Papers for Wednesday, Jul 16 2025

This note complements the article on X-ray and infrared variability of the X-ray binary Cyg X-3 (WR+c), published by me and my co-authors (ApJ, v.926, p. 123, 2022). In that paper, a compact IR source was discovered in the system, located in the vicinity of the X-ray source associated with the relativistic companion. In the current note I refine the possible location of the IR source based on simple qualitative considerations.

We investigate the dynamical behavior of strange quark matter (SQM) objects, such as stars and planets, when subjected to radial oscillations induced by tidal interactions in stellar systems. Our study demonstrates that SQM objects can efficiently convert mechanical energy into hadronic energy due to the critical mass density at their surfaces of 4.7*10^{14} g/cm^3, below which SQM becomes unstable and decays into photons, hadrons, and leptons. We show that even small-amplitude radial oscillations, with a radius change of as little as 0.1%, can result in significant excitation energies near the surface of SQM stars. This excitation energy is rapidly converted into electromagnetic energy over short timescales approximately 1 ms, potentially leading to observable astrophysical phenomena. Higher amplitude oscillations may cause fragmentation or dissolution of SQM stars, which has important implications for the evolution of binary systems containing SQM objects and the emission of gravitational waves.

We present 1,800 multiwavelength Type Ib/c supernovae light curve models obtained by running the radiation transport code Sedona and varying the mass distribution, velocity profile, and abundance ejecta profiles of helium star progenitors. To create a flexible but physically-informed grid, we use autoencoders to construct a representation of ejecta profiles derived from stellar evolution models. We present simulated nearest-neighbor multiband light curves matches to SN 1994I, SN 2007gr, and iPTF13bvn to demonstrate that realistic light curves can be generated in our grid. We show that the ejecta velocity distribution, in particular, strongly influences the light curve, while variation in Ni-56 alone has a limited impact on the bolometric light curve, even in extreme and unphysical mixing schemes; however, mixing can modestly impact color evolution. Finally, we show that the Ni-56 mass, ejecta mass, and both the magnitude and structure of ejecta velocity distribution can be inferred from the multiband light curves, enabling improved inference over widely used semianalytical models.

We present updated empirical background images for JWST/NIRISS Wide-Field Slitless Spectroscopy (WFSS) for both orthogonal grisms (GR150C, GR150R) crossed with all NIRISS WFSS wide-band filters (F090W, F115W, F150W, F200W). The background images are created using carefully vetted science and calibration exposures and improve the quality of previous background reference files. We present our methodology to create the background images and assess their quality using background subtracted science data. Overall, background residuals reach below 1% of the sky brightness for all filter and grism combinations, corresponding to a decrease in the background RMS of a factor of up to 7 from previous background reference files. The new background images are available on the Calibration Reference Data System (CRDS) as of context 1365 and we recommend using them for improved quality of NIRISS WFSS data.

Merger trees track the hierarchical assembly of dark matter halos across cosmic time and serve as essential inputs for semi-analytic models of galaxy formation. However, conventional methods for constructing merger trees rely on ad-hoc assumptions and are unable to incorporate environmental information. Nguyen et al. (2024) introduced FLORAH, a generative model based on recurrent neural networks and normalizing flows, for modeling main progenitor branches of merger trees. In this work, we extend this model, now referred to as FLORAH-Tree, to generate complete merger trees by representing them as graph structures that capture the full branching hierarchy. We trained FLORAH-Tree on merger trees extracted from the Very Small MultiDark Planck cosmological N-body simulation. To validate our approach, we compared the generated merger trees with both the original simulation data and with semi-analytic trees produced using the Extended Press-Schechter (EPS) formalism. We show that FLORAH-Tree accurately reproduces key merger rate statistics across a wide range of mass and redshift, outperforming the conventional EPS-based approach. We demonstrate its utility by applying the Santa Cruz semi-analytic model (SAM) to generated trees and showing that the resulting galaxy-halo scaling relations, such as the stellar-to-halo-mass relation and supermassive black hole mass-halo mass relation, closely match those from applying the SAM to trees extracted directly from the simulation. FLORAH-Tree provides a computationally efficient method for generating merger trees that maintain the statistical fidelity of N-body simulations.

We investigate the dynamical stability of the S-type planet in the compact binary HD 41004. Using $N$-body simulations, we find that the planet could be dynamically stable at a mutual angle inclination up to $\sim75^\circ$. The von Zeipel-Lidov-Kozai (vZLK) mechanism becomes active when the mutual inclination is greater than 39.2$^\circ$. High-inclination orbits exhibit coupled oscillations in eccentricity and inclination, along with apsidal precession. Synthetic radial velocity (RV) modeling shows that these secular variations produce measurable signatures across a broad range of timescales, from full vZLK cycles to observationally accessible decades. For instance, a high mutual inclination at 75$^\circ$ can induce RV drifts exceeding 5 m s$^{-1}$ per planetary orbit ($\sim 1.9 \,\text{m s}^{-1}\, \text{yr}^{-1}$) in circular binary configurations. The presence of eccentric vZLK further accelerates these drifts, enhancing the detectability. Long-term RV observations of this system offer a unique pathway to dynamically constrain the orbital inclination, and thus determine the true mass of HD 41004 Ab. The degeneracy of mass-inclination is well known when using RV measurements alone. Our results highlight that HD 41004Ab and potentially other S-type planets in compact binaries are promising targets for breaking such a degeneracy by studying the dynamics induced by the vZLK mechanism through long-term high-precision RV monitoring.

Mira variables in globular clusters can provide an accurate and precise absolute calibration of their period-luminosity relations (PLRs) to independently anchor the cosmic distance scale and determine the Hubble constant. We present homogeneous near-infrared ($JHK_s$) time-series photometric observations of a sample of 55 candidate long-period variables in 18 globular clusters covering a wide metallicity range ($-1.7 < \textrm{[Fe/H]} < -0.1$ dex). The Gaia proper motions, long-period variability information, and optical-infrared colors are used to identify 41 Oxygen-rich Miras as members of the globular clusters. Mean luminosities of Miras in the $JHK_s$ bands are independently calibrated using the recommended distances and mean parallaxes to their host clusters. Cluster Mira PLRs exhibit scatter comparable to the Large Magellanic Cloud (LMC) variables and do not show any dependence on iron-abundance for a wide range of metallicities. We establish the accuracy of cluster Miras as independent anchors by determining a distance modulus to the LMC, $18.45 \pm 0.04$ mag, in agreement with the 1.2\% precise geometric distance. Our $H$-band photometry is transformed to derive {\it Hubble Space Telescope} F160W PLR for cluster Miras providing a three-anchor baseline with the LMC and NGC 4258. We employ three-anchor solution to determine distances to two type Ia supernovae host galaxies, NGC 1559 ($31.39\pm0.05$ mag) and M101 ($29.07\pm0.04$ mag), and provide a $3.7\%$ measurement of the Hubble constant, $H_0 = 73.06\pm 2.67$ km~s$^{-1}$~Mpc$^{-1}$. Similar to Cepheids, our independent baseline solution results in a local $H_0$ determination that is systematically larger than its inference from the early universe probes, further supporting the ongoing Hubble tension.

