which are likely related to its unsettled state due to the recent accretion event. The kinematics of the ionized gas seen in Halpha reveal prolate rotation and follow closely the rotation of the HI disk, so we suggest this is accreted HI gas ionized by the stars in the central region of the galaxy. Together, our findings provide strong, multiwavelength evidence of ongoing cold gas accretion in a galaxy caught in the act of growing from the cosmic web. This is one of the very few individual galaxies where a convincing case can be made for such a process, and demonstrates the potential for cold accretion to contribute to galaxy growth even in the low-redshift universe.

We report high spectral resolving power optical observations of comet C/2017\,K2 (PanSTARRS) as it approached the Sun. This comet was discovered when it was 16\,{\sc au} from the Sun. At discovery, the comet had a large and relatively bright coma. However, the spectrum at discovery showed only signatures of dust. We used the coud{é} spectrograph on the McDonald Observatory 2.7\,m telescope to obtain spectra, starting when the comet was at a heliocentric distance of 5.06\,{\sc au} and following it until 2.47\,{\sc au}, to determine what spectral features would appear at each heliocentric distance. The first heliocentric distance for which we detected any emission from the gas was 3.39\,{\sc au}, when we first detected CN. As the comet continued inward towards the Sun, various other species were detected. We discuss the implications of the early turn-on of CN and of species first appearing at different heliocentric distances in the context of control of the activity by water.

This paper presents an equilibrium model of a Milky Way-like spiral galaxy that supports open, mostly 2- and 3-arm spiral patterns but does not form a bar. It is suggested as a more realistic alternative model to that employed by the Agora collaboration; their model has a much lower disk mass and therefore forms only multi-arm spiral patterns. This improved model should enable simulations that test star-formation and feedback models in a more realistic isolated galaxy. Three versions of the same model having $2.1\times 10^5$, $2.1\times 10^6$, and $2.1\times 10^7$ particles are available for download.

The structure, extent, and mass of the Milky Way's (MW) dark matter (DM) halo are observationally challenging to determine due to our position within the Galaxy. To overcome this limitation, we study a combined sample of 127 MW analogs from the IllustrisTNG-50 cosmological simulation with observations of 11 nearby galaxies. Using both spatial and spectral high-resolution data from VLA and GMRT telescopes, we employ the 3D-Barolo algorithm to derive precise kinematic maps and rotation curves (RCs). To perform a careful analysis of the stellar component, we use Spitzer mid-IR imaging at 3.6 and 4.5um. We decompose the RCs into their different mass components, enabling the construction of a DM radial profile for each galaxy. By using a MCMC-based routine, we account for the DM contribution for the observed RCs. For our simulated sample, we obtain DM radial profiles directly from the TNG50 database. We probe for the universality of the DM profiles by deriving and comparing the equivalent local DM density (LDMD), a critical parameter linked to DM direct detection experiments on Earth. We calculate the DM density at the corresponding location of the Sun in each of the analogs. Our analysis yields a final LDMD range of 0.17-0.46 GeV cm^-3. Finally, by leveraging our mass estimates (M200}, Mgas and Mstar), we contextualize our findings with the efficiency of star formation in MW analogs and with the diversity of galaxies inhabiting similar halo masses.

We present results from very deep (485 ks) Chandra X-ray observations of the relaxed, cool core cluster Abell 2029 (z = 0.0767). A2029 hosts one of the longest, most continuous sloshing spirals ever observed, which we find extends nearly 600 kpc from the cluster core. In addition to providing detailed views of the sloshing spiral, imaging and spectroscopic analysis reveals ICM substructure related to the merger history including a broad ``splash'' of cooler gas and a potential merger shock. The radio lobes of the central WAT source show evidence of alignment with the sloshing motions, consistent with ICM bulk flow, rather than host-galaxy motion, being the primary driver of lobe bending. Comparison to a 1:10 mass-ratio off-axis merger simulation indicates that the observed ICM structures are relics of a second core passage of a subcluster ~4 Gyr after the start of the merger, where the ``splash'' feature is revealed to be a wake of cool gas trailing behind the subcluster. Overall, our results suggest that A2029 is still settling from past interactions -- showing that even the initially most relaxed-looking clusters can be hiding a rich history of dynamical activity.

The AXIS Community Science Book represents the collective effort of more than 500 scientists worldwide to define the transformative science enabled by the Advanced X-ray Imaging Satellite (AXIS), a next-generation X-ray mission selected by NASA's Astrophysics Probe Program for Phase A study. AXIS will advance the legacy of high-angular-resolution X-ray astronomy with ~1.5'' imaging over a wide 24' field of view and an order of magnitude greater collecting area than Chandra in the 0.3-12 keV band. Combining sharp imaging, high throughput, and rapid response capabilities, AXIS will open new windows on virtually every aspect of modern astrophysics, exploring the birth and growth of supermassive black holes, the feedback processes that shape galaxies, the life cycles of stars and exoplanet environments, and the nature of compact stellar remnants, supernova remnants, and explosive transients. This book compiles over 140 community-contributed science cases developed by five Science Working Groups focused on AGN and supermassive black holes, galaxy evolution and feedback, compact objects and supernova remnants, stellar physics and exoplanets, and time-domain and multi-messenger astrophysics. Together, these studies establish the scientific foundation for next-generation X-ray exploration in the 2030s and highlight strong synergies with facilities of the 2030s, such as JWST, Roman, Rubin/LSST, SKA, ALMA, ngVLA, and next-generation gravitational-wave and neutrino networks.

The subsolar point, the closest location on Earth's surface to the Sun, marks the Sun-Earth line of gravity that governs Earth's coupled orbital-rotational cycle. We examined the dynamic interactions among the Sun meridian declination (SMD), the Equation of Time (EoT), Earth's rotational speed (ER$_\omega$) -- equatorial and with respect to the Sun -- and the path of the subsolar point (NBI) across longitude, including time derivatives up to the fourth order (snap). A central finding was that the function NBI$_\alpha$(SMD) traces a lemniscate whose temporal structure mirrors the analemma, EoT(SMD), and whose symmetry converges to the obliquity component of the EoT. The EoT velocity ($\omega^*$) peaks at solstices, troughs near the equinoxes, and crosses zero every mid-season. ER$_\omega$ decreases monotonically along trans-equinoctial phases where the net drives of EoT and SMD coincide, and increases along trans-solstitial phases, where their net drives oppose. Eight sharp kinematic periods were identified for the cycle SMD-EoT-ER$_\omega$: two equinoctial, two solstitial, and one within each season. The non-solstitial sharp terms, defined by ZCPs and troughs of $\omega^*$, display a consistent 3$^\circ$ northward offset from the function NBI$_\alpha$(SMD). These results reveal a direct dynamical link between SMD, EoT, and Earth's rotational speed, providing a novel framework for understanding Earth's rotation.

Recent neutrino observations from the IceCube Collaboration suggest that Seyfert galaxies are promising candidate sources of neutrinos. Within the standard disk-corona model, we assume that protons are accelerated by a non-resonant acceleration mechanism driven by magnetized turbulence in the corona. These accelerated protons interact with ambient radiation or matter, producing high-energy neutrinos and gamma rays. In this scenario, gamma rays are largely absorbed within the corona. The neutrino luminosity depends primarily on the properties of the corona (such as the X-ray luminosity and radius) and the spectral energy distribution of the target photons. This study demonstrates the relation between the neutrino luminosity and the X-ray luminosity, and further discusses the contribution of cascade gamma rays to coronal radiation. Notably, MeV gamma rays can effectively escape the source, together with neutrinos, and serve as key observational probes for testing this model. Future MeV gamma-ray telescopes, such as AMEGO-X and e-ASTROGAM, are expected to detect such gamma-ray signatures, providing a critical multi-messenger test of the hadronic corona model.

We present a comparative study of carbon-rich asymptotic giant branch (CAGB) stars in the Large Magellanic Cloud (LMC; 7347 stars) and the Milky Way (7163 stars) using infrared color-magnitude diagrams (CMDs), spectral energy distributions (SEDs), two-color diagrams (2CDs), and variability data. Observed SEDs are compared with theoretical models to characterize the central stars and their circumstellar dust envelopes and to estimate distances. For the LMC, a set of best-fitting CAGB models is derived by fitting observed SEDs with radiative transfer models, utilizing the galaxy's well-established distance. For Galactic CAGB stars, where Gaia DR3 parallaxes are uncertain, we estimate distances by fitting observed SEDs with the CAGB models validated against LMC stars, and for Mira variables, from the period-magnitude relation calibrated with LMC Miras. A comparison of these approaches demonstrates that SED-based distances are both reliable and practical for a large sample of Galactic CAGB stars. We find that CAGB stars in both galaxies show broadly similar infrared properties, although the LMC sample lacks stars with extremely thick dust envelopes.

Planet formation may begin much earlier than previously expected, when the protoplanetary disk is still massive and gravitationally unstable. It has been proposed that solid grains can concentrate in the spiral arms of self-gravitating disks, leading to the formation of planetary embryos or cores that can greatly accelerate the process of planet formation. We perform hydrodynamic simulations of self-gravitating gas and even smaller dust grains than previously investigated in 3-dimensional shearing box simulations to explore the conditions necessary to form these planetary seeds. Focusing on small grains of dimensionless stopping time $\mathrm{St}=0.01$ and shorter, we find that disk metallicities $Z \gtrsim 0.02$ can overcome the disruptive effects of dust diffusion among these small dust grains. In the outer reaches of a gravitationally unstable disk, these models correspond to grains of approximately 1$\,mm$ and lead to planetary embryos between 0.1 and 1 Earth mass. The formation of these planetary embryos could therefore reduce the time needed for planet assembly, particularly in the outer regions of the disk where coagulation timescales are longer and solid growth is limited.

Understanding dispersal of protoplanetary disks remains a central challenge in planet formation theory. Disk winds, driven by magnetohydrodynamics (MHD) and/or photoevaporation, are now recognized as primary agents of dispersal. With the advent of James Webb Space Telescope (JWST), spatially resolved imaging of these winds, particularly in H2 pure rotational lines, has become possible, revealing X-shaped morphologies and integrated fluxes of $\sim 10^{-16}$-$10^{-15}{\rm \,erg\,s^{-1}\,cm^{-2}}$. However, the lack of theoretical models suitable for direct comparison has limited interpretation of these features. To address this, we present the first model of photoevaporative \ce{H2} winds tailored for direct comparison with JWST observations. Using radiation hydrodynamics simulations coupled with chemistry, we derive steady-state wind structures and post-process them to compute H2 level populations and line radiative transfer, including collisional excitation and spontaneous decay. Our synthetic images reproduce the observed X-shaped morphology with radial extents of $\gtrsim 50$-$300{\rm \,au}$ and semi-opening angles of $\sim 37^\circ$-$50^\circ$, matching observations of Tau 042021 and SY Cha. While the predicted line fluxes are somewhat lower than the observed values. These results suggest that photoevaporation is a viable mechanism for reproducing key features of observed H2 winds, including morphology and fluxes, though conclusive identification of the wind origin requires source-specific modeling. This challenges the reliance on geometrical structures alone to distinguish between MHD winds and photoevaporation. Based on our findings, we also discuss alternative diagnostics of photoevaporative winds. This work provides a critical first step toward interpreting spatially resolved H2 winds and motivates future modeling efforts.

The search for life in the Solar System hinges on data from planetary missions. Biosignatures based on molecular identity, isotopic composition, or chiral excess require measurements that current and planned missions cannot provide. We introduce a new class of biosignatures, defined by the statistical organization of molecular assemblages and quantified using ecodiversity metrics. Using this framework, we analyze amino acid diversity across a dataset spanning terrestrial and extraterrestrial contexts. We find that biotic samples are consistently more diverse, and therefore distinct, from their sparser abiotic counterparts. This distinction holds for fatty acids as well, indicating that the diversity signal reflects a fundamental biosynthetic signature. It also proves persistent under space-like degradation. Relying only on relative abundances, this biogenicity assessment strategy is applicable to any molecular composition data from archived, current, and planned planetary missions. By capturing a fundamental statistical property of life's chemical organization, it may also transcend biosignatures that are contingent on Earth's evolutionary history.

The China Space Station Telescope (CSST) will conduct a deep and wide imaging survey in the NUV-, u-, g-, r-, i-, z-, and y-bands. In this work, using theoretical data synthesized from the BOSZ spectra of Bohlin et al. (2017), along with observational data constructed from different sources, we present two methods for estimating stellar parameters from CSST-like photometry. One approach is to estimate metallicity [M/H] and surface gravity log g simultaneously by using the metallicity- and log g-dependent stellar loci. Tests with theoretical data (without photometric errors) result in precisions of 0.088 dex and 0.083 dex for [M/H] and log g, respectively. With 0.01 mag photometric errors, precision is degraded by about a factor of two, due to degeneracy in [M/H] and log g. Tests with observational data, although with larger photometric errors, result in precisions of 0.10 dex and 0.39 dex for [Fe/H] and log g, respectively, thanks to the strong correlation between stellar colors and log g in real data. The other approach is the giant-dwarf loci method to obtain classifications and metallicity estimates. With the same observational data, it achieves a better [Fe/H] precision of 0.084 dex, due to the stronger constraints imposed on log g. The method also performs well in distinguishing giants from dwarfs, particularly for red or metal-poor giants. This work demonstrates the clear potential of the CSST data, paving the way for stellar-parameter estimates for many billions of stars.

The Legacy Survey of Space and Time (LSST) at the Vera C. Rubin Observatory will capture light curves (LCs) for 10 billion sources and produce millions of transient candidates per night, necessitating scalable, accurate, and efficient classification. To prepare the community for this scale of data, the Extended LSST Astronomical Time-Series Classification Challenge (ELAsTiCC) sought to simulate a diversity of LSST-like time-domain events. Using a small transformer-based model and refined light curve encoding logic, we present a new state of the art classification performance on ELAsTiCC, with 71.8% F1 on LC-only classifications, and 89.8% F1 on LC+metadata classifications. Previous state of the art was 65.5% F1 for LC-only, and for LC+metadata, 84% F1 with a different setup and 83.5% F1 with a directly comparable setup. Our model outperforms previous state-of-the-art models for fine-grained early detection at all time cutoffs, which should help prioritize candidate transients for follow-up observations. We demonstrate label-efficient training by removing labels from 90% of the training data (chosen uniformly at random), and compensate by leveraging regularization, bootstrap ensembling, and unsupervised pretraining. Even with only 10% of the labeled data, we achieve 67.4% F1 on LC-only and 87.1% F1 on LC+metadata, validating an approach that should help mitigate synthetic and observational data drift, and improve classification on tasks with less labeled data. We find that our base model is poorly calibrated via reliability diagrams, and correct it at a minimal cost to overall performance, enabling selections by classification precision. Finally, our GPU-optimized implementation is 9x faster than other state-of-the-art ELAsTiCC models, and can run inference at ~33000 LCs/s on a consumer-grade GPU, making it suitable for large-scale applications, and less expensive to train.