We present a molecular gas dynamical supermassive black hole (SMBH) mass measurement in the nearby barred lenticular galaxy NGC 1574, using Atacama Large Millimeter/sub-millimeter Array observations of the $^{12}$CO(2-1) emission line with synthesised beam full-widths at half-maximum of $0.''078\times0.''070$ ($\approx7.5\times6.7$ pc$^2$). The observations are the first to spatially resolve the SMBH's sphere of influence (SoI), resulting in an unambiguous detection of the Keplerian velocity increase due to the SMBH towards the centre of the gas disc. We also detect a previously known large-scale kinematic twist of the CO velocity map, due to a position angle (PA) warp and possible mild non-circular motions, and we resolve a PA warp within the central $0.''2\times0.''2$ of the galaxy, larger than that inferred from previous intermediate-resolution data. By forward modelling the data cube, we infer a SMBH mass of $(6.2\pm1.2)\times10^7$ M$_\odot$ ($1\sigma$ confidence interval), slightly smaller than but statistically consistent with the SMBH mass derived from the previous intermediate-resolution data that did not resolve the SoI, and slightly outside the $1\sigma$ scatter of the SMBH mass -- stellar velocity dispersion relation. Our measurement thus emphasises the importance of observations that spatially resolve the SMBH SoI for accurate SMBH mass measurements and gas dynamical modelling.

Stellar astrophysics relies on diverse observational modalities-primarily photometric light curves and spectroscopic data-from which fundamental stellar properties are inferred. While machine learning (ML) has advanced analysis within individual modalities, the complementary information encoded across modalities remains largely underexploited. We present DESA (Dual Embedding model for Stellar Astrophysics), a novel multi-modal foundation model that integrates light curves and spectra to learn a unified, physically meaningful latent space for stars. DESA first trains separate modality-specific encoders using a hybrid supervised/self-supervised scheme, and then aligns them through DualFormer, a transformer-based cross-modal integration module tailored for astrophysical data. DualFormer combines cross- and self-attention, a novel dual-projection alignment loss, and a projection-space eigendecomposition that yields physically structured embeddings. We demonstrate that DESA significantly outperforms leading unimodal and self-supervised baselines across a range of tasks. In zero- and few-shot settings, DESA's learned representations recover stellar color-magnitude and Hertzsprung-Russell diagrams with high fidelity ($R^2 = 0.92$ for photometric regressions). In full fine-tuning, DESA achieves state-of-the-art accuracy for binary star detection (AUC = $0.99$, AP = $1.00$) and stellar age prediction (RMSE = $0.94$ Gyr). As a compelling case, DESA naturally separates synchronized binaries from young stars, two populations with nearly identical light curves, purely from their embedded positions in UMAP space, without requiring external kinematic or luminosity information. DESA thus offers a powerful new framework for multimodal, data-driven stellar population analysis, enabling both accurate prediction and novel discovery.

The infall of the LMC into the Milky Way (MW) has generated dynamical disequilibrium throughout the MW. The interaction has displaced the MW's centre of mass, manifesting as an apparent 'reflex motion' in velocities of outer halo stars. Often, expensive high fidelity MW--LMC simulations are required to model these effects, though the range of model parameter spaces can be large and complex. We investigate the ability of lower fidelity, rigid MW-LMC simulations to reliably infer the model parameters of higher fidelity N-body and hydrodynamical cosmological zoom-in MW--LMC simulations using a Simulation-Based Inference (SBI) approach. We produce and release a set of 128,000 MW--LMC rigid potentials, with stellar haloes evolved to present-day, each adopting a unique combination of model parameters including the MW mass, the LMC mass and the dynamical friction strength. For these simulation parameters, we use SBI to find their posterior distributions. We find that our SBI framework trained on rigid MW--LMC simulations is able to correctly infer the true simulation LMC mass within a $1\sigma$ confidence interval from both N-body and cosmological simulations when knowledge of the induced MW reflex motion is provided as data. This motivates future applications of the presented SBI framework to observational data, which will help constrain both MW and LMC properties, as well as the dynamics of the MW's reflex motion.

We build upon FEGA25 (Contini et al 2025), a previously introduced semi-analytic model for galaxy formation and evolution, focusing on its enhanced treatment of supernova and active galactic nucleus feedback mechanisms. In addition to the traditional AGN feedback modes, negative (suppressing cooling), and the new positive mode (triggering star formation), we introduce two implementations of a third mode: the ejection of hot gas beyond the virial radius, AGNeject1 and AGNeject2. This component addresses a longstanding issue in semi-analytic models and hydrodynamical simulations: the overestimation of hot gas fractions in low and intermediate mass halos. FEGA25 is calibrated via MCMC using a suite of cosmological N-body simulations YS50HR, YS200, and YS300, and a comprehensive set of observed stellar mass functions across a wide redshift range. We find that supernova feedback dominates gas ejection in halos with logM_{halo} < approximately 12, while AGN feedback becomes increasingly important at higher halo masses. The AGNeject2 model, which activates primarily at late times, redshift < 1, reproduces a characteristic cavity, a U shaped feature in the baryon fraction at redshift zero, similar to trends observed in simulations like SIMBA and IllustrisTNG. Conversely, AGNeject1 yields a smoother, redshift independent evolution. Both models preserve the stellar and cold gas components and successfully reproduce the stellar to halo mass relation up to redshift 3. Our results emphasize that a physically motivated AGN driven mechanism capable of selectively removing hot gas is essential to accurately model the baryon cycle, particularly in intermediate halo mass regimes.

We present a detailed analysis of the most luminous and obscured Active Galactic Nuclei (AGNs) detected in the ultra-hard X-ray band (14-195 keV) by Swift/BAT. Our sample comprises 21 X-ray luminous (log $L_X/{\rm erg\,s^{-1}}>44.6$, 2-10 keV) AGNs at $z<0.6$, optically classified as Seyfert 1.9-2. Using NuSTAR, XMM-Newton, Suzaku, and Chandra, we constrain AGN properties such as absorption column density $N_H$, photon index $\Gamma$, intrinsic $L_X$, covering factor, and iron K$\alpha$ equivalent width. For sources with black hole mass estimates (12/20), we find a weak correlation between $\Gamma$ and Eddington ratio ($\lambda_{Edd}$). Of these, six ($50\pm13\%$) lie in the $N_H$-$\lambda_{Edd}$ "forbidden region'' and exhibit a combined higher prevalence of $N_H$ variability and outflow signatures, suggesting a transitional phase where AGN feedback may be clearing the obscuring material. For the 13/21 sources with multi-epoch X-ray spectra, $82^{+6}_{-16}\%$ exhibit variability in either 2-10 keV flux ($73^{+9}_{-16}\%$) or line-of-sight $N_H$ ($33^{+15}_{-10}\%$). For the 20/21 sources with available near-UV/optical spectroscopy, we detect [NeV]$\lambda$3426 in 17 ($85^{+5}_{-11}\%$), confirming its reliability to probe AGN emission even in heavily obscured systems. When normalized to the same [OIII]$\lambda$5007 peak flux as $z = 2$-$9$ narrow-line AGNs identified with JWST, our sample exhibits significantly stronger [NeV]$\lambda$3426 emission, suggesting that high-redshift obscured AGNs may be intrinsically weaker in [NeV]$\lambda$3426 or that [NeV]$\lambda$3426 is more challenging to detect in those environments. The sources presented here serve as a benchmark for high-redshift analogs, showing the potential of [NeV]$\lambda$3426 to reveal obscured AGNs and the need for future missions to expand X-ray studies into the high-redshift Universe.