Dust dynamics plays a critical role in astrophysical processes and has been modeled in hydrodynamical simulations using various approaches. Among particle-based methods like Smoothed Particle Hydrodynamics (SPH), the One-Fluid model has proven to be highly effective for simulating gas-dust mixtures. This study presents the implementation of the One-Fluid model in OpenGadget3, introducing improvements to the original formulation. These enhancements include time-dependent artificial viscosity and conductivity, as well as a novel treatment of dust diffusion using a pressure-like term. The improved model is tested using a suite of dust dynamics benchmark problems: DUSTYBOX, DUSTYWAVE, and DUSTYSHOCK, with the latter extended to multidimensional scenarios, as well as a dusty Sedov-Taylor blast wave. Additional tests include simulations of Cold Keplerian Disks, dusty protoplanetary disks, and Kelvin-Helmholtz instabilities to evaluate the model's robustness in more complex flows. The implementation successfully passes all standard benchmark tests. It demonstrates stability and accuracy in both simple and complex simulations. The new diffusion term improves the handling of flows with large dust-to-gas ratios and low drag coefficients, although limitations of the One-Fluid model in these regimes remain. The enhanced One-Fluid model is a reliable and robust tool for simulating dust dynamics in OpenGadget3. While it retains some limitations inherent to the original formulation, the introduced improvements expand its applicability and address some challenges in gas-dust dynamics.

The circumnuclear region of the Galactic Center offers a unique laboratory to study energy balance and structure formation around Sgr A$\star$. This work investigates thermal and nonthermal processes within 7 pc distance from Sgr A$\star$. Using MeerKAT 1.3 GHz radio continuum data and ALMA H40 radio recombination line emission from the ACES survey, we separate free-free and synchrotron components at $\sim$0.2 pc resolution. With a thermal fraction of $\simeq$13%, the 1.3 GHz emission shows tight correlations with the Herschel PACS infrared data. The correlation between the equipartition magnetic field and molecular gas traced by JCMT $^{12}$CO (J=3$\rightarrow$2) observations reveals a balance between the magnetic field, cosmic rays, and molecular gas pressures south of the circumnuclear disk on $\sim$0.7 pc scales. Unlike the magnetic field and ionized gas, the molecular gas density declines in the cavity (R$\leq$2 pc) toward the center, likely due to feedback from Sgr A$\star$. We find that nonthermal pressure from turbulent gas nearly balances magnetic and cosmic ray pressures and exceeds thermal pressure by two orders of magnitude. The medium surrounding Sgr A$\star$ is filled by a low-$\beta$ (thermal-to-magnetic energy), supersonic plasma, with an Alfvén Mach number $\simeq$ 4 (assuming equipartition). Analysis of the mass-to-magnetic flux ratio suggests that the circumnuclear region is mostly subcritical and, therefore, the magnetic field can help stabilize gas clouds against gravitational collapse.

Optical and infrared surveys have detected increasing numbers of disc accretion outbursts in young stars. Some models of these FU Ori-type events predict that the outburst should start at near- to mid-infrared wavelengths before an optical rise is detected, and this lag between infrared and optical bursts has been observed in at least two systems. Detecting and characterizing infrared precursors can constrain the outburst trigger region, and thus help identify the mechanism producing the outburst. However, because FU Ori objects are generally young and usually embedded in dusty protostellar envelopes, it is not clear whether or how well such infrared precursors can be detected in the presence of strong envelope extinction. To explore this question, we combine time-dependent outburst models of the inner disc with an outer dusty disc and protostellar envelope, and calculate the resulting spectral energy distributions (SEDs) using the radiative transfer code RADMC3D. We find that, for envelope mass infall rates about 10^{-5} Msun/yr (rc/30 au)^{-1/2}, where rc is a characteristic inner radius for the infalling envelope, the infrared precursor is only apparent in the SED when viewed along the outflow cavity. At other inclinations, the precursor is most easily distinguished at infall rates of 10^{-6} Msun/yr (rc/30 au)^{-1/2}. We also show that far-IR and submm/mm monitoring can enable the indirect detection of precursor evolution long before the optical outburst, emphasizing the potential of long-wavelength monitoring for studying the earliest stages of protostar formation.

We present an analysis of the gas-phase mass-metallicity relationship (MZR) and fundamental metallicity relationship (FMR) for $65$ star-forming galaxies at $2 < z < 8$ from the JWST/EXCELS survey. We calculate gas-phase metallicities (12 + log(O/H)) using strong-line calibrations explicitly tested against the EXCELS sample, and report direct-method metallicities for $25$ galaxies. Our sample spans $8.1<\log(\rm M_\star/M_\odot)<10.3$ in stellar mass and $0<\log(\rm SFR/M_\odot \, yr^{-1})<2$ in star-formation rate, consistent with typical main-sequence star-forming galaxies at the same redshifts. We find a clear MZR at both $2<z<4$ ($\langle z \rangle = 3.2$) and $4<z<8$ ($\langle z \rangle = 5.5$), with consistent slopes and mild evolution in normalization of $\simeq 0.1 \, \mathrm{dex}$, matching trends from simulations and recent observations. Our results demonstrate rapid gas-phase enrichment in the early Universe, with galaxies at fixed mass reaching $\simeq 50$ per cent of their present-day metallicity by $z \simeq 3$ (within the first $\simeq 15$ per cent of cosmic time). We find tentative evidence for SFR-dependence in the MZR scatter, though the results remain inconclusive and highlight the need for larger high-redshift samples. Comparison with locally derived FMRs reveals a clear offset consistent with other $z > 3$ studies. We discuss potential drivers of this offset, noting that high-redshift samples have significantly different physical properties compared to local samples used to define the $z=0$ FMR. Our results confirm that low-mass, high specific star-formation rate galaxies common at high redshift are inconsistent with the equilibrium conditions underlying the local FMR, and highlight the rapid chemical enrichment at early cosmic epochs.

The ratio of radially to tangentially polarized Thomson-scattered white light provides a powerful tool for locating the 3D position of compact structures in the solar corona and inner heliosphere, and the Polarimeter to Unify the Corona and Heliosphere (PUNCH) has been designed to take full advantage of this diagnostic capability. Interestingly, this same observable that establishes the position of transient blob-like structures becomes a local measure of the slope of the global falloff of density in the background solar wind. It is thus important to characterize the extent along the line of sight of structures being studied, in order to determine whether they are sufficiently compact for 3D positioning. In this paper, we build from analyses of individual lines of sight to three-dimensional models of coronal mass ejections (CMEs), allowing us to consider how accurately polarization properties of the transient and quiescent solar wind are diagnosed. In this way, we demonstrate the challenges and opportunities presented by PUNCH polarization data for various quantitative diagnostics.

Observations of HI published in 1957 by Westerhout and Schmidt were presented as showing a global face-on view of spiral structure in the Milky Way. Since then many studies have attempted to improve on the early map, perhaps presupposing our Galaxy to be characterized by a Grand-design pattern of prominent spiral arms. We consider here two approaches to explore the nature of spiral structure of the inner Milky Way disk using the HI4PI survey. The first is to search for shallow shoulders in the high-velocity wings of HI data along the Galactic equatorial disk of the inner Milky Way that would be expected if the lines of sight swept across interarm regions of low HI density. The second is to look for broad dips in the integrated HI brightness temperature over the high-velocity wings, pertaining to gas near the subcentral region, that would be expected for the interarm region of a Grand-design. We find neither shallow shoulders nor broad dips in either the Northern quadrant I or the Southern quadrant IV indicating that the Milky Way seen interior to the Solar orbit is not characterized by a majestic spiral-structure Grand-design; this conclusion is a robust one, in that it does not depend on measures of distance. Taken together with decades of work on the bits and pieces of the quite disorganized shambles of the inner Galaxy, we suggest that the Milky Way belongs to the category of Flocculent spirals.

By using various data sources for the stellar fluxes in overlapping campaign fields and employing full time series modeling, we report the detection of the secondary eclipses of two brown dwarfs (CWW 89Ab = EPIC 219388192b and HSHJ 430b = EPIC 211946007b). The detections yielded timings in agreement with the orbital elements derived from the earlier radial velocity measurements and eclipse depths of 70+/-12 ppm (CWW 89Ab) and 852+/-123 ppm (HSHJ 430b). While the high depth in the Kepler waveband for HSHJ 430b is in agreement with the assumption that the emitted flux comes mostly from the internal heat source and the absorbed stellar irradiation, the case of CWW 89Ab suggests very high albedo, because of the lack of sufficient thermal radiation in the Kepler waveband. Assuming completely reflective dayside hemisphere, without circulation, the maximum value of the eclipse depth due to the reflection of the stellar light is 56 ppm. By making the extreme assumption that the true eclipse depth is 3 sigma less than the observed depth, the minimum geometric albedo becomes ~0.6.

We investigate the formation of plasma cavities in unmagnetized relativistic pair shocks and demonstrate that these cavities emerge naturally as a nonlinear consequence of asymmetric Weibel instability. We provide an intuitive physical picture and a minimal fluid model that captures the essential features of this cavitation instability and compare them with PIC results. This mechanism may provide the missing link between kinetic Weibel turbulence and macroscopic magnetic fields in astrophysical shocks.

Strong gravitational lensing time-delay measurements, together with the distance sum rule (DSR), offer a model-independent approach to probe the geometry and expansion of the universe without relying on a fiducial cosmological model. In this work, we perform a cosmographic analysis by combining the latest Type Ia supernova datasets (PantheonPlus, DESY5, and Union3), baryon acoustic oscillation data from DESI-DR2, and updated time-delay distances from strong lensing systems. The analyses using SGL with individual SNIa datasets (SGL+PantheonPlus, SGL+DESY5, and SGL+Union3) indicate a preference for an open universe, though they remain consistent with spatially flat universe at the $95%$ confidence level. When DESI-DR2 data is included in each combination, the constraints tighten and shift slightly toward a closed universe, while flatness remains supported at the $68%$ confidence level. The best-fit values of $q_0$ and $j_0$ agree with $\Lambda$CDM expectations within $95%$ or $99%$ confidence depending on the dataset, whereas $s_0$ remains weakly constrained in all cases. This work is the first in a series of two companion papers on cosmography with DESI-DR2 and strong lensing.

The distance ratio derived from strong gravitational lensing systems, combined with complementary cosmological observations, offers a model-independent means to investigate the geometry and dynamics of the universe. In this study, we carry out a cosmographic investigation using the latest compilations of Type Ia supernovae (PantheonPlus, DESY5, and Union3), baryon acoustic oscillation measurements from DESI-DR2, and updated strong lensing distance ratios. The cosmographic series is expanded to fourth order in the variable $y = z/(1+z)$ to constrain the deceleration, jerk, and snap parameters $(q_0,~j_0,~s_0)$. The analysis utilizes the distance sum rule (DSR) to provide an independent assessment of the spatial curvature parameter, $\Omega_{k0}$, without assuming a specific dynamical model. Our results based on SGL distance ratio measurements combined with individual supernova datasets suggest a mild preference for an open universe, though a flat universe is supported at the 95% confidence level. Further, the inclusion of DESI-DR2 data in each combination provides tighter constraints on the parameters and confirms flatness within the 68% confidence level as expected in standard cosmology. The results for $q_0$ and $j_0$ are consistent with $\Lambda$CDM predictions across datasets, while the constraint on $s_0$ remains limited but improves with the inclusion of DESI-DR2. This is the second and final paper in a two-part series.

Techniques using multiple tracers of the large scale structure of the universe show great promise for examining the fundamentals of our Universe's cosmology. Such techniques rely on the different relationship between the overdensity of tracers and the broader matter overdensity, enabling cosmic-variance-free tests of primordial non-Gaussianity in the initial curvature perturbations. There is a great opportunity for current and future all-sky extra-galactic radio surveys to make use of this technique to test for non-Gaussianity at a precision greater than existing all-sky constraints from the cosmic microwave background. To realize this goal there is a need for accurate simulations. Previous radio galaxy simulations have either been realistic but covering only a small area (and so unhelpful for cosmological forecasts), or all-sky dark matter only cosmological simulations but having no connection to a real radio galaxy population. In this study, we use the FLAMINGO suite of cosmological surveys, as well as the matching of dark matter halos to radio galaxy population, to create an accurate sky simulation in order to examine the feasibility of multi-tracer techniques. We present an analysis of the clustering (with a bias model for the simulation), as well as redshift distributions, source counts and radio luminosity functions, and discuss future work on non-Gaussianity detection.

Neutrinos with Standard Model interactions free-stream in the early Universe, leaving a distinct phase shift in the pattern of baryon acoustic oscillations (BAO). When isolated, this phase shift allows one to robustly infer the presence of the cosmic neutrino background in BAO and cosmic microwave background (CMB) data independently of other cosmological parameters. While in the context of the Standard Model, this phase shift follows a known scale-dependent relation, new physics in the cosmic neutrino background could alter the overall shape of this feature. In this paper, we discuss how changes in the neutrino phase shift could be used to constrain self-interactions among neutrinos. We produce simple models for this phase-shift assuming universal self-interactions, and use these in order to understand what constraining power is available for the strength of such interactions in BAO and CMB data. We find that, although challenging, it may be possible to use a detection of the phase to put a more robust limit on the strength of the self-interaction, $G_{\mathrm{eff}}$, which at present suffers from bimodality in cosmological constraints. Our forecast analysis reveals that BAO data alone will not provide the precision needed to tightly constrain self-interactions; however, the combined analysis of the phase shift signature in both CMB and BAO can potentially provide a way to detect the impact of new neutrino interactions. Our results could be extended upon for models with non-universal interactions.