We model the wavelength dependence of structural parameters for a mass-limited sample ($M_\star>10^{10}M_\odot$) of $\sim27,000$ quiescent galaxies with $0.2 < z < 0.6$ using $grizy$ photometry from Subaru/Hyper Suprime-Cam and dense spectroscopy from the HectoMAP survey. Based on Sérsic profile fits in all five bands, we estimate the circularized half-light radius $R_{e,c}$ and Sérsic index $n$ in two rest-frames: UV (3500 Å) and red (7000 Å). Combined with $M_\star$, $z$, and D$_n4000$, $R_{e,c}$ and $n$ enable exploration of the evolution in the structural properties - stellar mass correlations for quiescent galaxies with different stellar population ages. At intermediate redshift, quiescent galaxies at all stellar masses show a systematic decline in $R_{e,c}$ and rise in $n$ with rest-frame wavelength. These structural variations are stronger for galaxies that recently joined the quiescent population (newcomers) than for the descendants of galaxies that are already quiescent at the survey limit, $z \sim 0.6$ (aging population). The combined evidence supports inside-out quenching as the dominant mechanism halting star formation during this epoch. The typical size of a $M_\star\sim10^{11}M_\odot$ quiescent galaxy increases by $\sim30\%$ between $z \sim 0.6$ and $z \sim 0.2$ in the red and remains constant in the UV; newcomers are $\sim20\%$ larger than the aging population. In the UV, quiescent galaxies maintain a constant $n\sim4$ for the aging population and $n\sim2$ for newcomers; in the red, both subpopulations have de Vaucouleurs profiles. Our findings link newcomers to their direct progenitors in the star-forming population. For the aging population, we suggest minor mergers with progressively redder satellites at lower redshifts as the primary driver of quiescent galaxy evolution. Forthcoming sensitive large-area imaging surveys will allow testing this prediction.

We use the narrow [Ne v] $\lambda$3427 emission line detected in the recently published JWST spectra of two galaxies, at z = 6.9 and 5.6, to study the key properties of the active galactic nuclei (AGN) and the supermassive black holes in their centers. Using a new empirical scaling linking the [Ne v] line emission with AGN accretion-driven (continuum) emission, derived from a highly complete low-redshift AGN sample, we show that the [Ne v] emission in the two z > 5 galaxies implies total (bolometric) AGN luminosities of order L_bol~(4-8)x10^45 erg/s. Assuming that the radiation emitted from these systems is Eddington limited, the (minimal) black hole masses are of order M_BH>10^7 M_sun. Combined with the published stellar masses of the galaxies, estimated from dedicated fitting of their spectral energy distributions, the implied BH-to-stellar mass ratios are of order M_BH/M_host~0.1-1. This is considerably higher than what is found in the local Universe, but is consistent with the general trend seen in some other z > 5 AGN. Given the intrinsic weakness of the [Ne v] line and the nature of the [Ne v]-to-L_bol scaling, any (rare) detection of the [Ne v] $\lambda$3427 line at z > 5 would translate to similarly high AGN luminosities and SMBH masses, thus providing a unique observational path for studying luminous AGN well into the epoch of reionization, including obscured sources.

Recent observations have unveiled a population of pulsars with spin periods of a few minutes to hours that lie beyond the traditional ``death line.'' If they originate from neutron stars (NSs), the existence of such ultra-long period pulsars (ULPs) challenges our current understanding of NS evolution and emission. In this work, we propose a new channel for disk formation based on NSs born in close binaries with main-sequence companion stars. Using a hydrodynamic simulation of supernova-companion interactions, we show that a newborn NS may gravitationally capture gas as it moves through the complex density field shaped by the explosion. For a binary separation of $20\rm~R_\odot$ and a companion mass of $4\rm~M_\odot$, we find the occurrence fraction for disk formation around unbound NSs to be $\sim10\%$. By modeling the disk evolution and its interaction with the NS, we find a bimodal distribution in spin periods: canonical pulsars with $P\lesssim10\rm\,s$ are the ones who lack disks or whose magnetospheres never interacted with the disk, and ULPs with $10^3\lesssim P<10^5\rm\,s$ are produced when the system undergoes a short-lived ``propeller'' phase during which the NS undergoes rapid spin-down. Such ULPs are formed under strong initial dipolar magnetic field strengths $B_0\gtrsim10^{14}\rm\,G$, with a formation rate of $10^{-4}\rm\,yr^{-1}$ in the Milky Way. We also find that a small population of pulsars with moderate magnetic field strengths ($10^{13}\lesssim~B_0\lesssim10^{14}\rm\,G$) and relatively slow initial periods ($P_0\gtrsim0.1\rm\,s$) evolve to $P\sim10^2\rm\,s$, filling the gap between the bimodal distribution. Thus, our model provides a unified explanation for pulsars beyond the ``death line.''

Far-infrared (FIR) and mid-infrared (MIR) fine-structure lines (FSLs) are widely used for studying galaxies nearby and faraway. However, interpreting these lines is complicated by factors including sample and data bias, mismatch between resolved calibrations and unresolved observations, limitations in generalizing from case studies, and unresolved issues like the origin of [C II] emission and the so-called ``deficit.''In this series of papers, we assemble and analyze the most comprehensive atlas of FSL data to date. We explore their empirical correlations (paper I), compare them with photoionization models that cover multiphase gas (paper II), and discuss their physical origins and the new perspectives they offer for studying physical properties (paper III). The first paper introduces value-added catalogs of global FSL data of low- and high-z galaxies compiled from the literature, covering most of the existing observations, supplemented with ancillary ultraviolet to FIR information. Our analysis focus on commonly used diagnostics, such as electron density, radiation field strength, metallicity, and electron temperature. We present their distributions across different galaxy samples and redshifts, and cross-validate the reliability of these diagnostics in measuring physical conditions. By examining empirical relations, we identify the contribution of active galactic nuclei (AGN) to the FIR FSLs [O III]88 and [O I]63, and reveal a bias in density measurements. FIR FSLs show good concordance with their optical counterparts. Our findings indicate that variations in FSL ratios are primarily driven by the relative abundances of emitting ions, underscoring their value as tracers of metallicity and radiation field strength. Finally, we compare the FIR FSL properties of low- and high-z galaxies, discussing both their similarities and differences.

Context. The Dust Settling Instabilty (DSI) is a member of the Resonant Drag Instabilities (RDI) family, and is thus related to the Streaming Instability (SI). Linear calculations found that the unstratified monodisperse DSI has growth rates much higher than the SI even with lower initial dust to gas ratios. However, recent nonlinear investigation found no evidence of strong dust clumping at the saturation level. Aims. To investigate the nonlinear saturation of the mono- and polydisperse DSI. We examine the convergence behaviour wrt. both the numerical resolution and the number of species. By characterising the morphology of the dust evolution triggered by the DSI, we can shed more light on its role in planetesimal formation. Methods. We perform a suite of 2D shearing box hydro simulations with the code Idefix, both in the mono- and polydisperse regimes. We focus on the time evolution of the maximum dust density, noting the time at which the instability is triggered, as well as analyse the morphology of the resultant structure. Results. In our monodisperse simulations, the maximum dust density increases and the instability saturates earlier with higher spatial resolution, with no signs of convergence. The polydisperse simulations do seem to converge with the number of species and produce maximum dust densities that are comparable to, albeit lower than, the monodisperse simulations. Different dust species tend to form adjacent but separate dust filaments, which may have implications on dust growth and further clumping. Conclusions. The monodisperse DSI produces dust structure at densities high enough that likely leads to clumping. The polydisperse DSI produces lower but comparable dust densities. Our idealised treatment suggests that the DSI is important for planetesimal formation, as it suffers less than the SI from including a dust size distribution.

Detection of extensive air showers with radio antennas is an appealing technique in cosmic ray physics. However, because of the high level of measurement noise, current reconstruction methods still leave room for improvement. Furthermore, reconstruction efforts typically focus only on a single aspect of the signal, such as the energy fluence or arrival time. Bayesian inference is then a natural choice for a holistic approach to reconstruction, yet, this problem would be ill-posed, since the electric field is a continuous quantity. Information Field Theory provides the solution for this by providing a statistical framework to deal with discretised fields in the continuum limit. We are currently developing models for this novel approach to reconstructing extensive air showers. The model described here is based on the best current understanding of the emission mechanisms: It uses parametrisations of the lateral signal strength distribution, charge-excess contribution and spectral shape. Shower-to-shower fluctuations and narrowband RFI are modelled using Gaussian processes. Combined with a detailed detector description, this model can infer not only the electric field, but also the shower geometry, electromagnetic energy and position of shower maximum. Another big achievement of this approach is its ability to naturally provide uncertainties for the reconstruction, which has been shown to be difficult in more traditional methods. With such an open framework and robust computational methods based in Information Field Theory, it will also be easy to incorporate new insights and additional data, such as timing distributions or particle detector data, in the future. This approach has a high potential to exploit the full information content of a complex detector with rigorous statistical methods, in a way that directly includes domain knowledge.

Scaling relations with the bag constant parameter are investigated for Strange Quark Matter (SQM) stars in the presence of gravitationally strong magnetic fields minimally coupled with matter, considering both massless and massive strange quark scenarios. Assuming a simple model for such coupling under the approximation of spherical symmetry, a phenomenological scaling formula for the maximum mass of stars is derived as a function of the surface magnetic field and the strange quark mass. This formula is applicable for all formally admissible values of the free parameters, and strict scaling with the bag constant is retained only for a vanishing strange quark mass. As a byproduct of this study, the mathematical structure of the equation of state for the relativistic SQM model with a massive strange quark is revisited without approximations. It is observed that the contribution of the electron term to the energy density cannot be neglected in the theoretical limit of large strange quark masses. Consequently, the maximum mass of SQM stars increases with sufficiently large strange quark mass, contrasting with the behavior observed for low strange quark masses.

Being one of the most populated mean motion resonances (MMR) with Neptune and lying close to the inner boundary of the present day cold classical disk, observations of the orbital and surface class distributions of the plutinos in the 3:2 MMR provide constraints on Neptune's migration and insight into the compositional structure of the pre-migration planetesimal disk. Here, we present observations of the surface reflectance of 43 small to mid-size (H_V >~ 5) transneptunian objects (TNOs) through the grz wavelength range, 14 of which are plutinos. We classify the surfaces of these TNOs using the two-surface class model (FaintIR and BrightIR surface classes) proposed by Fraser and collaborators, where the FaintIR surface class is dominated by cold classicals. Incorporating similar observations of plutinos from the literature for a total sample size of 43 plutinos, we find that the osculating inclination distributions (i_osc) of the FaintIR and BrightIR plutinos are statistically distinguishable at 99.3% significance, where (6/7) of the plutinos with i_osc > 4.5° have FaintIR surfaces. This is most easily explained if the FaintIR and BrightIR planetesimals were radially partitioned in the primordial planetesimal disk before being captured into the 3:2 resonance. While this could be evidence that the primordial cold classical disk with FaintIR surfaces was broader in the past by ~3 au in the sunward direction, we cannot rule out the alternative explanation that these FaintIR plutinos were scattered from the ~42.5-48 au region from the Sun and captured into the 3:2 resonance.

The Pierre Auger Observatory has been operating in Malargue, Province of Mendoza, western Argentina, for over two decades, significantly advancing our understanding of cosmic rays. Beyond its scientific mission, the installation and operation of the Observatory has had profound social, economic, educational and cultural impact on the local community, the region and worldwide. More than 90 percent of the Observatory's annual operational budget is invested in the region, benefiting sectors such as tourism, hospitality, gastronomy, and local commerce. Additionally, the presence of international visitors and collaborations has fostered a rich cultural exchange. Malargue has emerged as a destination for scientific tourism, with the Observatory as a major attraction, having welcomed over 178,000 visitors since its inauguration and boosting the development of the region. This article explores the broad direct and indirect benefits of the Auger Observatory and the key lessons learned from this endeavor. A new International Agreement signed in 2024 ensures the continuity of the project for at least another decade, until 2035, reaffirming its scientific, economic, and social relevance.

Cosmic ray (CR) feedback has been proposed as a powerful mechanism for driving warm gas outflows in galaxies. We use cosmological magnetohydrodynamic simulations to investigate the impact of CR feedback on neutral hydrogen (HI) in a $10^{11}\,M_\odot$ dark matter halo at $2<z<4$. To this end, we post-process the simulations with ionizing radiative transfer and perform Monte Carlo Lyman-$\alpha$ (Lya) transfer calculations. CR feedback reduces HI column densities around young stars, thereby allowing more Lya photons to escape and consequently offering a better match to the Lya luminosities of observed Lya emitters. Although galaxies with CR-driven outflows have more extended HI in the circumgalactic medium, two Lya line properties sensitive to optical depth and gas kinematics - the location of the red peak in velocity space ($v_\mathrm{red}$) and relative strength of the blue-to-red peaks ($B/R$) - cannot distinguish between the CR-driven and non-CR simulations. This is because Lya photons propagate preferentially along low HI density channels created by the ionizing radiation, thereby limiting the scattering with volume-filling HI. In contrast, the observed low flux ratios between the valley and peak and the surface brightness profiles are better reproduced in the model with CR-driven outflows because the Lya photons interact more before escaping, rather than being destroyed by dust as is the case in the non-CR simulation. We discuss the potential cause of the paucity of sightlines in simulations that exhibit prominent red peaks and large $v_\mathrm{red}$, which may require the presence of more volume-filling HI.

We fit the cosmic-ray spectrum measured with the Pierre Auger Observatory's surface detectors above an energy of $10^{17}$ eV, along with composition information inferred from the depth of shower maximum measured with its fluorescence detectors above an energy threshold of $10^{17.8}$ eV. We consider astrophysical scenarios with two distinct extragalactic source populations: one dominating the flux above a few EeV, and the other dominating at lower energies, with representative nuclei being injected at the sources with power-law spectra and rigidity-dependent cutoffs. The high-energy population exhibits a hard source injection spectrum and a relatively heavy composition, while the low-energy population exhibits a softer spectrum and a lighter composition. Extending the fit down to the low energies considered here shows the potential to test the energy region towards the Galactic to extragalactic transition with the data of the Pierre Auger Observatory. In particular, the Galactic contribution is expected to be still sizable at the lowest energies considered, and the extragalactic contribution needs to become suppressed for decreasing energies, an effect that could naturally result from a magnetic-horizon-induced suppression.