The cosmological principle, which asserts a statistically homogeneous and isotropic universe on large scales, is a foundational assumption of the standard cosmological model. A critical test of this principle involves the kinematic interpretation of the Cosmic Microwave Background temperature dipole, conventionally attributed to our peculiar motion relative to the cosmic rest frame. The Ellis-Baldwin test provides a probe of this kinematic interpretation by searching for a matching Doppler-driven dipole in the number counts of extragalactic radio sources. Recent measurements from the CatWISE2020 quasar catalog have reported a dipole amplitude significantly exceeding the kinematic expectation, with a claimed significance of $4.9\sigma$. We present a comprehensive reassessment of this test using the same dataset, incorporating major sources of uncertainty in the statistical inference. We use a simulation framework based on the FLASK package, incorporating lognormal realizations of the large-scale structure, the quasar clustering bias, the survey's radial selection function, and its exact sky coverage. Our simulations account for the kinematic dipole, the intrinsic clustering dipole, shot noise, and survey geometry effects. The analysis yields a revised significance of the kinematic dipole excess of $3.63\sigma$ in the absence of a clustering dipole, and $3.44\sigma$ in the presence of a randomly oriented clustering dipole. When the clustering dipole is aligned with the kinematic dipole direction, the significance decreases further to $3.27\sigma$. Our analysis demonstrates that although the anomaly is reduced in significance, it cannot be explained solely as a result of the clustering dipole or mode coupling arising from the survey mask.

The Missing Mantle Problem refers to the apparent scarcity of olivine rich (A-type) asteroids in the main belt, despite expectations that such bodies should be common if differentiated parent bodies were widely disrupted. Conversely, A-types appear relatively more abundant among near-Earth asteroids. We present a revised estimate of the A-type abundance in the main belt by combining Gaia Data Release 3 (DR3) reflectance spectra with near-infrared observations from NASA IRTF. We applied principal component analysis (PCA) to Gaia DR3 visible spectra to identify A-type candidates and confirmed a subset through IRTF spectroscopy. Using these data and literature results, we derived the A-type probability distribution as a function of DR3 principal components, and from this, estimated their abundance across heliocentric distances and collisional families. We find that A-types constitute (2.00 +/- 0.15)% of main-belt asteroids significantly higher than previous estimates. Some families, such as Vesta and Flora, show enhanced A-type fractions, while others (e.g. Themis, Hygiea) contain few or none. The elevated abundance in the Flora family supports the existence of an additional differentiated parent body in the inner belt, besides Vesta. These findings indicate that olivine-rich material is more widespread than previously thought, offering new constraints on the Missing Mantle Problem and on early Solar System differentiation processes.

Taking advantage of the near-infrared calcium triplet lines, we determine metallicities for a sample of more than 3,500 red giant stars in the field of the Small Magellanic Cloud (SMC). We find a median metallicity of [Fe/H]=-1.05$\pm$0.01 dex with a negative metallicity gradient of -0.064$\pm$0.007 dex deg$^{-1}$ between 1.2°~to 6.0°consistent with an outside-in evolution scenario. For the first time, we detect hints of a positive metallicity gradient within 1.2°, likely reflecting radial migration or centralised chemical enrichment. Azimuthal metallicity asymmetries are detected, with flatter gradients in the eastern and southern quadrants and steeper ones in the north and west. They are consistent with tidal interaction effects from the Large Magellanic Cloud (LMC). Finally, in spite of a clear distance and velocity bifurcations in the east, they seem to share a common chemical origin, in agreement with other studies.

Models describing dark matter as a novel particle often predict that its annihilation or decay into Standard Model particles could produce a detectable neutrino flux in regions of high dark matter density, such as the Galactic Center. In this work, we search for these neutrinos using $\sim$9 years of IceCube-DeepCore data with an event selection optimized for energies between 15 GeV to 200 GeV. We considered several annihilation and decay channels and dark matter masses ranging from 15 GeV up to 8 TeV. No significant deviation from the background expectation from atmospheric neutrinos and muons was found. The most significant result was found for a dark matter mass of 201.6 GeV annihilating into a pair of $b\bar{b}$ quarks assuming the Navarro-Frenk-White halo profile with a post-trial significance of $1.08 \;\sigma$. We present upper limits on the thermally-averaged annihilation cross-section of the order of $10^{-24} \mathrm{cm}^3 \mathrm{s}^{-1}$, as well as lower limits on the dark matter decay lifetime up to $10^{26} \mathrm{s}$ for dark matter masses between 5 GeV up to 8 TeV. These results strengthen the current IceCube limits on dark matter masses above 20 GeV and provide an order of magnitude improvement at lower masses. In addition, they represent the strongest constraints from any neutrino telescope on GeV-scale dark matter and are among the world-leading limits for several dark matter scenarios.

In the aftermath of the Moon-forming giant impact, the Hadean Earth's mantle and surface crystallized from a global magma ocean blanketed by a dense volatile-rich atmosphere. While prior studies have explored the thermal evolution of such early Earth scenarios under idealized, oxidizing conditions, the potential feedback between tidal heating driven by Earth--Moon orbital forcing and variable redox scenarios have not yet been explored in detail. We investigate whether tidal heating could have prolonged this early magma ocean phase and supported quasi-steady state epochs of global radiative equilibrium: periods of thermal balance between outgoing radiation and interior heat flux. Using the $\texttt{PROTEUS}$ simulation framework, we simulate Earth's early evolution under a range of plausible tidal power densities, oxygen fugacities, and volatile inventories. Our results suggest that feedback between tidal heating and atmospheric forcing can induce substantial variation in magma ocean lifetimes, from $\sim$30 Myr up to $\sim$500 Myr, sensitive to interior redox conditions. Global radiative equilibrium epochs commonly arise across this range, lasting from $\sim$2 to $\sim$320 Myr, and typically occur from 24 Myr after the Moon-forming impact. Under oxidizing conditions, late-stage H$_2$O degassing promotes melt retention and sustained heating due to its significant contribution to greenhouse forcing. Weak tides increase the atmospheric abundance of H$_2$S and NH$_3$ and deplete CO. Therefore, the feedback between tides and atmospheric forcing induces a disequilibrium signature in the magma ocean atmosphere.

We present a modified Lu \& Hamilton-type model where the neighborhood relations are replaced by topological connections, which can be dynamically altered. The model represents each grid node as a flux tube, as in the classic model, but with connections evolving to capture the complex effects of magnetic reconnection. Through this framework, we analyze how the dissipated energy distribution changes, particularly focusing on the power-law exponent $\alpha_E$, which decreases with respect to the original model due to rewiring effects. When the system is dominated by rewiring, it presents an exponential distribution exponent $\beta_E$, showing a faster decay of dissipated energy than in the original model. This leads to microflare-dominated dynamics at short timescales, causing the system to lose the scale-free behavior observed in both the original model (Lu \& Hamilton 1991) and in configurations where energy release is primarily driven by forcing rather than rewiring. Our results reveal a clear transition from power-law to exponential regimes as the rewiring probability increases, fundamentally altering the energy distribution characteristics of the system. In contrast, when considering topological neighbors instead of local ones, the model's dynamics become intrinsically nonlocal. This leads to scaling exponents comparable to those reported in other nonlocal dynamical systems.

We probe the stellar mass growth in a sample of 568 Sunyaev-Zel'dovich (SZ) selected galaxy clusters with masses greater than $2.9 \times 10^{14} \mathrm{M_{\odot}}$ and redshifts in the range $0.2 < z < 0.8$, drawn from the fifth data release of the Atacama Cosmology Telescope (ACT DR5). By utilising deep photometry from the tenth data release of the Dark Energy Camera Legacy Survey (DECaLS DR10), we construct redshift- and cluster mass-binned composite cluster stellar mass functions (SMFs), down to $M_* = 10^{9.5} \mathrm{M_{\odot}}$. This work presents the first analysis of the cluster SMF for this specific cluster sample at this epoch. We find that the characteristic stellar mass ($M^*$) of the cluster SMF evolves marginally from $0.55 \leq z < 0.8$, with most of the measurable growth occurring at $ 0.2 < z < 0.55$. This suggests that most of the massive galaxy population in clusters ($M_* \gtrsim 10^{10.75} \mathrm{M_{\odot}}$) is largely established by $z \sim 0.8$, with subsequent evolution driven primarily by late-time assembly processes. The low-mass slope ($\alpha$) of the composite cluster SMF is flat at high-$z$ ($z \sim 0.8$) but steepens at $z < 0.55$, suggesting an abundance of massive galaxies in high-$z$ clusters compared to low-$z$ clusters. Redshift evolution of cluster stellar mass fractions ($f^{\mathrm{cg}}_{*}$) suggest that cluster stellar mass (from galaxies with $M_* > 10^{9.5} \mathrm{M_{\odot}}$) has grown by a factor of $3.3$ since $z = 0.8$.

Astrochemical models are essential to bridge the gap between the timescales of reactions, experiments, and observations. Ice chemistry in these models experiences a large computational complexity as a result of the many parameters required for the modeling of chemistry occurring on these ices, such as binding energies and reaction energy barriers. Many of these parameters are poorly constrained, and accurately determining all would be too costly. We aim to find out which parameters describing ice chemistry have a large effect on the calculated abundances of ices for different prestellar objects. Using Monte Carlo sampled binding energies, diffusion barriers, desorption and diffusion prefactors, and reaction energy barriers, we determined the sensitivity of the abundances of the main ice species calculated with UCLCHEM, an astrochemical modeling code, on each of these parameters. We do this for a large grid of physical conditions across temperature, density, cosmic ray ionization rate and UV field strength. We find that, regardless of the physical conditions, the main sensitivities of abundances of the main ice species are the diffusion barriers of small and relatively mobile reactive species such as H, N, O, HCO, and CH$_3$. Thus, these parameters should be determined more accurately to increase the accuracy of models, paving the way to a better understanding of observations of ices. In many cases, accurate reaction energy barriers are not essential due to the treatment of competition between reactions and diffusion.

We demonstrate that the suppression in the lensing power spectrum of the cosmic microwave background (CMB) caused by massive neutrinos can be mimicked by dark matter-baryon interactions at the precision of next-generation CMB experiments. Thus, a determination of neutrino masses from the CMB lensing power spectrum may be compromised. We illustrate the degeneracy for a dark matter-proton cross section $\propto v^{-4}$, which arises in the $t$-channel exchange of an ultralight mediator in the nonrelativistic limit.

The Seyfert Type II galaxy NGC 1068 has been identified as a potential neutrino source by IceCube, with a 4.2$\sigma $ significance detection of a 79$^{+22}_{-20}$ neutrino excess from 2011 to 2020, despite the absence of a gamma-ray counterpart. The observed high-energy neutrino emission indicates the presence of a hadronic component, along with strong gamma-ray absorption, likely via pair production, and efficient particle acceleration. In this work, we investigate turbulence-driven magnetic reconnection as a mechanism for particle acceleration in the coronal accretion flow surrounding the central black hole. We develop a one-zone model for both acceleration and emission, following the framework of de Gouveia Dal Pino and Lazarian (2005) and Kadowaki et al. (2015) to explore how fast magnetic reconnection in the inner coronal disk region accelerates protons and electrons, shaping the spectral energy distribution (SED). Our model incorporates strong pair production attenuation and interactions with optical, ultraviolet (OUV), and X-ray photon fields in the corona, which serve as effective targets for proton interactions. Unlike recent studies, we find that particle acceleration to the extreme energies required to explain observations is primarily driven by first-order Fermi acceleration within the turbulent reconnection layers in a large scale current sheet, rather than by drift acceleration. Additionally, we demonstrate that accelerated protons primarily lose energy through photopion interactions with the OUV background, subject to important constraints from the coronal X-ray emission.

Pulsar-like objects are extremely compact, with an average density that exceeds nuclear saturation density, where the fundamental strong interaction plays an essential role, particularly in the low-energy regime. The internal structures and properties of those objects are profoundly connected to phenomena such as supernova explosions, gamma-ray bursts, fast radio bursts, high/low-mass compact stars, and even to issues like dark matter and cosmic rays. However, due to the non-perturbative nature of quantum chromodynamics, significant uncertainties remain in our current understanding of the composition and equation of state (EOS) for the dense matter inside them. Drawing on three-flavour symmetry and the strong coupling between light quarks, this paper presents a novel perspective on the nature of pulsars: they are actually composed of strange matter, in the form of either strange quark matter or strangeon (analogous to nucleons and representing multibaryon states with three-flavour symmetry) matter. As both strange quark matter and strangeon matter contain non-zero strangeness, we refer to them collectively as ``strange matter'', and to the corresponding compact stars as ``strange stars''. We then briefly introduce several physical models describing strange matter and present the resulting structures and properties of strange stars. This includes discussions on the EOSs, surface properties, mass-radius relations, glitches, binary compact star mergers, and dark matter. Furthermore, we will explore how observational properties of pulsar-like objects support the strange star model.

We study the formation and evolution of stellar halos (SHs) around bright central galaxies (BCGs), focusing on their scaling relations, colors, and metallicities across cosmic time, and compare model predictions with ultra--deep imaging data. We use the semianalytic model \textsc{FEGA25}, applied to merger trees from high--resolution dark matter simulations, including an updated treatment of intracluster light (ICL) formation. SHs are defined as the stellar component within the transition radius, linked to halo concentration. Predictions are compared with observations from the VST Early-type GAlaxy Survey (VEGAS) and Fornax Deep Survey (FDS). The SH mass correlates strongly with both BCG and ICL masses, with tighter scatter in the SH--ICL relation. The transition radius peaks at 30--40 kpc nearly independent of redshift, but can reach $\sim400$ kpc in the most massive halos, after z=0.5. SHs and ICL show nearly identical color distributions at all epochs, both reddening toward $z=0$. At $z=2$, SHs and the ICL are $\sim0.4$ dex more metal--poor than BCGs, but the gap shrinks to $\sim0.1$ dex by the present time. Observed colors are consistent with model predictions, while observed metallicities are lower, suggesting a larger contribution from disrupted dwarfs. SHs emerge as transition regions between BCGs and the ICL, dynamically and chemically coupled to both. Their properties depend on halo concentration, ICL formation efficiency, and the progenitor mass spectrum. Upcoming wide--field photometric and spectroscopic surveys (e.g. LSST, WEAVE, 4MOST) will provide crucial tests by mapping structure, metallicity, and kinematics in large galaxy samples.

We report near-infrared spectral model fits to seven distant L- and T-type dwarfs observed with the JWST Near Infrared Spectrograph (NIRSpec) as part of the Red Unknowns: Bright Infrared Extragalactic Survey (RUBIES). Comparison of 0.9-2.5 $\mu$m near-infrared spectra of these sources to spectral standards indicates spectral types spanning L1 to T8, and spectrophotometric distances spanning 800-3,000 pc. Fits to three grids of spectral models yield atmosphere parameters and spectrophotometric distances largely consistent with our classifications, although fits to L dwarf spectra indicate missing components to the models. Three of our sources have vertical displacements from the Galactic plane exceeding 1 kpc, and have high probabilities of membership in the Galactic thick disk population. Of these, the L dwarf RUBIES-BD-3 (RUBIES-EGS-3081) is well-matched to subdwarf standards, while the early T dwarf RUBIES-BD-5 (RUBIES-UDS-170428) is best fit by metal-poor atmosphere models; both many be a thick disk or halo brown dwarfs. We critically examine the 1-5 $\mu$m spectra of the current sample of 1-2 kpc mid- and late-T dwarfs, finding that temperature, surface gravity, metallicity, and vertical mixing efficiency can all contribute to observed variations in near-infrared spectral structure and the strength of the 4.2 $\mu$m CO band. This work aims to guide ongoing JWST, Euclid, and other space-based spectral surveys that are expected to uncover thousands of low-temperature stars and brown dwarfs throughout the Milky Way.