The LHAASO observatory has recently measured details of the cosmic-ray (CR) spectrum in the knee region (1 -- 10 PeV) with unprecedented precision, including its average CR mass composition and the spectrum of the proton component. We use these precision measurements, combined with direct measurements of CRs by space-based detectors, to derive predictions for the spectrum of diffuse gamma-ray and neutrino emission from the interstellar medium under the assumption that the CR spectrum is universal throughout the Milky Way. We compare these predictions with the Fermi-LAT and LHAASO measurements of the diffuse gamma-ray flux from inner and outer Galactic Plane regions and with estimates of the neutrino flux based on the IceCube data for the same Galactic Plane regions. We notice that the model predictions exceed LHAASO gamma-ray measurements at energies above 100 TeV. This excess can be interpreted within a CR knee model assuming a "local PeV CR bubble''. Within this model, we infer the extension of the local PeV CR bubble of 1.5 +/- 0.3 kpc in the direction of the inner Galaxy and of 0.7+/-0.3 kpc toward the outer Galaxy.

Gamma-ray bursts (GRBs) are the most luminous astrophysical transients, known to be associated with core collapse of massive stars or mergers of two compact objects such as two neutron stars. They are followed by multi-wavelength afterglow emission originating from the deceleration of the relativistic jets by the ambient medium. The study of after emission offers crucial insights into the physics of relativistic shocks, the properties of the circumburst environment, as well as the physical and geometrical structure of relativistic jets, as well as the viewing geometry of the observer. We present VegasAfterglow, a newly developed, high-performance C++ framework designed for modeling GRB afterglows with flexibility and computational efficiency as keynotes of design. The framework self-consistently solves forward and reverse shock dynamics and calculates synchrotron (including self-absorption or all spectral regimes) and inverse Compton radiation (including Klein-Nishina corrections); it can handle arbitrary user-defined ambient density profiles, central engine activity histories, viewing angles, and the jet structures of energy, Lorentz factor, and magnetization profiles. It supports both relativistic and non-relativistic regimes and includes lateral jet spreading effects. In this paper, we describe the numerical implementation of the framework and assess its computational performance. Our results demonstrate that VegasAfterglow is well-suited for interpreting current and future multi-wavelength observations in the era of multi-messenger astronomy.

Recent studies suggest that the angular momentum evolution of late-M and brown dwarfs differs from the well-known spin-down evolution of hotter stars. Characterizing the distribution of rotation periods of these objects in the solar neighborhood can help elucidate this evolutionary pathway just above, at, and below the hydrogen burning limit. In this paper, we examine 399 candidate single late-M dwarfs with $G - G_{RP} \geq 1.4$ mag ($\gtrsim$M6) using TESS light curves. To determine rotation periods, we employed Lomb-Scargle Periodograms to provide a first estimate of the period, then refined them with a Gaussian Process approach, requiring multi-sector confirmation when available. We found 133 rotation periods, ranging from 2 hours to 6 days, and amplitudes between 0.08% and 2.71%. We find that the observed variability fraction in late-M dwarfs rises with the number of available TESS sectors, approaching an apparent ceiling of ~50%. This likely reflects a detection limit determined by viewing geometry and supports the idea that spot-induced variability is common across the late-M and brown dwarf population. In our comparison with previously published late-M dwarf rotation periods reported, we found consistent results, confirming or updating 31 periods. Our findings expand the number of previously known late-M dwarf periods under 1 day by 76%. Combined with published rotation periods for a broader range of spectral types, we find a lower envelope on the rotation period decreasing from 5 hours at early-M dwarfs to 1 hour at L, T, and Y dwarfs.

Under the standard model of hierarchical structure formation, the overall geometry of galaxy clusters is better described by a triaxial ellipse than a sphere. As a result, applying spherically-symmetric models can result in significant biases. These biases can be mitigated by fitting a triaxial model, requiring deep multiprobe data and a set of physically motivated models to describe them. Here we present a multiprobe triaxial analysis methodology based on the data available for galaxy clusters in the Cluster Heritage project with XMM-Newton - Mass Assembly and Thermodynamics at Endpoint of structure formation (CHEX-MATE), which includes X-ray data from XMM-Newton, SZ data from Planck and ACT, and WL data from Subaru. This work builds on our previous development of a gas-only X-ray and SZ triaxial fitting formalism in Paper I. We apply our approach to the CHEX-MATE cluster PSZ2 G313.33+61.13 (Abell 1689) and find that it is elongated along the line of sight relative to the plane of sky by a factor of $\mathcal{R}_{LP} = 1.27 \pm 0.02$. As a result, the WL mass obtained from our triaxial fit, $\text{M}_{200c}=(13.69_{-1.41}^{+1.56})\times10^{14} \text{M}_{\odot}$, is significantly lower than the value of $(17.77_{-1.75}^{+2.00})\times10^{14} \text{M}_{\odot}$ obtained from a spherically-symmetric fit that otherwise employs the same methodology. Our triaxial fit finds a concentration of $c_{200c}=8.55_{-1.61}^{+2.20}$, consistent with the spherically-symmetric value of $9.99_{-1.78}^{+2.26}$, which suggests that the unexpectedly high concentration in Abell 1689 is not due to triaxiality and orientation. We also measure the non-thermal pressure fraction at radii between 0.18-1.37 Mpc, finding a minimum of approximately 20 per cent at intermediate radii increasing to near 30 per cent at both the smallest and largest radii, and with a typical measurement precision of $\pm$5 per cent.

Observations and theoretical simulations suggest that the large scale environment plays a significant role in how galaxies form and evolve and, in particular, whether and when galaxies host an actively accreting supermassive black hole in their center (i.e., an Active Galactic Nucleus, or AGN). One signature of AGN activity is luminosity variability, which appears in the mid-infrared (mid-IR) when circumnuclear dust reprocesses UV and optical photons from the AGN accretion disk. We present here a suite of constraints on the fraction of AGN activity in the most underdense regions of the universe (cosmic voids) relative to the rest of the universe (cosmic walls) by using ~12 years of combined multi-epoch data from AllWISE and NEOWISE to quantify mid-IR variability. We find clear evidence for a larger mid-IR variability-AGN fraction among high and moderate-luminosity void galaxies compared to their wall counterparts. We also show that mid-IR variability identifies a rather large and unique population of AGNs, the majority of which have eluded detection using more traditional AGN-selection methods such as single-epoch mid-IR color selection. The fraction of these newly-recovered AGNs is larger among galaxies in voids, suggesting once again more prolific AGN activity in the most underdense large scale structures of the universe.

The study of integrating photonic devices into astronomical instruments is the primary focus of astrophotonics. The growth in this area of study is relatively recent. Research related to astronomical spectroscopic phenomena has received a lot of attention in recent times. There are several important advantages to integrating photonics technology into an astronomical instrument, such as cost savings because of increased reproducibility, thermal and mechanical stability, and miniaturization. This paper provides a brief review of recent advances in astrophotonics.

We couple a simplified model for the galactic chemical evolution, with software that models the condensation of dust in protoplanetary disks and software that models the interior structure of planets in order to estimate the effects that the galactic chemical evolution has on the properties of planets as they form over time. We find that the early abundance of elements formed from the evolution and death of high-mass stars (such as Oxygen, Silicon, and Magnesium) yields planets with larger mantles and smaller cores. The later addition of elements produced in low-mass stars (such as Iron and Nickel) causes the planet cores to become relatively larger. The result is planets that orbit older stars are less dense than planets orbiting younger stars. These results are broadly consistent with recent observations of planet properties from stars of varying ages.