Radio galaxy remnants are a rare subset of the radio-loud active galactic nuclei (RLAGN) population, representing the quiescent phase in the RLAGN lifecycle. Despite their observed scarcity, they offer valuable insights into the AGN duty cycle and feedback processes. Due to the mega-year timescales over which the RLAGN lifecycle takes place, it is impossible to observe the active to remnant transition in real-time. Numerical simulations offer a solution to follow the long-term evolution of RLAGN plasma. In this work, we present the largest suite (to date) of three-dimensional, hydrodynamic simulations studying the dynamic evolution of the active-to-remnant transition and explore the mechanisms driving cocoon evolution, comparing the results to the expectations of analytic modelling. Our results show key differences between active and remnant sources in both cluster environments and in lower-density group environments. We find that sources in low-density environments can remain overpressured well into the remnant phase. This significantly increases the time for the remnant lobe to transition to a buoyant regime. We compare our results with analytic expectations, showing that the long-term evolution of radio remnants can be well captured for remnants whose expansion is largely pressure-driven if the transition to a coasting phase is assumed to be gradual. We find that remnants of low-powered progenitors can continue to be momentum-driven for about 10 Myr after the jets switch-off. Finally, we consider how the properties of the progenitor influence the mixing of the remnant lobe and confirm the expectation that the remnants of high-powered sources have long-lasting shocks that can continue to heat the surrounding medium.

Fast Radio Bursts (FRBs) are enigmatic radio pulses whose origins are poorly understood. The dispersion measure of host galaxy (${\rm DM_{host}}$) provides critical insights into the local environment of FRB sources. In this study, we analyze a sample of 117 well-localized FRBs to investigate the statistical properties of ${\rm DM_{host}}$ and its potential correlations with host galaxy parameters, including redshift, stellar mass, star formation rate (SFR), and galaxy age. Our results reveal that ${\rm DM_{host}}$ is consistent with a log-normal distribution, with the mean $\mu_{\rm host}=5.03\pm 0.02$ and standard deviation $\sigma_{\rm host} = 0.96\pm 0.03$, which corresponds to a median value ${\rm Med}({\rm DM_{host}})=\exp(\mu_{\rm host})=153\pm 3~{\rm pc~cm^{-3}}$. We find a moderate positive correlation between ${\rm DM_{host}}$ and redshift, but no statistically significant correlations are found between ${\rm DM_{host}}$ and stellar mass, SFR, or galaxy age. Our findings highlight the importance of ${\rm DM_{host}}$ as a diagnostic tool for unraveling FRB origins, and underscore the need for future FRB surveys with deep multiwavelength host galaxy follow-up.

With seven temperate Earth-sized planets revolving around an ultracool red dwarf, the nearby TRAPPIST-1 system offers a unique opportunity to verify models of exoplanet composition, differentiation, and interior structure. In particular, the low bulk densities of the TRAPPIST-1 planets, compared to terrestrial planets in our solar system, require either substantial amount of volatiles to be present or a corefree scenario where the metallic core is fully oxidised. Here, using an updated metal-silicate partitioning model, we show that during core-mantle differentiation oxygen becomes more siderophile (iron-loving) implying larger planet radii. For the seven TRAPPIST-1 planets, however, we find that they are not sufficiently large to oxidise all the iron in the core, if they differentiate from an Earth-like composition. Oxygen partitioning in rocky worlds precludes coreless planets up to about 4 Earth masses. The observed density deficit in the TRAPPIST-1 planets, and more generally in M dwarf systems if confirmed by future observations, may be explained by system-dependent element budgets during planet formation, which are intrinsically linked to their stellar metallicity.

We present an analysis of the QUARKS survey sample, focusing on protoclusters where Hot Molecular Cores (HMCs, traced by CH3CN(12--11)) and UC HII regions (traced by H30\alpha/H40\alpha) coexist. Using the high-resolution, high-sensitivity 1.3 mm data from the QUARKS survey, we identify 125 Hot Molecular Fragments (HMFs), which represent the substructures of HMCs at higher resolution. From line integrated intensity maps of CH3CN(12--11) and H30\alpha, we resolve the spatial distribution of HMFs and UC HII regions. By combining with observations of CO outflows and 1.3 mm continuum, we classify HMFs into four types: HMFs associated with jet-like outflow, with wide-angle outflow, with non-detectable outflow, and shell-like HMFs near UC HII regions. This diversity possibly indicates that the hot core could be polymorphic and long-standing phenomenon in the evolution of massive protostars. The separation between HMFs and H30\alpha/H40\alpha emission suggests that sequential high-mass star formation within young protoclusters is not likely related to feedback mechanisms.

Precise estimation of cosmological parameters from the cosmic microwave background (CMB) remains a central goal of modern cosmology and a key test of inflationary physics. However, this task is fundamentally limited by strong foreground contamination, primarily from Galactic emissions, which obscure the faint CMB B-mode polarization signal. In this Letter, we introduce a fast, simulation-based, end to end pipeline that integrates a robust component separation technique with machine-learning, leading to cosmological parameter estimation. Our approach combines the Analytical Blind Separation (ABS) method for foreground removal with a neural network (NN) framework optimized to extract cosmological parameters directly from full-sky simulations. We assess the performance of this methodology for the forthcoming LiteBIRD and PICO satellite missions, designed to detect CMB B modes with unprecedented sensitivity. Applying the pipeline to realistic sky simulations, we obtain 1 sigma errors of 0.0035 (LiteBIRD) and 0.0030 (PICO) for the optical depth tau, and 0.005 (LiteBIRD) and 0.0014 (PICO) for the tensor-to-scalar ratio, r. In all cases, the recovered parameters are consistent with input values within 1 sigma across most of the parameter space. Results for LiteBIRD are in excellent agreement with the latest forecasts from the collaboration. Our findings establish this combined ABS-NN pipeline as a competitive, accurate, and computationally efficient alternative for cosmological parameter inference, offering a powerful framework for forthcoming CMB experiments.

Broad absorption line (BAL) quasars serve as critical probes for understanding active galactic nucleus (AGN) outflows, black hole accretion, and cosmic evolution. To address the limitations of manual classification in large-scale spectroscopic surveys - where the number of quasar spectra is growing exponentially - we propose BALNet, a deep learning approach consisting of a one-dimensional convolutional neural network (1D-CNN) and bidirectional long short-term memory (Bi-LSTM) networks to automatically detect BAL troughs in quasar spectra. BALNet enables both the identification of BAL quasars and the measurement of their BAL troughs. We construct a simulated dataset for training and testing by combining non-BAL quasar spectra and BAL troughs, both derived from SDSS DR16 observations. Experimental results in the testing set show that: (1) BAL trough detection achieves 83.0% completeness, 90.7% purity, and an F1-score of 86.7%; (2) BAL quasar classification achieves 90.8% completeness and 94.4% purity; (3) the predicted BAL velocities agree closely with simulated ground truth labels, confirming BALNet's robustness and accuracy. When applied to the SDSS DR16 data within the redshift range 1.5<z<5.7, at least one BAL trough is detected in 20.4% of spectra. Notably, more than a quarter of these are newly identified sources with significant absorption, 8.8% correspond to redshifted systems, and some narrow/weak absorption features were missed. BALNet greatly improves the efficiency of large-scale BAL trough detection and enables more effective scientific analysis of quasar spectra.

The most abundant type of planet discovered in the Galaxy has no analogue in our Solar System and is believed to consist of a rocky interior with an overlying thick H2 dominated envelope. Models have predicted that the reaction between the atmospheric hydrogen and the underlying magma ocean can lead to the production of significant amounts of water. The models suffer however from the current lack of experimental data on the reaction between hydrogen and silicate melt at high pressures and temperatures. Here we present novel experimental results designed to investigate this interaction. Laser heating diamond anvil cell experiments were conducted between 16 and 60 GPa at temperatures above 4000 K. We find that copious amounts of hydrogen dissolve into the silicate melt with a large dependence on temperature rather than pressure. We also find that the reduction of iron oxide leads to the production of significant amounts of water along with the formation of iron-enriched blebs. Altogether, the results predict that the typical processes attending planet formation will result in significant water production with repercussions for the chemistry and structure of the planetary interior as well as the atmosphere.

We report the results of the search for the high-energy neutrino emission associated with blazar flares, accounting for a possible lag of neutrinos with respect to the electromagnetic emission, either due to the slowness of the proton energy losses in $p\gamma$ collisions and/or proton acceleration. We perform two tests, cross-matching neutrinos with energies $E_{\nu} \gtrsim 100$~TeV from the public catalogue of neutrino alerts IceCat-1 with active galactic nuclei from two source samples based on 1) the MOJAVE database and 2) the CGRaBS catalogue, and utilising Fermi-LAT light curves from the public light curve repository. We scan over a wide range of values of the jet-frame time delay $t^{\prime}_{\mathrm{delay}}$ between the neutrino arrival and the time of the prior major $\gamma$-ray flare and find a pre-trial $\sim 2\sigma$ correlation at $t^{\prime}_{\mathrm{delay}} \sim 10^{3}$ d, which is consistent ($p_{\mathrm{post-trial}} \sim 0.1$) with expectations under the null hypothesis after trial correction.

Modelling of large-scale structure is increasingly concerned with galaxy assembly bias (GAB), the dependence of galaxy clustering on quantities other than halo mass. We investigate how baryonic physics affects the strength and redshift evolution of GAB using the largest runs of two state-of-the-art cosmological hydrodynamical simulations: SIMBA and IllustrisTNG. We quantify GAB by comparing the clustering of stellar-mass-selected galaxies to that of shuffled samples, where galaxies are randomly reassigned to haloes of similar mass. We find that GAB in both simulations increases from approximately zero at $z=5$ to a $\sim\,5\%$ change in clustering amplitude at $z=2$. After this epoch, the trends diverge: GAB in TNG continues to increase, reaching $\sim\,10\%$ at $z=0$, while in SIMBA it decreases to nearly zero. By further shuffling galaxies within bins of halo mass and cosmic environment -- characterised by smoothed matter overdensity ($\delta_5$) and tidal anisotropy ($\alpha_5$) -- we show that most of the GAB in both simulations can be attributed to the overdensity, while tidal anisotropy contributes negligibly in both simulations. Exploring this effect from the point of view of the halo occupation distribution (HOD), we find that numbers of central and satellite galaxies vary with overdensity -- but only near the respective turn-on masses for these two constituents: the galaxy contents of high-mass haloes are very nearly independent of environment. We present a simple parameterisation that allows the HOD modelling to be modified to reflect this form of density-dependent GAB.

The binary star MWC 656 was initially proposed as the first confirmed system composed of a Be star and a black hole. However, recent studies have challenged this interpretation, suggesting that the compact companion is unlikely to be a black hole. In this study, we revisit the nature of MWC 656 by analyzing archival data across multiple wavelengths, including radio observations from the VLA, optical astrometry from the Gaia satellite, and high-energy $\gamma$-ray data from the Fermi-LAT. Using all available VLA observations at X-band (8.0-12.0 GHz), we produce the deepest radio map toward this system to date, with a noise level of 780 nJy beam$^{-1}$. The source MWC 656 is detected with $S_\nu=4.6\pm0.8\mu$Jy and a spectral index of $\alpha=1.2\pm1.8$, derived by sub-band imaging. The radio and X-ray luminosity ratio of MWC 656 is consistent with both the fundamental plane of accreting black holes and with the Güdel-Benz relation for magnetically active stars, leaving the emission mechanism ambiguous. The optical astrometric results of MWC 656 indicate a peculiar velocity of $11.2\pm2.3$ km s$^{-1}$, discarding it as a runaway star. Its current location, 442 pc below the Galactic plane, implies a vertical travel time incompatible with the lifetime of a B1.5-type star. Moreover, the agreement between observed and expected motion in all three velocity components argues against a deceleration scenario, suggesting that MWC 656 likely formed in situ at high Galactic latitude. We carried out maximum likelihood analysis of Fermi-LAT data, but cannot report a significant detection of $\gamma$-ray emission from this source. These results reinforce recent evidence that challenge the black hole companion interpretation, and favor a non-BH compact object such as a white dwarf or neutron star.

Plasma flow measurements in solar active region filaments are rare, particularly in the infrared and ultraviolet ranges that probe the chromosphere and transition region. In addition, previous studies generally focused on prominences and filaments near the solar limb. This study presents a multi-wavelength, multi-instrument analysis of an active region filament observed on the solar disk on November 9 and 10, 2020. Our goal is to characterize the plasma flows in the filament using spectroscopic measurements in both the infrared and ultraviolet spectral ranges. This is important for understanding the mechanisms for filament support, mass loading, and energy balance. Furthermore, this also offers observational benchmarks for filament modeling and simulations. Spectra from the IRIS satellite, including the Mg II k, C II and Si IV lines were analyzed alongside ground-based observations from the GREGOR Infrared Spectrograph and High-resolution Fast Imager instruments whose observed spectral ranges include the chromospheric He I and H{\alpha} lines. Persistent blueshifts were measured within the filament structure in both spectral ranges. These can be interpreted as upflow velocities ranging from 0.5 to 15 km s^-1, with the Si IV showing the highest values. Red shifted emission in the He I and Mg II k3 at the footpoints of a newly formed dark bundle suggest chromospheric downflows, likely due to spatial overlap between an arch filament system close to the filament footpoints. The weak redshifted signal in the Si IV emission may suggest confinement to lower atmospheric layers. The observed velocity patterns provide, for the first time, a comprehensive and coherent view of the plasma dynamics from the chromosphere to the transition region, illustrating that the filament emission is consistently blueshifted in all the spectral windows, and thus in different temperature regimes.

We present a feature-based framework to anticipate Forbush decreases (FDs) from one-minute neutron-monitor data by tracking sliding-window invariants from information theory, scaling, and geometry. For each station and event, we compute marker series (Shannon, spectral, permutation, sample and approximate entropy; Lempel-Ziv complexity; Hurst via DFA; correlation dimension; Higuchi, Katz, and Petrosian fractal dimensions), smooth them with an exponentially weighted moving average, and analyze within-station standardized derivatives relative to the time of the minimum of the smoothed count derivative. Leads are reported in minutes (negative = precedes) and station-level significance is defined on a pre-onset window via a robust z-score detector with bilateral threshold and persistence; no cross-correlation or hypothesis testing is required. Applied to three recent FDs (2023-04-23, 2024-03-24, 2024-05-10), a compact, robust panel-Hurst (DFA), Katz fractal dimension, Shannon and sample entropy, and Lempel-Ziv-consistently precedes the count derivative with substantial station coverage, yielding actionable lead times from tens to several hundred minutes depending on morphology. Some descriptors are event-dependent: permutation and spectral entropy are strongly anticipatory in the extreme May 2024 episode but closer to contemporaneous in the rapid March 2024 case. Heatmaps, violin plots, and station overlays corroborate these patterns. The approach is reproducible from open code, operates on native station units without cross-station homogenization, and is qualitatively stable to window, smoothing, and detector settings. These results support derivative-aligned invariant panels as practical early-warning tools that complement amplitude thresholds and enable nowcasting workflows in space-weather operations.

In this work, we seek to characterise a large sample of 14377 main sequence eclipsing binaries in terms of their stellar, asteroseismic, and orbital properties. We conduct manual vetting on a 4000-target subset of our full 14377-target sample to identify targets with pressure or gravity modes. We infer stellar properties including the mass, convective core mass, radius, and central H fraction for the primary using Gaia Data Release 3 effective temperature and luminosity estimates and a grid of asteroseismically calibrated stellar models. We use surface brightness ratio and radius ratio estimates from previous eclipse analysis to study the effect of binarity on our results. Our manual vetting identifies 751 candidate g-mode pulsators, 131 p-mode pulsators, and a further 48 hybrid pulsators. The inferred stellar properties of the hybrid and p-mode pulsators are highly correlated, while the orbital properties of the hybrid pulsators align best with the g-mode pulsators. The g-mode pulsators themselves show a distribution that peaks around the classical g dor instability region but extends continuously towards higher masses, with no detectable divide between the classical g dor and SPB instability regions. There is evidence at the population level for a heightened level of tidal efficiency in stars showing g-mode or hybrid variability. Correcting the primary mass inference for binarity based on eclipse measurements of the surface brightness and radius ratios results in a relatively small shift towards lower masses. This work provides a working initial characterisation of this sample from which more detailed analyses folding in asteroseismic information can be built. It also provides a foundational understanding of the limitations and capabilities of this kind of rapid, scalable analysis that will be highly relevant in planning the exploitation of future large-scale binary surveys.

Joy's law is a well-established statistical property of solar active regions that any theory of active region emergence must explain. This tilt angle of the active region away from an east-west alignment is a critical component for converting the toroidal magnetic field to poloidal magnetic field in some leading dynamo theories, and observations show they are important for the reversal of the sign of the global solar magnetic dipole. This review aims to synthesise observational results related to the onset of Joy's law, placing them within the broader context that describes active region emergence as a largely passive process occurring near the surface of the Sun.

One of the most efficient and reliable observational technique allowing to probe the internal structure of a star is the determination of the apsidal motion in close eccentric binaries. This secular precession of the binary orbit's major axis depends on the tidal interactions occurring between the two stars. Its rate is directly related to the internal structure of the stars, in particular their inner density profile. Combining radial velocity and light curve data over a long timescale, the apsidal motion rate can be constrained, together with the fundamental parameters of the stars. Confrontation of observational parameters to stellar models then allows us to constrain the internal structure of stars. This powerful technique has been known for years but has been seldom applied to massive stars. I highlight its interest and reveal recent results concerning several massive binaries. While standard stellar models predict stars having a smaller internal stellar structure constant, that is to say, stars having a smaller density contrast, than expected from observations, I demonstrate that the addition of mixing inside the models helps to solve, at least partially, this discrepancy. Studies with the non-perturbative code MoBiDICT showed that the perturbative model assumption is not justified in highly distorted stars, in which cases the apsidal motion is underestimated, exacerbating even more the need for enhanced mixing inside the models. But what happens if the binary is a double-line spectroscopic but non-eclipsing binary? In that case, we indeed have no estimate of the masses and radii of the stars. Surprisingly, the apsidal motion equations combined with the binary' spectroscopic observations allow us to derive the masses of the stars, in a model-dependent way. Rodolfo Barbá contributed to the development of this original method that I bring out.

As a space telescope, the China Space Station Survey Telescope (CSST) will face significant challenges from cosmic ray (CR) contamination. These CRs will severely degrade image quality and further influence scientific analysis. Due to the CSST's sky survey strategy, traditional multi-frame stacking methods become invalid. The limited revisits prompted us to develop an effective single-image CR processing method for CSST. We retrained the DeepCR model based on CSST simulated images and achieved 97.90+-0.18% recall and 98.67+-0.05% precision on CR detection. Moreover, this paper puts forward an innovative morphology-sensitive inpainting method, which focuses more on areas with higher scientific value. We trained a UNet++ model especially on contaminated stellar/galactic areas, alongside adaptive median filtering for background regions. This method achieves effective for CRs with different intensities and different distances from centers of scientific targets. By this approach, the photometric errors of CR-corrected targets could be restricted to the level comparable to those of uncontaminated sources. Also, it increases the detection rate by 13.6% compared to CR masking. This method will provide a robust CR mitigation for next-generation space telescopes.

Space missions (CHEOPS, JWST, PLATO) facilitate detailed characterization of exoplanets. This work provides a framework to characterize cloud and climate properties of close-in gas giants via transit depth asymmetries from the optical to the infrared (0.33 ...10 $\mu$m). The AFGKM ExoRad 3D GCM grid provides gas temperature profiles for an ensemble of 50 tidally locked gaseous planets orbiting diverse host stars. It is combined with a detailed kinetic cloud formation model. The end result is a set of synthetic transit spectra and evening-to-morning transit asymmetries that span climate regimes: warm (T=800 K ... 1000K), intermediately hot (T=1200 K ... 2000 K) and ultrahot (T =2200 K ... 2600 K). WASP-39b observations suggest iron-free clouds with less abundant cloud condensation nuclei than previously expected. The ensemble study shows that clouds increase transit limb differences due to asymmetries in cloud coverage and by enhancing horizontal differences in the gas temperatures. For hot planets, evening-to-morning differences of up to 150 ppm are suggested in the optical and 100 ppm in the infrared (2-8 micron). For ultra-hot Jupiters, evening-to-morning transit differences are dominated by the morning cloud for a cloud-free evening limb: They are strongly negative in the PLATO band (0.5-1~$\mu$m, -500 ppm), moderately negative in the near-infrared (1-1.5~$\mu$m, -200 ppm) and moderately positive (+100 ppm) for $\lambda > 2\mu$m. For a partly cloudy evening terminator, the evening-to-morning transit asymmetry is moderately positive in the whole wavelength range. Warm Jupiter planets exhibit negligible transit asymmetries. PLATO and JWST transit asymmetry observations between 1-2 $\mu$m are optimal to characterize cloudy planetary atmospheres around K -A stars. JWST observations are most effective for M star planets with transit differences > +500 ppm for 8-10 $\mu$m.

We investigate the spatial distribution of the Intra-Cluster Globular Clusters (ICGCs) detected in the core of the Fornax galaxy cluster. By separately modeling different components of the observed population of Globular Clusters (GCs), we confirm the existence of an abundant ICGCs over-density with a geometrically complex, elongated morphology roughly centered on the cluster dominant galaxy NGC 1399 and stretching along the E-W direction. We identify several areas in the ICGCs distribution that deviate from a simple elliptical model and feature large density enhancements. These regions are characterized based on their statistical significance, GCs excess number, position, size and location relative to the galaxies in their surroundings. The relations between the spatial distribution and features of the ICGCs structures, mostly populated by blue GCs, and properties of the intra-cluster light and dwarf galaxies detected in the core of the Fornax cluster are described and discussed. The line-of-sight velocity distribution of spectroscopically confirmed GCs within the ICGCs structures is compatible with the systemic velocities of nearby bright galaxies in the Fornax cluster, suggesting that the ICGCs population is at least partially composed of GCs stripped from their hosts. We argue that the findings here presented suggest that, on sub-cluster scales, different mechanisms contribute to the growth of the ICGC. The western region of Fornax is likely associated with old merging events that predate the assembly of the Fornax cluster. The eastern side instead points to a mix of tidal disruption of dwarf galaxies and stripping from the GCSs of massive hosts, more typical of relaxed, high-density cluster environments.

Horizontally-periodic Boussinesq Rayleigh-Bénard Convection (RBC) is a simple model system to study the formation of large-scale structures in turbulent convective flows. We performed a suite of 2D numerical simulations of RBC between no-slip boundaries at different Prandtl (Pr) and Rayleigh (Ra) numbers, such that their product is representative of the Sun's upper convection zone. When the fluid viscosity is sufficiently low (Pr $\lesssim 0.1$) and turbulence is strong (Ra $> 10^6$) we find that large structures begin to couple in time and space. For Pr = 0.01 we observe long-lived swaying oscillations of the upflows and downflows, which synchronize over multiple convection cells. This new regime of oscillatory convection may offer an interpretation for the wave-like properties of the dominant scale of convection on the Sun (supergranulation).

$\mbox{H}$ $\mbox{I}$ 21-cm absorption, an extremely useful tool to study the cold atomic hydrogen gas, can arise either from the intervening galaxies along the line-of-sight towards the background radio source or from the radio source itself. Determining whether $\mbox{H}$ $\mbox{I}$ 21-cm absorption lines detected as part of large, blind surveys are `intervening' or `associated' using optical spectroscopy would be unfeasible. We therefore investigate a more efficient, machine learning (ML)-based method to classify $\mbox{H}$ $\mbox{I}$ 21-cm absorption lines. Using a sample of 118 known $\mbox{H}$ $\mbox{I}$ 21-cm absorption lines from the literature, we train six ML models (Gaussian naive Bayes, logistic regression, decision tree, random forest, SVM and XGBoost) on the spectral parameters obtained by fitting the Busy function to the absorption spectra. We found that a random forest model trained on these spectral parameters gives the most reliable classification results, with an accuracy of 89%, a $F_1$-score of 0.9 and an AUC score of 0.94. We note that the linewidth parameter $w_{20}$ is the most significant spectral parameter that regulates the classification performance of this model. Retraining this random forest model only with this linewidth and the integrated optical depth parameters yields an accuracy of 88%, a $F_1$-score of 0.88 and an AUC score of 0.91. We have applied this retrained random forest model to predict the type of 30 new $\mbox{H}$ $\mbox{I}$ 21-cm absorption lines detected in recent blind surveys, viz. FLASH, illustrating the potential of the techniques developed in this work for future large $\mbox{H}$ $\mbox{I}$ surveys with the Square Kilometre Array.

Exoplanet direct imaging allows us to directly probe and characterize an exoplanet's atmosphere, searching for signs of life in its atmospheric signatures. Directly imaging an Earth-like planet around a Sun-like star requires reaching 10$^{-10}$ contrast levels and will be the goal of the Habitable Worlds Observatory (HWO). A key technical barrier to reaching such deep contrasts is maintaining wavefront stability on the order of tens of picometers, in particular in the presence of a segmented primary mirror. Keck Observatory is the only facility with all of the hardware components necessary for validating HWO segment phasing strategies: a large segmented primary mirror, capacitive edge sensors, deformable mirror, Zernike wavefront sensor (ZWFS), and high contrast science instruments. Taking advantage of these parallels, we are using Keck as a testbed for developing and validating HWO wavefront sensing and control loop strategies, as well as demonstrating the full system-level segment control architecture for HWO, using existing infrastructure. Recently, we set the stage for this work by using the ZWFS installed on the Keck II telescope to sense and correct the primary mirror segment pistons in closed-loop in parallel with science observations. This resulted in improved Strehl ratios on the NIRC2 science camera (Salama et al. 2024a). We now aim to directly address concerns related to control authority, actuator offload, and loop stability - tasks which require Keck's existing infrastructure, but which do not require picometer wavefront stability. Moreover, successful comparisons of observed and predicted performances will validate, on a real operating observatory, the HWO error budget methodology and in particular its approach to nested loops operating at multiple timescales.

The Transiting Exoplanet Survey Satellite (TESS) has discovered over 6700 nearby exoplanets candidates using the transit method through its all-sky survey. Characterizing the kinematic properties and identifying variable stars for the TESS stellar sample is crucial for revealing the correlations between the properties of planetary systems and the properties of stars (e.g., Galactic components, age, chemistry, dynamics, radiation). Based on data from TESS, Gaia DR3, and LAMOST DR10, we present a catalog of kinematic properties (i.e., Galactic positions, velocities, orbits, Galactic components, and kinematic age) as well as other basic stellar parameters for $\sim 660,000$ TESS stars. Our analysis of the kinematic catalog reveals that stars belonging to different Galactic components (i.e., thin disk, thick disk, halo and 12 streams in the disk) display distinctive kinematic and chemical properties. We also find that hot planets with period less then 10 days in the TESS sample favor thin disk stars compared to thick disk stars, consistent with previous studies. Furthermore, using the LAMOST multiple-epoch observations, we identify 41,445 stars exhibiting significant radial velocity variations, among which 7,846 are classified as binary stars. By fitting the radial velocity curves, we further derive orbital parameters (e.g., mass ratio, orbital period and eccentricity) for 297 binaries. The observed decreasing orbital eccentricity with shorting period reveals evidence of tidal circularization. The catalogs constructed in this work have laid a solid foundation for future work on the formation and evolution of stellar and planetary systems in different Galactic environments.

We conducted a detailed spectroscopic and photometric characterization of the planet-hosting wide binary HD 202772A/B. No planet has been detected around HD 202772B, whereas HD 202772A, more evolved than its companion and near the end of its main-sequence (MS) phase, hosts a transiting hot Jupiter. The system has one of the hottest components ($T_{\mathrm{eff}; A} \sim 6440$ K) and one of the largest surface gravity differences between components ($\Delta\log g_{A-B} \sim 0.4$ dex) among MS planet-hosting wide binaries. Using a global fit including our stellar parameters, radial velocities, and new TESS data, we derive refined properties of the planet orbiting HD 202772A, finding it to be the most irradiated hot Jupiter known in a wide binary. We also constrain the presence of additional transiting planets around HD 202772A and new transiting planets around HD 202772B using TESS photometry. We derive high-precision, strictly differential abundances for 27 species based on Gemini-GRACES spectra. HD 202772A shows lower lithium abundance (by 0.45 dex) relative to B, consistent with their stellar parameter differences. We also detect a small but significant enhancement in refractory elements in HD 202772A, particularly those with condensation temperatures above 1400 K (+0.018 $\pm$ 0.004 dex). We explored several scenarios to explain the observed chemical anomalies. Our analysis suggests that rocky planet engulfment, primordial inhomogeneities, and $\delta$ Scuti-related effects are unlikely to fully account for the chemical pattern. Instead, the differences observed in certain refractory elements might support atomic diffusion as the most plausible explanation.