The Ly$\alpha$ Tomography IMACS Survey (LATIS) has produced large 3D maps of the intergalactic medium (IGM), providing a new window on the cosmic web at $z\sim2.5$. A key advantage of Ly$\alpha$ tomography is that it enables the discovery of overdense regions without the need to detect their galaxy members in spectroscopic surveys, circumventing possible selection biases. We use these maps to identify 37 IGM-selected overdensities as regions of strong and spatially coherent Ly$\alpha$ absorption. Simulations indicate that 85% of these are protoclusters, defined as the progenitors of $z=0$ halos with mass $M_{\rm desc} > 10^{14} M_{\odot}$, and that nearly all of the rest are protogroups ($10^{13.5} < M_{\rm desc} / M_{\odot} < 10^{14}$). We estimate the masses and space densities of the IGM-selected overdensities and show they are in accordance with mock surveys. We investigate the LATIS counterparts of some previously reported protoclusters, including the proto-supercluster Hyperion. We identify a new component of Hyperion beyond its previously known extent. We show that the Ly$\alpha$ transmission of the galaxy density peaks within Hyperion is consistent with a simple physical model (the fluctuating Gunn-Peterson approximation), suggesting that active galactic nucleus feedback or other processes have not affected the large-scale gas ionization within this structure as whole. The LATIS catalog represents an order-of-magnitude increase in the number of IGM-selected protogroups and protoclusters and will enable new investigations of the connections between galaxies and their large-scale environments at cosmic noon.

We investigate the consistency of intergalactic medium (IGM) tomography and galaxy surveys as tracers of the cosmic web and protoclusters at $z \sim 2.5$. We use maps from the Ly$\alpha$ Tomography IMACS Survey (LATIS), which trace the distributions of Lyman-break galaxies (LBGs) and IGM Ly$\alpha$ absorption on $\simeq 4$ $h^{-1}$ cMpc scales within the same large volume. Overall, the joint distribution of IGM absorption and LBG density is well constrained and accurately described by a simple physical model. However, we identify several exceptional locations exhibiting strong IGM absorption indicative of a massive protocluster, yet no coincident overdensity of LBGs. As discussed by Newman et al., whose results we revise using the complete LATIS survey data, these are candidate ultraviolet (UV)-dim protoclusters that may harbor distinct galaxy populations missed by rest-UV spectroscopic surveys. We present follow-up observations targeting one such candidate embedded within Antu, an extended region of IGM absorption at $z=2.685$ that contains five IGM-selected protoclusters and has a total mass of $3 \times 10^{15}~M_{\odot}$. Ly$\alpha$ emitters trace the overall structure of Antu but avoid the center of the candidate UV-dim protocluster, which also appears to contain no submillimeter-selected sources. A near-infrared spectroscopic galaxy census is needed to determine whether this large region is dominated by galaxies with reduced or absent star-formation activity. This work adds to a growing and puzzling literature on discrepancies among different galaxy and IGM tracers, whose resolution promises to shed light on the early stages of environment-dependent galaxy evolution.

The origins of ultra-high-energy particles remain one of the most profound mysteries in astrophysics. If nearby transient sources of ultra-high-energy particles exist, we might expect correlated emission of neutrinos and photons, arriving in close temporal and spatial coincidence. The IceCube Neutrino Observatory, located at the South Pole, is sensitive to neutrinos from TeV to EeV energies, while the Pierre Auger Observatory, in Argentina, detects cosmic rays and has the capability of observing ultra-high-energy photons using surface and fluorescence detectors. The ultra-high-energy photon candidates reported by the Auger Collaboration, though consistent with cosmic ray backgrounds, provide a compelling opportunity to search for correlated neutrino-photon events. In this contribution, we present the framework to search for ultra-high-energy transients by combining multi-flavour neutrino data from IceCube with photon candidates from the Auger Detector from 2011 to 2017. We will report the sensitivities that we expect to achieve from the search and the astrophysical implications of the possible outcomes.

We explore the consequences of a novel but increasingly well-supported hypothesis that supermassive black holes may have formed from primordial black holes form ed prior to, and rapidly growing in, the radiation-dominated universe. We show that this hypothesis can predict the luminosity of quasars and their luminosity distribution. With reasonable values of the parameters introduced, these predictions are borne out by observations. The model predicts density evolution in accordance with observations. If the same galaxy interaction rate creates quasars and radio galaxies, whose primordial black hole nuclei seem somewhat less massive, their relative number densities reflect relative lifetimes in these states.

The physical mechanisms that regulate the collapse of high-mass parsec-scale clumps and allow them to form clusters of new stars represent a crucial aspect of star formation. To investigate these mechanisms, we developed the Rosetta Stone project: an end-to-end (simulations-observations) framework that is based on the systematic production of realistic synthetic observations of clump fragmentation and their comparison with real data. In this work, we compare ALMA 1.3mm continuum dust emission observations from the SQUALO survey with a new set of 24 radiative magnetohydrodynamical simulations of high-mass clump fragmentation, post-processed using the CASA software to mimic the observing strategy of SQUALO. The simulations were initialized combining typical values of clump mass (500,1000 solar masses) and radius (~0.4pc) with two levels of turbulence (Mach number of 7,10) and three levels of magnetization (mass-to-flux ratio of ~3,10,100). Following the clump evolution over time with two random seeds projected along three orthogonal directions, we produced a collection of 732 synthetic fields. The synthetic observations of clump fragmentation at ~7000AU revealed between 2 and 14 fragments per field. Among the initial conditions of the simulations, magnetic fields have the largest impact on the fragment multiplicity at these scales. In advanced stages of clump evolution, a lower number of fragments is preferentially associated with magnetized clumps. Fragments identified at ~7000AU correspond to individual or multiple sink particles in ~75% of the cases, suggesting that not all fragments are actively forming stars. Both sinks and fragments accrete mass throughout the whole clump evolution, favoring a scenario in which fragments are not isolated from the environment. Our study demonstrates the importance of synthetic observations in interpreting results from interferometric observations.

Identifying Lyman continuum (LyC) leakers at intermediate redshifts is crucial for understanding the properties of cosmic reionizers, as the opacity of the intergalactic medium (IGM) prevents direct detection of LyC emission from sources during the Epoch of Reionization (EoR). In this study, we confirm two new LyC candidate leakers at $z \sim 3$ in the Abell 2744 cluster field, with absolute escape fractions ($f_{\text{esc}}$) of $0.90^{+0.07}_{-0.86}$ and $0.60^{+0.37}_{-0.56}$, respectively. The LyC emission was detected using HST/WFC3/F275W and F336W imaging. These two candidate leakers appear faint ($ M_{\text{UV}} = -18.1 \pm 0.1 \text{ and } -17.81 \pm 0.11$), exhibit blue UV continuum slopes ($\beta = -2.42 \pm 0.05 \text{ and } -1.78 \pm 0.19$), have low masses ($M_\star \sim 10^{7.73} \pm 0.1 \text{ and } 10^{7.07} \pm 0.05 M_\odot$) and show \lya\ equivalent widths of $90 \pm 3$ Å and $28 \pm 12$ Å, respectively. The discovery of these two LyC candidate leakers was achieved in a catalog of 91 spectroscopically confirmed sources using JWST and/or MUSE public spectra. We also analyze properties that have been proposed as indirect indicators of LyC emission, like \lya, O32 ratio, and $M_\star$: we create subsample of galaxies selected according to such properties, stack the LyC observations of these subsample and assess the limits in escape fractions in the stacks. By analysing the individual candidates and the stacks, in the context of the currently limited sample of known LyC leakers at $z \sim 3$, we aim to enhance our understanding of LyC escape mechanisms and improve our predictions of the LyC $f_{\text{esc}}$ during the EoR.