We investigate the evolution of interplanetary coronal mass ejection (ICME) sheath regions at 1 AU across solar cycles 23, 24, and the rising phase of 25, focusing on their variability and turbulence in relation to upstream solar wind conditions and the global heliospheric state. Using a dataset of over 900 ICME sheath events, we apply statistical metrics such as the interquartile range (IQR) and the Turbulence Index (TI) to quantify variability and turbulence. The analysis compares full and rising phases of solar cycles and examines both local ICME parameters (e.g., sheath total pressure, non-radial flows) and global interplanetary indicators such as open solar flux (OSF). From SC23 to SC24, sheath total pressure and magnetic field strength decreased by over 40% and 25%, respectively, accompanied by reduced turbulence and variability. In contrast, the rising phase of SC25 shows increased magnetic complexity, particularly in non-radial field components, despite stable bulk parameters. Non-radial flow patterns also shift from tangentially dominated in SC23-SC24 to normal-dominated in SC25, suggesting changes in ICME orientation and sheath formation mechanisms. No significant correlation is found between OSF and sheath properties, indicating that local solar wind and ICME specific factors are the primary drivers of sheath evolution. The study reinforces the importance of upstream solar wind dynamics in relation to variations in plasma and magnetic field measured components of ICME sheaths. The derived trends in turbulence, magnetic orientation, and flow geometry suggest that sheath regions are sensitive indicators of solar cycle phase and should be considered as distinct, structured components in ICME modeling.

We present new constraints on the scale dependence of the primordial power spectrum by combining Planck, ACT DR6, SPT-3G and eBOSS Lyman-$\alpha$ forest data, extending sensitivity to smaller comoving scales. While ACT results previously indicated a mild preference for positive running of the spectral index, our joint analysis constrains both the running $\alpha_s$ and its running $\beta_s$. Including eBOSS markedly tightens these constraints, yielding a $>2\sigma$ indication of nonzero $\alpha_s$ and/or $\beta_s$, challenging predictions from vanilla slow-roll inflation potentials. Comparing reconstructed spectral parameters with theoretical models, we find that inflationary potentials with localised dips, bumps, or oscillations better reproduce the observed scale dependence. We release the public PIPE code to test arbitrary inflationary potentials against these datasets.

We investigate the feasibility of detecting extensive air showers via their geo-synchrotron X-ray emission from high-altitude platforms. Starting from first principles, we derive a differential expression for the number of emitted photons per unit grammage and photon energy for an ensemble of gyrating shower electrons. The calculation uses noted parameterizations of the electron state variable distributions in the shower to establish a scale for the photon footprint and, further, takes into account the propagation of emitted photons in the atmosphere. The computed fluxes at the position of the detector are used to estimate the detector acceptance and event rate using a bootstrap Monte Carlo procedure. For a 1 m radius and 70° half-aperture circular detector at an altitude between 20 to 30 km viewing the Earth's limb, we find acceptances at the 1 $\mathrm{m^2 sr}$ level and integral event rates of roughly 10 per month. These results indicate that X-ray geo-synchrotron emission is a promising, complimentary channel for high-altitude indirect cosmic ray detection in the PeV regime.

A major attraction of diffusive shock acceleration is the prediction of power-law spectra for energetic particle distributions. However, this property is not fundamental to the theory. We demonstrate that for planar shocks with an oblique magnetic field the generation of power-law spectra critically requires the particles' scattering rate to be both directly proportional to their gyro radius (Bohm scaling) and spatially uniform. Non-Bohm scaling results in curved spectra at oblique shocks, while abrupt changes in the spatial profile of the scattering upstream introduces spectral breaks. Using the publicly available code Sapphire++, we numerically explore the magnitude of these effects, which are particularly pronounced at fast shocks, as expected in active galactic nuclei and microquasar jets, or young supernova remnants.

A decrease in the orbital period of the ultrashort-period binary white dwarf \ZTF, which is one of the Galactic verification binaries in the millihertz frequency range for planned space laser interferometers, has been measured. Based on photometric observations carried out on the 2.5-m telescope of the Caucasian Mountain Observatory of the Sternberg Astronomical Institute of Moscow State University (CMO SAI MSU), a diagram \textit{O-C} is constructed. It can be described by quadratic elements of the brightness variation, which correspond to a decrease rate of the orbital period of the system of $dP/dt=-(1.16\pm 0.22)\times 10^{-11}$ s/s. The decrease rate of the orbital period in the quadrupole approximation for the emission of gravitational waves by a binary system corresponds to its chirp mass $\mathcal{M}=0.434\pm 0.05 M_\odot$, which turned out to be $\sim 30\%$ higher than the value obtained earlier from spectroscopic mass determination. The chirp mass of \ZTF inferred from the measured orbital decay rate makes this system the brightest Galactic verification binary for LISA and TianQin space interferometers with a signal-to-noise ratio of $\approx 119$ and $\approx 30$ over 5 years and 2.5 years of observations, respectively.

We report the first results from observations of the solar corona by the ASPIICS coronagraph aboard the Proba-3 mission. ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun) is a giant coronagraph consisting of the telescope mounted aboard one of the mission's spacecraft and the external occulter placed on the second spacecraft. The two spacecraft separated by around 144 m fly in a precise formation up to 5.5 hours at a time, which allows coronal observations in eclipse-like conditions, i.e. close to the limb (typically down to 1.099 Rs, occasionally down to 1.05 Rs) and with very low straylight. ASPIICS observes quasi-stationary structures, such as coronal loops, streamers, quiescent prominences, and a variety of dynamic phenomena: erupting prominences, coronal mass ejections, jets, slow solar wind outflows, coronal inflows. In particular, weak, widespread and persistent small-scale outflows and inflows between 1.3 and 3 Rs are observed at a high spatial (5.6 arcsec) and temporal (30 s) resolution for the first time, expanding the range of scales at which the variable slow solar wind is observed to form.

The diffuse emission of gamma-rays and neutrinos, produced by interactions of cosmic rays with interstellar matter in the Milky Way, provides valuable insights into cosmic ray propagation and Galactic processes. Emission models incorporating different assumptions about cosmic ray diffusion, source distribution, and target gas density are tested using data from neutrino telescopes. In this study, the final all-flavor neutrino dataset, collected over 15 years (2007--2022) by the ANTARES neutrino telescope, is analyzed. A maximum likelihood ratio method built to handle templates of Galactic emission models is employed to evaluate the compatibility of these models with the observed spatial and energy distributions of neutrino events. The results do not yield stringent constraints on the tested models and upper limits on the diffuse neutrino flux are derived, which are compatible with the results obtained by other experiments.

In this paper, we emphasise the recent observational findings from the Dark Energy Spectroscopic Instrument Data Release 2 (DESI DR2), which provide compelling evidence for a possible deviation from the standard $\Lambda$CDM (Cold Dark Matter) cosmology, suggesting the presence of a dynamically evolving effective dark energy component. Motivated by this, we construct a theoretical framework in which a massive cosmological vector field, $B^{\mu}$, couples non-minimally to the background curvature through marginal interactions, offering a controlled mechanism to realise the deviation from the $\Lambda$CDM model. A detailed analysis of the effective Equation of State (EoS) parameter $w(\tilde H)$ reveals a narrow region of parameter space consistent with current cosmological observations presented by DESI. The analysis yields a stringent upper bound for the coupling constant $\lambda$ to be $\lambda<2.98\times10^{-11}$, a very strong bound on mass $3.1356\times10^{-66}~\text{g} \leq m \leq 3.3627\times10^{-66}~\text{g},$ and the admissible range $-0.405 \leq \log_{10}\tilde\gamma \leq -0.38$ for which present-day value $w_0 = w(\tilde H = 1)$ corresponding to a deviation $\delta = w_0 + 1$ that lies within the region $0.107 \leq \delta \leq 0.217$. This interval reproduces the deviation inferred from the combined DESI, Cosmic Microwave Background (CMB), and Pantheon+ data, reflecting a controlled departure from the $\Lambda$CDM behaviour. In summary, the results suggest that the proposed framework of a massive vector field can account for the departure from $\Lambda$CDM behaviour highlighted by DESI in the current cosmic acceleration. Furthermore, the framework approaches the $\Lambda$CDM behaviour in late-time $t\gtrsim28$ Gyr, establishing a direct phenomenological link between the underlying parameters and the observed dynamical nature of dark energy.

The CCAT Observatory's Fred Young Submillimeter Telescope, a novel, high-throughput, 6-meter aperture telescope, is scheduled for first light in 2026. Located at 5600 m on Cerro Chajnantor in the Chilean Atacama Desert, the CCAT site enables unprecedented submillimeter measurement capabilities, fully overlapping with millimeter-wave surveys like the Simons Observatory. CCAT will address a suite of science goals, from Big Bang cosmology, star formation, and line-intensity mapping of cosmic reionization, to galactic magnetic fields, transients, and galaxy evolution over cosmic time. We highlight CCAT's science goals with Prime-Cam, a first generation science instrument for the Fred Young Submillimeter Telescope. Prime-Cam will field over 100,000 kinetic inductance detectors across seven instrument modules to enable over ten times faster mapping speed than previous submillimeter observatories in windows between 1.4 - 0.3 mm (220 - 850 GHz). We give an instrument summary, discuss the project status, and outline preliminary plans for early science.

Over 20 exocometary belts host detectable circumstellar gas, mostly in the form of CO. Two competing theories for its origin have emerged, positing the gas to be primordial or secondary. Primordial gas survives from the belt's parent protoplanetary disk and is therefore H$_2$-rich. Secondary gas is outgassed \textit{in-situ} by exocomets and is relatively H$_2$-poor. Discriminating between these scenarios has not been possible for belts hosting unexpectedly large quantities of CO. We aim to break this gas origin dichotomy \textit{via} direct measurement of H$_2$ column densities in two edge-on CO-rich exocometary belts around $\sim$15 Myr-old A-type stars, constraining the $\frac{\text{CO}}{\text{H}_2}$ ratio and CO gas lifetimes. Observing edge-on belts enables rovibrational absorption spectroscopy against the stellar background. We present near-IR CRIRES+ spectra of HD 110058 and HD 131488 which provide the first direct probe of H$_2$ gas in CO-rich exocometary belts. We target the H$_2$ (v=1-0 S(0)) line at 2223.3 nm and and the $^{12}$CO $v=2\rightarrow0$ rovibrational lines in the range 2333.8-2335.5 nm and derive constraints on column densities along the line-of-sight to the stars. We strongly detect $^{12}$CO but not H$_2$ in the CRIRES+ spectra. This allows us to place $3\sigma$ lower limits on the $\frac{\text{CO}}{\text{H}_2}$ ratios of $> 1.35 \times 10^{-3}$ and $> 3.09 \times 10^{-5}$ for HD 110058 and HD 131488 respectively. These constraints demonstrate that at least for HD 110058, the exocometary gas is compositionally distinct and significantly H$_2$-poor, compared to the $<10^{-4}$ $\frac{\text{CO}}{\text{H}_2}$ ratios typical of protoplanetary disks. We also find H$_2$ alone is unlikely to shield CO over the lifetime of the systems. Overall this suggests that the gas in CO-rich belts is most likely not primordial in origin, supporting the presence of exocometary gas.

Neutral atomic hydrogen (HI) constitutes a key phase of the cosmic baryon cycle, bridging the ionised circumgalactic medium and the star-forming molecular gas. Yet, nearly 75 years after its discovery, direct views of HI through its 21cm emission line remain largely confined to the nearby Universe. Indirect measurements and statistical analyses indicate little evolution in the comoving HI density over the past 10 billion years, in stark contrast to the order-of-magnitude decline in the cosmic star-formation rate density over the same epoch. Resolving this tension requires direct HI measurements in individual, representative galaxies at earlier times. Here we report a detection of HI 21cm emission from the Dragon Arc, a gravitationally lensed main-sequence star-forming galaxy at $z=0.725$, observed 6.6 billion years in the past with the MeerKAT radio telescope. The inferred intrinsic HI mass, $M_{\rm HI}=10^{9.66^{+0.16}_{-0.19}}\,\mathrm{M}_\odot$, and velocity width of $205^{+66}_{-48}\,\mathrm{km\,s^{-1}}$ are consistent with expectations from scaling relations for local star-forming galaxies. The resulting HI depletion time of $1.2^{+1.0}_{-0.6}\,\mathrm{Gyr}$ is significantly shorter than the $\sim5-10$ Gyr, measured locally for comparable galaxies. This indicates that the galaxy must rapidly replenish its atomic gas reservoir to remain on the star-forming main sequence. This detection demonstrates that strong gravitational lensing, combined with modern cm-wave facilities, can now reveal the HI reservoirs of typical galaxies well beyond the local Universe, opening a new path toward statistical samples that will directly trace the evolution of the cosmic atomic gas supply.

We present near-infrared scattered-light observations of the disks around two stars of the Corona Australis star-forming region, V721 CrA, and BN CrA, obtained with VLT/SPHERE, in the H band, as part of the DESTINYS large programme. Our objective is to analyse the morphology of these disks, and highlight their main properties. We adopt an analytical axisymmetric disk model to fit the observations and perform a regression on key disk parameters, namely the dust mass, the height profile, and the inclination. We use RADMC-3D code to produce synthetic observations of the analytical models, with full polarised scattering treatment. Both stars show resolved and extended disks with substructures in the near-IR. The disk of V721 CrA is vertically thicker, radially smaller (120 au), and brighter than BN CrA (190 au). It also shows spiral arms in the inner regions. The disk of BN CrA shows a dark circular lane, which could be either an intrinsic dust gap or a self-cast shadow, and a brightness enhancement along the disk minor axis. Both disks are compatible with the evolutionary stage of their parent subgroup within the CrA region: V721 CrA belongs to the "on-cloud" part of CrA, which is dustier, denser and younger, whereas BN CrA is found on the outskirts of the older "off-cloud" group.