In this paper we describe the absorption determination by the Q-method for 2MASS photometry ($J$, $H$ and $K_S$ bands). Using the Pleiades and Praesepe stars, we determine the zero-reddening sequence for different values of the color excess ratios $E(J-H)/E(H-K_S)$. In this paper we consider a sequence consisting of two segments, that leads to an uncertainty in the determining of absorption - one value of the Q parameter corresponds to two values of the non-reddened color index. We propose a method to select a segment of the zero-reddening sequence for the main sequence stars of the cluster. The method is based on the difference in the position of stars of different segments in the cluster luminosity function. To test the proposed method, we simulate the luminosity functions of clusters with the non-uniform absorption distribution in the cluster region. With the typical absorption values in embedded clusters, about 10 % of stars are erroneously assigned, but in some cases this fraction can reach 20 %. Thus, despite the fact that irregular absorption distorts the distribution of stars of different segments on the cluster luminosity function, our method allows to separate stars with an error of no more than 20 %.

Young, solar-like stars in the pre-main sequence (PMS) stage exhibit vigorous magnetic activity that significantly influences their circumstellar environments and the processes of planetary formation and evolution. In binary systems, tidal forces and magnetic interactions can further shape the magnetic geometry. We report a longitudinal preference of star spots, chromospheric activities, and flares in the active single-lined spectroscopic PMS binary system V2279 Cyg, based on long-term photometric observations from \textit{Kepler} and \textit{TESS} alongside spectroscopic data from LAMOST. The system is classified as a weak-line T Tauri binary, with component masses estimated at 0.86 $M_\odot$ and 0.27 $M_\odot$. V2279 Cyg's nearly circular orbit is synchronized with its 4.126-day rotational period. Observations reveal large star spot regions clustered near the far-side hemisphere. Spectroscopic data show strong, double-peak H$\alpha$ emission, the strength of which is highly correlated with star spot distribution, indicating the presence of an active longitude on the primary star. We also mapped the prominence structure co-rotating with the primary star, suggesting a dense structure close to the near-side hemisphere. Furthermore, we identify an inactive longitude of flares during the 4-year \textit{Kepler} observations, where the frequency of flare activity is significantly reduced after the superior conjunction, marking the first such identification in active binary systems. Additionally, a white light superflare, releasing energy of $2.5 \times 10^{37}$ erg, was detected in \textit{TESS} observations. These findings provide valuable insights into the magnetic field geometry and dynamo processes in PMS binaries, underscoring the critical role of tidal interactions in shaping magnetic activities.

Quasi-periodic eruptions (QPEs) are a class of X-ray repeating burst phenomena discovered in recent years. Many models have been proposed to study this phenomenon, there remains significant debate regarding the physical origin of QPEs. In our previous work, we developed a disk instability model with a large-scale magnetic field and successfully reproduced the light curves and spectral characteristics of several QPE sources. We further investigate the model in this work, aiming to explain two key observational features: the dispersion in eruption periods and the peak temperatures during eruptions. The model reveals critical thresholds ($\dot{M}_{\rm crit}$, $\beta_{1,\rm crit}$) that separate systems into stable regimes with minimal period variations and unstable regimes where periods are highly sensitive to accretion rate and magnetic field parameter, while peak temperatures remain nearly constant across the parameter space. This framework successfully explains both the regular eruptions observed in sources like GSN 069 and the stochastic behavior in sources like eRO-QPE1, and simultaneously accounting for the observed temperature stability during long-term QPEs evolution.

PG 1553+113 is a high-frequency peaked BL Lac object (HBL), with redshift 0.433, detected with the current generation of IACTs (Imaging Atmospheric Cherenkov Telescopes) up to $\sim$ 1 TeV. Interestingly, the continuous $\gamma$-ray lightcurve collected by Fermi-LAT since 2008 showed a signature of a periodic modulation of $2.18 \pm 0.08$ years at energies above 100 MeV and 1 GeV. In addition, the source shows clear variabiliy down to day-scale in all bands. XMM-Newton data recently showed rapid variability in the X-ray band down to $2.4 \pm 0.7$ ks. Short-timescale (sub-hour) variabilities are a key observable to constrain the size of the photon-emitting region inside the blazar jet. The LST-1 (first protoype of the Large-Sized Telescope) of the CTAO (Cherenkov Telescope Array Observatory) is located on Roque de los Muchachos in La Palma, Spain. With its high sensitivity at low energies (20-150 GeV), it provides a unique opportunity to investigate such phenomena. In 2023, the source had a very bright flare that triggered LST-1 and multi-wavelength data campaigns. In this study, we present the results of this observation campaign, in particular, the search for short-timescale variabilities.

A newly born millisecond magnetar has been proposed as one possible central engine of some gamma-ray bursts (GRBs) with X-ray plateau emission. In this work, we systematically analyzed the \emph{Swift}/XRT data of long GRBs with plateau emission that were detected before 2023 December, and estimated the magnetar parameters by considering the $R/I$ evolutionary effects, and investigated possible relationships among these parameters and their relation to the GRB jet and magnetar wind radiation. We found that neglecting the evolutionary effects of $R/I$ can lead to systematic overestimation or underestimation of magnetar parameters such as magnetic field strength ($B_p$), spin period ($P_0$), and ellipticity ($\epsilon$) from 20% to 50%. We also found that some tight correlations among different magnetar parameters, as well as between the GRB jet emission and the magnetar wind emission for our selected Equation of states (EoSs). The universal correlations suggest that a nascent magnetar with the faster $P_0$, lower $B_p$, and lower $\epsilon$ are more inclined to power more energetic GRB jet, and the ellipticity deformation and initial spin period of newborn magnetar are likely to originate from the magnetically-induced distortion and correspond to the equilibrium spin period as a result of interaction between the magnetar and its accretion disk, respectively. Finally, we found that the GW signals from the remnants of those GW-dominated GRBs with redshift measurements cannot reach aLIGO sensitivity threshold, and only two cases (GRBs 150323A and 170607A) can reach ET sensitivity threshold. Future GW observations could not only offer the first smoking gun that a protomagnetar can serve as the central engine of GRBs, but could also play a crucial role in precisely constraining the neutron EoS.