The production sites of high-energy astrophysical neutrinos remain uncertain, though growing evidence suggests a connection to relativistic jets in active galactic nuclei (AGN). We present a detailed analysis of the recent PeV neutrino event KM3-230213A reported by the KM3NeT collaboration, aiming to constrain the physical conditions of its source. Assuming proton acceleration at shocks, we derive the properties of the proton distribution and the energetics required to explain the neutrino emission. Using contemporaneous multiwavelength observations of three AGN flaring candidates within the error region, we examine the plausibility of each of them as the possible counterpart. Our results favor PMN J0606-0724, which exhibits a prominent radio flare coincident with the neutrino arrival. In this framework, the red-giant interaction remains the key driver of baryon injection and shock acceleration, while the dominant external photon field sets the neutrino energy scale: photospheric photons from the red giant yield ~1-10 PeV neutrinos, whereas the ~220 PeV event KM3-230213A is more naturally produced through interactions with colder infrared photons from the dusty torus.

Characterising the relationship between dense gas and star formation is critical for understanding the assembly of galaxies throughout cosmic history. However, due to the faintness of standard dense-gas tracers - HCN, HCO+, and HNC - dense gas in high-redshift galaxies remains largely unexplored. We present ALMA and NOEMA observations targeting HCN/HCO+/HNC (3-2) and (4-3) emission lines in eleven (mostly) gravitationally lensed dusty star-forming galaxies (DSFGs) at redshift z = 1.6--3.2. We detect at least one line in 10 out of 11 galaxies. Altogether, we detect 34 dense-gas transitions, more than quadrupling the number of extant high-redshift detections. Additionally, in two targets, we detect lower-abundance CO isotopologues 13^CO and C^18O, as well as CN emission. We derive excitation coefficients for HCN, HCO+ and HNC in DSFGs, finding them to be systematically higher than those in nearby luminous infrared galaxies. Assuming a canonical dense-mass conversion factor (alpha_HCN = 10), we find that DSFGs have shorter dense- gas depletion times (median 23 Myr) than nearby galaxies (~60 Myr), with a star-forming efficiency per free-fall time of 1-2%, a factor of a few higher than in local galaxies. We find a wide range of dense-gas fractions, with HCN/CO ratios ranging between 0.01 and 0.15. Finally, we put the first constraints on the redshift evolution of the cosmic dense-gas density, which increases by a factor of 7+/-4 between z = 0 and z = 2.5, consistent with the evolution of the cosmic molecular-gas density.

The scale of the seesaw mechanism is typically much larger than the electroweak scale. This hierarchy can be naturally explained by $U(1)_{B-L}$ symmetry, which after spontaneous symmetry breaking, simultaneously generates Majorana masses for neutrinos and produces a network of cosmic strings. Such strings generate a gravitational wave (GW) spectrum which is expected to be almost uniform in frequency unless there is a departure from the usual early radiation domination. We explore this possibility in Type I, II and III seesaw frameworks, finding that only for Type-I, long-lived right-handed neutrinos (RHN) may provide a period of early matter domination for parts of the parameter space, even if they are thermally produced. Such a period leaves distinctive imprints in the GW spectrum in the form of characteristic breaks and a knee feature, arising due to the end and start of the periods of RHN domination. These features, if detected, directly determine the mass $M$, and effective neutrino mass $\tilde m$ of the dominating RHN. We find that GW detectors like LISA and ET could probe RHN masses in the range $M\in[0.1,10^{9}]$ GeV and effective neutrino masses in the $\tilde m\in[10^{-10},10^{-8}]$ eV range. We investigate the phenomenological implications of long-lived right-handed neutrinos for both local and global $U(1)_{B-L}$ strings, focusing on dark matter production and leptogenesis. We map the viable and detectable parameter space for successful baryogenesis and asymmetric dark matter production from right-handed neutrino decays. We derive analytical and semi-analytical relations correlating the characteristic gravitational-wave frequencies to the neutrino parameters $\tilde m$ and $M$, as well as to the relic abundances of dark matter and baryons.

Nuclear star clusters represent some of the most extreme collisional environments in the Universe. A typical nuclear star cluster harbors a supermassive black hole at its center, which accelerates stars to high speeds ($\gtrsim 100$-$1000$ km/s) in a region where millions of other stars reside. Direct collisions occur frequently in such high-density environments, where they can shape the stellar populations and drive the evolution of the cluster. We present a suite of a couple hundred high-resolution smoothed-particle hydrodynamics (SPH) simulations of collisions between $1$ M$_\odot$ stars, at impact speeds representative of galactic nuclei. We use our SPH dataset to develop physically-motivated fitting formulae for predicting collision outcomes. While collision-driven mass loss has been examined in detail in the literature, we present a new framework for understanding the effects of "hit-and-run" collisions on a star's trajectory. We demonstrate that the change in stellar velocity follows the tidal-dissipation limit for grazing encounters, while the deflection angle is well-approximated by point-particle dynamics for periapses $\gtrsim0.3$ times the stellar radii. We use our SPH dataset to test two machine learning (ML) algorithms, k-Nearest Neighbors and neural networks, for predicting collision outcomes and properties. We find that the neural network out-performs k-Nearest Neighbors and delivers results on par with and in some cases exceeding the accuracy of our fitting formulae. We conclude that both fitting formulae and ML have merits for modeling collisions in dense stellar environments, however ML may prove more effective as the parameter space of initial conditions expands.

The current cosmological paradigm, $\Lambda$CDM, is characterized its expansive description of the history of the Universe, its deep connections to particle physics and the large amounts of data that support it. Nonetheless, $\Lambda$CDM's critics and boosters alike agree on one thing: it is the not the final cosmological theory and they are anxious to see it replaced by something better! After reviewing some of the impactful events in cosmology since the last \Le Workshop, I focus on the role that the recent evidence for evolving dark energy may play in getting cosmology that better theory.

The equation of state of dense matter remains a central challenge in astrophysics and high-energy physics, particularly at supra-nuclear densities where exotic degrees of freedom like hyperons or deconfined quarks are expected to appear. Neutron stars provide a unique natural laboratory to probe this regime. In this work, we present EVA--01, a novel equation of state that provides a unified description of dense matter by incorporating both hadron and quark degrees of freedom within a single relativistic mean-field Lagrangian, from which the equation of state is derived at finite temperature. The model extends the density-dependent formalism by introducing a Polyakov-loop-inspired scalar field to dynamically govern the hadron-quark phase transition, following the approach of chiral mean-field models. The resulting model is consistent with a wide range of theoretical and observational constraints, including those from chiral effective field theory, massive pulsars, gravitational-wave events, and NICER data. We analyze its thermodynamic properties by constructing the QCD phase diagram, identifying the deconfinement, chiral, and nuclear liquid-gas transitions. As a first application, we model the evolution of proto-neutron stars using isentropic snapshots and explore the implications of the slow stable hybrid star hypothesis. Our findings establish EVA--01 as a robust and versatile framework for exploring dense matter, bridging the gap between microphysical models and multimessenger astrophysical observations.

Mercury's core mass fraction (CMF) is ~0.7, more than double that of the other rocky planets in the solar system, which have CMFs of ~0.3. The origin of Mercury's large, iron-rich core remains unknown. Adding to this mystery, an elusive population of "Exo-Mercuries" with high densities is emerging. Therefore, understanding the formation of Mercury and its exoplanetary analogs is essential to developing a comprehensive planet formation theory. Two hypotheses have been proposed to explain the high CMF of Mercury: (1) giant impacts during the latest stages of planet formation strip away mantle layers, leaving Mercury with a large core; and (2) earlier-stage iron enrichment of planetesimals closer to the Sun leads to the formation of an iron-rich planet. In this work, we conduct N-body simulations to test these two possibilities. Our simulations are focused on the solar system, however, we aim to provide a framework that can later be applied to the formation of high-CMF exoplanets. To investigate the giant impact scenario, we employ uniform initial CMF distributions. To address the other hypothesis, we use a step function with higher CMFs in the inner region. For a uniform initial CMF distribution, our results indicate that although erosive impacts produce iron-rich particles, without mechanisms that deplete stripped mantle material, these particles merge with lower-CMF objects and do not lead to Mercury's elevated CMF. However, a step function initial CMF distribution leads to the formation of a high-CMF planet alongside Earth-like planets, resembling the architecture of the terrestrial solar system.

The solar chromosphere is a crucial interface between the solar interior and its interplanetary environment, regulating how energy is locally deposited into heat and transported into the upper atmospheric layers. Despite significant progress, the dominant processes responsible for chromospheric heating remain debated, particularly under quiet-Sun (QS) conditions. We aim to disentangle and quantify the respective roles of shocks and current sheets (CS) in QS chromospheric modeling. We use a simulation performed with the radiation-magnetohydrodynamics code Bifrost. In order to identify shocks and CS events across space and time, we develop and apply physics-based criteria, allowing us to describe their dynamics and evaluate their contributions to both dissipative (viscous and ohmic) and mechanical (including compressive work) heating. Shocks are found to dominate the energy deposition in the lower chromosphere (up to $59\%$ of the mechanical heating), while CS become the primary contributor in the upper chromosphere, as both plasma $\beta$ and Mach number $Ma$ drop. Overall, $66\%$ of the mechanical chromospheric heating is powered by the combined action of shocks and CS. These results support a multi-process view of the chromospheric heating in the QS, dominated by shocks, CS, and non-steep gradient dynamics. In addition to viscous and ohmic dissipation, compressive heating can play a major role locally in the model, particularly in chromospheric shock structures, where it offsets non-reversibly cooling from expansion and radiation, and therefore constitutes a key heating contribution to consider in the energy budget. This study further highlights the need for next-generation observations to resolve the intermittent and small-scale nature of chromospheric dynamics, in order to bring new constraints on the coupling between the different layers of the solar atmosphere.

Core-collapse supernovae, occurring at the end of massive star evolution, produce heavy elements, including those in the iron peak. Although the explosion mechanism is not yet fully understood, theoretical models can reproduce optical observations and observed elemental abundances. However, many nuclear reaction rates involved in explosive nucleosynthesis have large uncertainties, impacting the reliability of abundance predictions. To address this, we have previously developed a Monte Carlo-based nucleosynthesis code that accounts for reaction rate uncertainties and has been applied to nucleosynthesis processes beyond iron. Our framework is also well suited for studying explosive nucleosynthesis in supernovae. In this paper, we investigate 1D explosion models using the "PUSH method", focusing on progenitors with varying metallicities and initial masses around $M_\mathrm{ZAMS} = 16 M_{\odot}$. Detailed post-process nucleosynthesis calculations and Monte Carlo analyses are used to explore the effects of reaction rate uncertainties and to identify key reaction rates in explosive nucleosynthesis. We find that many reactions have little impact on the production of iron-group nuclei, as these elements are primarily synthesized in the nuclear statistical equilibrium. However, we identify a few "key reactions" that significantly influence the production of radioactive nuclei, which may affect astrophysical observables. In particular, for the production of ${}^{44}$Ti, we confirm that several traditionally studied nuclear reactions have a strong impact. However, determining a single reaction rate is insufficient to draw a definitive conclusion.

Effective field theories (EFTs) provide a powerful framework to parametrise unknown aspects of possible ultraviolet (UV) physics. For scalar fields in de Sitter space, however, new emergent phenomena can arise when the cut-off scale of the theory lies below the horizon scale $H$, as seen in the stochastic formalism of inflation. In this work, we study EFTs that, at leading order, reproduce the standard quartic theory in de Sitter, but with a variable cut-off identified with the mass of an integrated-out hidden sector. We perform the complete analytic computation for the tree- and loop-level matching between the effective $\lambda\phi^4$ theory and two possible UV realisations. We find that when the cut-off is much larger than the horizon, the theory admits a unitary description, up to exponentially suppressed corrections. In contrast, when the cut-off is lowered below $H$, the system evolves into a mixed state and diffusive effects emerge. Nevertheless, at leading order, the EFT remains local and reproduces the same effective quartic coefficient as in the unitary regime. Furthermore, for the EFT matching at the loop-level, the effective quartic coupling changes sign and becomes negative as the cut-off decreases, in agreement with the result obtained from the stochastic formalism. In general, for cosmological EFTs, our findings highlight the role of non-unitary effects and illustrate their regimes of validity, within and beyond perturbation theory.

We introduce a Rydberg-based single photon detector (SPD) for probing dark matter in the 0.1-10 meV mass range (20 GHz-2 THz). The Rydberg SPD absorbs photons produced and focused by the BREAD dish antenna and trades them for free, detectable electrons. At the lower end of the mass range, photons drive Rydberg-Rydberg transitions, which are read out via state-selective ionization. At higher masses, they directly ionize the Rydberg atoms.

Motivated by cosmological observations, we push the cosmological bootstrap program beyond the de Sitter invariance lamppost by considering correlators that explicitly break scale invariance, thereby exhibiting primordial features. For exchange processes involving heavy fields with time-dependent masses and sound speeds, we demonstrate that locality in the bulk implies a set of integro-differential equations for correlators on the boundary. These scale-breaking boundary equations come with a built-in memory kernel in momentum-kinematic space encapsulating the universe's evolution during inflation. Specialising to heavy fields with sinusoidal masses such as those found in axion monodromy scenarios, we show that a powerful synthesis of microcausality and analyticity allows an analytical solution of these equations at leading order in the amplitude of mass oscillations. Meanwhile, we also unveil non-perturbative information in the integro-differential equations by resumming apparent infrared divergences as parametric resonances. In addition, we provide a first-of-its-kind example of numerical bootstrap that directly maps out the solution space of such boundary equations. Finally, we compute the bispectrum and uncover, in the squeezed limit, a scale-breaking cosmological collider signal, whose amplitude can be exponentially enhanced (with respect to the Boltzmann suppression) due to particle production triggered by high-frequency mass oscillations.

We provide a fresh look at the cosmological constraints on axion-like particles (ALPs) that couple predominantly to photons, focusing on lifetimes $\tau_{a} \lesssim 10^{4}\, {\rm s}$ and masses $m_a\lesssim 10\,{\rm GeV}$. We consider Big Bang Nucleosynthesis (BBN) and Cosmic Microwave Background (CMB) bounds and explore how these limits depend upon the unknown reheating temperature of the Universe, $T_{\rm reh}$. Compared with some previous studies, we account for the rare decays of these ALPs into light hadrons and show that this leads to extended constraints for several reheating temperatures. Our limits are cast in a model-independent way, and we identify regions of parameter space where these ALPs could alleviate small tensions in the determinations of $N_{\rm eff}$ and the deuterium abundance.

At linear order we study perturbations to a Gödel background spacetime which includes expansion in addition to rotation. We investigate the transformation behaviour of these perturbations under gauge transformations and construct gauge invariant quantities. Using the perturbed energy conservation equation we find that there are conserved quantities in Expanding Gödel (EG) Cosmology, in particular a spatial metric trace perturbation, {\zeta} SMTP , which is conserved on large scales for pressureless dust. We intend to extend our discussion to a perfect fluid matter content with a view to also obtaining conserved quantities in this context.

Scattering black holes spin up and gain mass through the re-absorption of orbital angular momentum and energy radiated in gravitational waves during their encounter. In this work, we perform a series of numerical relativity simulations to investigate the spin-up and mass-gain for equal-mass black holes with a wide range of equal initial spins, $\chi_{\rm i}\in[-0.7,0.7]$, aligned (or anti-aligned) to the orbital angular momentum. We also consider a variety of initial momenta. Furthermore, we explore a range of incident angles and identify the threshold between scattering and merging configurations. The spin-up and mass-gain are typically largest in systems with incident angles close to the threshold value, large momenta, and negative (i.e. anti-aligned) initial spins. When evaluated at the threshold angle, we find that the spin-up decreases linearly with initial spin. Intriguingly, systems with initial spin $\chi_{\rm i}=0.7$ sometimes experience a spin-down, in spite of an increase in the black-hole angular momentum, due to a corresponding gain in the black-hole mass. Across the simulation suite, we find a maximum spin-up of $0.3$ and a maximum increase in the black-hole mass of $15\%$.

A new thermal view of scalar-tensor gravity, in which general relativity is the zero-temperature state of gravity, is applied to the specific subclass of $f(R)$ gravity theories and, specifically, to spatially homogeneous and isotropic universes. Within the limits of application of the new thermal formalism, results on the convergence to Einstein cosmology (or lack thereof) are first obtained for general $f(R)$ theories, and then illustrated with power-law and Starobinsky $f(R)$ gravity.

We report a laboratory search for axion-like particles (ALPs) in the eV-mass range using a variable-angle three-beam stimulated resonant photon collider. The scheme independently focuses and collides three laser beams, providing a cosmology- and astrophysics-independent test. By varying the angles of incidence, the center-of-mass energy can be scanned continuously across the eV range. In this work, we operated the collider in a vacuum chamber at a large-angle configuration, verified the spacetime overlap of the three short pulses, and performed a first search centered at $m_a\simeq 2.27~\mathrm{eV}$. No excess was observed. We thus set a $95\%$ C.L.\ upper limit on the pseudoscalar two-photon coupling, with a minimum sensitivity of $g/M\simeq 4.0\times 10^{-10}~\mathrm{GeV}^{-1}$ at $m_a=2.27~\mathrm{eV}$. This provides the first model-independent upper limit on the coupling that reaches the KSVZ benchmark in the eV regime and demonstrates the feasibility of eV-scale mass scans in the near future.

The current work investigates the structural properties of neutron stars in the presence of a strong magnetic field within the framework of f(R,T) modified gravity, where the matter-geometry coupling leads to deviations from general relativity at high matter densities. We present here the mass-radius sequences, as well as the mass and pressure distributions for various values of the modified gravity parameter and the central magnetic field. The modified Tolman-Oppenheimer- Volkoff equations are numerically solved using isotropic equations of state, specifically the APR, FPS, and SLy models. Comparing the corresponding results in the context of general relativity suggests that more negative values of the modified gravity parameter result in higher maximum gravitational masses. In contrast, strong central magnetic fields of up to 1018 Gauss cause only a slight decrease in maximum mass without disrupting spherical symmetry. Our findings are in agreement with the observed data from GW170817, PSR and NICER.

We introduce DenoiseGapFiller (DGF), a deep-learning framework specifically designed to reconstruct gravitational-wave ringdown signals corrupted by data gaps and instrumental noise. DGF employs a dual-branch encoder-decoder architecture, which is fused via mixing layers and Transformer-style blocks. Trained end-to-end on synthetic ringdown waveforms with gaps up to 20% of the segment length, DGF can achieve a mean waveform mismatch of 0.002. The residual amplitudes of the Time-domain shrink by roughly an order of magnitude and the power spectral density in the 0.01-1 Hz band is suppressed by 1-2 orders of magnitude, restoring the peak of quasi-normal mode(QNM) in the time-frequency representation around 0.01-0.1 Hz. The ability of the model to faithfully reconstruct the original signals, which implies milder penalties in the detection evidence and tighter credible regions for parameter estimation, lay a foundation for the following scientific work.

The detection of a subsolar object in a compact binary merger is regarded as one of the most compelling signatures of a population of primordial black holes (PBHs). We critically examine whether such systems can be distinguished from stellar binaries, such as those composed of neutron stars (NSs), which could also populate the subsolar mass range. Unlike PBHs, the gravitational-wave signal from stellar binaries is affected by tidal effects, which increase by several orders of magnitude as the mass decreases. We forecast the capability of current and future gravitational-wave (GW) detectors to constrain tidal effects in putative subsolar binaries. We also discuss the broader implications that the detection of a subsolar merger would have for both cosmology and nuclear physics.

By combining the (u,d) I-spin doublets or (d,s) U-spin doublets, the SU(3) flavor symmetry of light quarks can be decomposed into SU(2)$_I\times$U(1)$_Y$ or SU(2)$_U\times$U(1)$_Q$ subgroups, which have been widely adopted to categorize hadrons and their decay properties. The I-spin counterpart for the interactions among nucleons has been extensively investigated, i.e., the nuclear symmetry energy $E_\mathrm{sym}(n_\mathrm{b})$, which characterizes the variation of binding energy as the neutron to proton ratio in a nuclear system. In this work, we propose U-spin symmetry energy $E_\mathrm{U}(n_\mathrm{b})$ for hyperonic matter to characterize the variation of the binding energy with the inclusion of hyperons. In particular, being the lightest hyperon, $\Lambda$ hyperons are included in dense matter, where the U-spin symmetry energy $E_\mathrm{U}(n_\mathrm{b})$ is fixed according to state-of-the-art constraints from nuclear physics and astrophysical observations using Bayesian inference approach. It is found that $E_\mathrm{U}(n_\mathrm{b})$ is much smaller than that of $E_\mathrm{sym}(n_\mathrm{b})$, indicating much stronger proton-neutron attraction than that of nucleon-hyperon pairs. Consequently, $\Lambda$ hyperon potential increases significantly and becomes repulsive at large density, where there is more than 80\% probability that $\Lambda$ hyperons do not emerge in neutron stars. For those undergoing emergence within neutron stars, the onset density of $\Lambda$ hyperons $n_\mathrm{b}^\Lambda$ is typically larger than $\sim$0.8 fm$^{-3}$, corresponding to neutron stars more massive than 1.7 $M_\odot$.

We revisit the dynamics of a black hole accreting energy from a surrounding homogeneous and infinite space. We argue for a simple heuristic modification of the Schwarzschild approximation when the density of the medium is not negligible anymore. The resulting behavior is drastically modified: the mass divergence at finite time is cured and the thermodynamical properties are deeply changed. Some potential consequences for quantum gravity and bouncing models are also pointed out. Those conclusions being mostly obtained from a Newtonian approach, they only aim at guiding toward a more rigorous treatment. Still, interestingly, the behavior is far more convincing that the one usually obtained.

Forthcoming space-based gravitational-wave (GW) detectors will employ second-generation time-delay interferometry (TDI) to suppress laser frequency noise and achieve the sensitivity required for GW detection. We introduce an inverse light-path operator $\mathcal{P}_{i_{1}i_{2}i_{3}\ldots i_{n-1}i_{n}}$, which enables simple representation of second-generation TDI combinations and a concise description of light propagation. Analytical expressions and high-accuracy approximate formulas are derived for the sky- and polarization-averaged response functions, noise power spectral densities (PSDs), and sensitivity curves of TDI Michelson, ($\alpha,\beta,\gamma$), Monitor, Beacon, Relay, and Sagnac combinations, as well as their orthogonal $A, E, T$ channels. Our results show that: (i) second-generation TDIs have the same sensitivities as their first-generation counterparts; (ii) the $A, E, T$ sensitivities and the optimal sensitivity are independent of the TDI generation and specific combination; (iii) the $A$ and $E$ channels have equal averaged responses, noise PSDs, and sensitivities, while the $T$ channel has much weaker response and sensitivity at low frequencies ($2\pi fL/c\lesssim3$); (iv) except for the $(\alpha,\beta,\gamma)$ and $\zeta$ combinations and the $T$ channel, all sensitivity curves exhibit a flat section in the range $f_{n}<f\lesssim 1.5/(2\pi L/c)$, where the noise-balance frequency $f_{n}$ separates the proof-mass- and optical-path-dominated regimes, while the response-transition frequency $\sim 1.5/(2\pi L/c)$ separates the response function's low- and high-frequency behaviors; (v) the averaged response, noise PSD, and sensitivity of $\zeta$ scales with those of the $T$ channel. These analytical and approximate formulations provide useful benchmarks for instrument optimization and data-analysis studies for future space-based GW detectors.

In this paper, we present a new algorithm, MiniFool, that implements physics-inspired adversarial attacks for testing neural network-based classification tasks in particle and astroparticle physics. While we initially developed the algorithm for the search for astrophysical tau neutrinos with the IceCube Neutrino Observatory, we apply it to further data from other science domains, thus demonstrating its general applicability. Here, we apply the algorithm to the well-known MNIST data set and furthermore, to Open Data data from the CMS experiment at the Large Hadron Collider. The algorithm is based on minimizing a cost function that combines a $\chi^2$ based test-statistic with the deviation from the desired target score. The test statistic quantifies the probability of the perturbations applied to the data based on the experimental uncertainties. For our studied use cases, we find that the likelihood of a flipped classification differs for both the initially correctly and incorrectly classified events. When testing changes of the classifications as a function of an attack parameter that scales the experimental uncertainties, the robustness of the network decision can be quantified. Furthermore, this allows testing the robustness of the classification of unlabeled experimental data.

We investigate the equation of state (EOS) of hyperonic neutron star (NS) matter within a density-dependent relativistic mean-field (DDRMF) framework. The effects of scalar, vector, and mixed density dependencies in meson-baryon couplings are systematically examined along with alternative forms of the $\rho$-meson coupling. Several meson-nucleon parameter sets are explored here for the first time for neutron stars and compared with the standard DD2 EOS. Most new parameterizations produce stiffer EOSs, leading to neutron stars with larger radii and higher tidal deformabilities. However, the inclusion of $\Lambda$ hyperons softens these EOSs, and the resulting maximum masses still satisfy the two solar mass limits and agree with NICER measurements. These results highlight the importance of exploring alternative density dependencies in constraining dense matter through multi-messenger observations.

We investigate the spontaneous scalarization of generic, static, and spherically symmetric regular black holes supported by nonlinear electrodynamics. Starting from an arbitrary seed metric, we employ the P-dual formalism to reconstruct the electromagnetic sector and subsequently couple a real scalar field nonminimally. As a worked example, we apply the framework to the regular Balart-Vagenas black hole, showing that scalarized and scalar-free branches can coexist in a region where the scalarized configurations are entropically preferred. We further assess possible observational imprints, finding percent-level deviations in both the shadow size and the fundamental scalar quasi-normal modes ($< 10\%$ for small charge-to-mass ratios), indicating that current electromagnetic and gravitational-wave observations do not rule out these solutions. Our construction thus provides a general route to explore scalarization on top of nonlinear-electrodynamics-supported spacetimes, extending beyond specific Reissner-Nordström-like cases.

The detection of primordial gravitational waves would offer a direct evidence of inflation and valuable insights into the dynamics of the early universe. During post-inflation reheating period, when the inflaton coherently oscillates at the bottom of its potential, primordial stochastic gravitational waves may be sourced by its perturbative decay into particles of different spins. Assuming the behavior of the potential near the minimum as a polynomial $V(\phi)\sim \phi^k$, where $k\ge 2$, and treating the inflaton as coherently oscillating classical field, we calculate the decay of inflaton into a pair of spin $3/2$ particles accompanied by graviton emission. We numerically study the reheating dynamics and calculate the stochastic gravitational wave spectra. Our analysis shows that the gravitational wave spectra can offer insights into the microscopic physics during inflation.

We reassess prospects for direct detection of solar chameleons, in light of recent progress in modeling their production, and the availability of new XENONnT data. We show that the contribution from Primakoff production in the electric fields of electrons and ions dominates the electron recoil event rate, which is enhanced compared to earlier estimates based on magnetic conversion in the tachocline alone. We argue that the signal is governed by the effective coupling $\beta_{\text{eff}} \equiv \beta_{\gamma}M_e^{-4}$, which encodes the combined effects of production and detection, where $\beta_{\gamma}$ and $M_e$ are the chameleon-photon (conformal) coupling and chameleon-electron disformal coupling scale, respectively. Setting the height of the chameleon potential to the dark energy (DE) scale $\Lambda \simeq 2.4\,{\text{meV}}$, we show that XENONnT electron recoil data set the upper limit $\log_{10}\beta_{\text{eff}}<-6.9$. This limit is independent of the conformal matter coupling $\beta_m$ and index $n$, and applies to the whole class of inverse power-law chameleons, well beyond the $n=1$ case usually studied. We comment on how future multi-target experiments and lower-threshold analyses could distinguish solar chameleons from other light (pseudo)scalar particles such as axions. Our work demonstrates that existing dark matter direct detection experiments can probe regions of parameter space relevant to screened DE models, providing complementary tests to astrophysical and fifth-force searches at no additional experimental cost.

Effective field theories featuring light scalar fields play a pivotal role in addressing fundamental questions in (astro)particle physics and cosmology. However, such theories often confront hierarchy problems in the absence of a symmetry. Self-completion via classicalization offers a non-Wilsonian approach to ultraviolet (UV) completion, wherein new scalar self-interactions involving derivatives give rise to Vainshtein-like screening around energy-momentum sources. Rather than introducing new UV degrees of freedom to restore unitarity at high energies, these theories reshuffle their infrared (IR) degrees of freedom by generating extended semi-classical objects -- referred to as classicalons -- which decay into a multitude of soft particles. This mechanism incorporates non-localizable fields, thereby realizing a form of UV/IR mixing that is analogous to the dynamics of black holes in gravitational theories. In this article, having reviewed the fundamental principles of classicalization with a simple k-essence model, we then argue the necessity of maintaining a little hierarchy between the scalar mass and the scale of the first new resonances, thereby illustrating the impact of UV/IR mixing on hierarchy problems. Additionally, we investigate the effects of a scalar potential and couplings to fermions on the Vainshtein screening mechanism. We discuss that a chameleon-like screening mechanism must accompany the Vainshtein screening to preserve the integrity of classicalon solutions.