Type IIb supernovae (SNe) are a transitional subclass of stripped-envelope SNe showing hydrogen lines in their spectra that gradually weaken and give way to helium lines reminiscent of SNe Ib, which is indicative of stripping through stellar winds or binary interaction. SN 2024abfo is the seventh SN IIb with a direct progenitor detection. We find that the position of the supernova in our ERIS adaptive optics imaging agrees with the progenitor position in archival HST imaging to within 19 mas. The progenitor SED is consistent with an A5 giant. Single star models predict an initial mass in the range 11 to 15 solar masses, while the most probable binary model is a 12+1.2 solar mass system with an initial period of 1.73 years. We also find significant evidence for variability of the progenitor candidate in the years prior to core-collapse. SN 2024abfo is the least luminous SN IIb with a direct progenitor detections. At late times the r-band light curve decays more slowly than the comparison SNe, which may be due to increased gamma-ray trapping. Similar to SN 2008ax, SN 2024abfo does not show a prominent double-peaked light curve. Our semi-analytic light curve modelling shows that this may be due to a very low mass of hydrogen in the outer envelope. Spectrally, SN 2024abfo is most similar to SN 2008ax at early times while at later times (80 days) it appears to show persistent Halpha absorption compared to the comparison sample. We prefer a binary system to explain the supernova and its progenitor, although we are unable to rule out single-star models. We recommend late-time observations to search for a binary companion and signatures of CSM-interaction. The absence of these features would support the hypothesis that SN 2024abfo resulted from a system which underwent a period of binary mass transfer well before (1000 yr) the explosion, resulting in a low-mass hydrogen-rich envelope.

HF QPOs are among the most intriguing phenomena observed in LMXBs containing BHs or neutron stars. In this work, we investigate charged particles' dynamics in the nearby of a Schwarzschild-like BH embedded in a uniform magnetic field and surrounded on all sides by CDM. Thereby gaining deeper insight into the influence of magnetic and DM distributions on observable phenomena near compact objects. We first present a modified metric, which incorporates the effects of a CDM ... We compute the fundamental oscillation frequencies-radial, latitudinal, Keplerian, and Larmor-and demonstrate how their variation depends on the combined influence of CDM and magnetic field strength. The resulting frequency structure allows us to identify resonance radii associated with HF QPOs, particularly those in 3:2 ratios observed in microquasars. We assess several theoretical models for QPO generation, including the (ER), Relativistic Precession (RP), Tidal Disruption (TD), and Warped Disk (WD) models. A comparative fit of observational data from GRS 1915+105, H1743-322, XTE 1550-564, and GRO 1655-40 demonstrate that the TD and WD models provide the best match for HF QPOs in the presence of moderate magnetic flux ($B' = 0.1$), while the other models except ER fit better in weak-field scenarios. Our results highlight the importance of including both magnetic and dark matter (DM) effects in strong-field astrophysics and support the use of HF QPOs as sensitive probes of BH environments. This study opens new perspectives for exploring particle dynamics, accretion disk structure ...

Turbulence in protoplanetary disks affects dust evolution and planetesimal formation. The vertical shear instability (VSI) is one of the candidate turbulence-driving mechanisms in the outer disk region. Since the VSI requires rapid gas cooling, dust grains in disks can influence and potentially control VSI-driven turbulence. However, VSI-driven turbulence has strong vertical motion, causing vertical dust diffusion. As a result, it remains unclear how turbulent structures and dust distributions form. We aim to clarify whether the VSI can achieve a quasi-steady dust profile under cooling rate evolution associated with turbulently diffusing dust. We also elucidate the dependence of the dust size and dust-to-gas mass ratio on the realization and persistence of the equilibrium state. We perform global two-dimensional hydrodynamical simulations of an axisymmetric disk to investigate how the VSI drives turbulence and maintains a balance between dust settling and diffusion. These simulations account for the dynamic interplay between dust distribution, cooling rates, and turbulence. We find that VSI mixing, dust settling, and local cooling reach an equilibrium, forming a thick dust layer with a dimensionless vertical mixing coefficient of approximately 10^{-3}. The ability of the VSI to sustain this state also depends on the dust size and dust-to-gas mass ratio. Larger grains or lower mass ratios weaken turbulence, leading to dust settling. The condition of equilibrium state existence is consistent with the prediction of the semi-analytic model presented by Fukuhara & Okuzumi (2024). Our results indicate that efficient turbulent dust mixing and efficient cooling can occur simultaneously. They also imply that turbulence in VSI-dominated disks has different intensity levels depending on the grain size. This suggests that the efficiency of dust growth can depend on the VSI in protoplanetary disks.

In triple systems of weak hierarchies, nonlinear perturbations arising from the periodic oscillations associated with the inner and outer binaries play a crucial role in shaping their long-term dynamical evolution. In this context, we have developed an extended Brown Hamiltonian in Paper I, which serves as a fundamental model for describing the modified von Zeipel-Lidov-Kozai (ZLK) oscillations. The present work aims to analyze the characteristics of ZLK oscillations within this extended framework, focusing on phase-space structures, the location of ZLK center, the maximum eccentricity reached, the boundaries of librating cycles, and the critical inclination required to trigger ZLK resonance. Under the extended Hamiltonian, we introduce the Lidov integral C_ZLK, which is a combination of the Hamiltonian and the z-component of angular momentum, to characterize the modified ZLK properties. It is found that the librating and circulating cycles are separated by C_ZLK=0, which is consistent with the classical theory. Furthermore, we derive analytical expressions of these ZLK properties using perturbation techniques. Analytical predictions are compared to numerical results, showing an excellent agreement between them. Notably, the results reveal that ZLK characteristics in prograde and retrograde regimes are no longer symmetric under the influence of Brown corrections. At last, we conduct $N$-body integrations about millions of orbits to generate dynamical maps, where the numerical structures are well captured by the analytical solutions derived from the extended model.

In the framework of exploiting Very High Energy (VHE) gamma-ray observations of extragalactic sources to infer constraints on the intensity of cosmological background radiations, as well as on deviations from the standard model of particles and physical interactions (like violations of Lorentz invariance and axion-like particles -- LIV and ALPs), we discuss here possible contaminant effects due to the presence of radiations fields from local sources. We specifically model and analyze the foreground radiations produced inside the host galaxy of the VHE source and the cosmic environment itself hosting the source, as well as radiations produced in the Milky Way, along the VHE source's observational line-of-sights. Our analysis shows that such contaminant foregrounds may indeed impact on observations of only the very local Active Galactic Nuclei (e.g. Centaurus A), but not significantly those in the Virgo cluster (M87) and beyond.

Supernova remnants (SNRs) interacting with molecular clouds are interesting laboratories to study the acceleration of cosmic rays and their propagation in the dense ambient medium. We analyze 14 years of Fermi-LAT observations of the supernova remnant Puppis A to investigate its asymmetric $\gamma$-ray morphology and spectral properties. This middle-aged remnant ($\sim$4 kyr) is evolving in an inhomogeneous environment, interacting with a dense molecular cloud in the northeast and a lower-density medium in the southwest. We find clear differences in both $\gamma$-ray luminosity and spectral energy distribution between these two regions. The emission from both sides is consistent with a hadronic origin. However, while the southwestern emission can be explained by standard Diffusive Shock Acceleration (DSA), the northeastern side may involve re-acceleration of pre-existing cosmic rays or acceleration via reflected shocks in the dense cloud environment. Additionally, we identify two significant $\gamma$-ray excesses outside the remnant, including a previously unreported source to the south. These features are likely produced by cosmic rays that have escaped Puppis A and are interacting with nearby dense molecular material. From this extended emission, we estimate the total energy in escaping cosmic rays to be $W_{CR} \sim 1.5 \times 10^{49}$ erg, providing important constraints on cosmic-ray propagation around the remnant.

The variation in hot Jupiter (HJ) occurrence across stellar environments holds clues as to the dominant formation channels of these extreme planets. Recent studies suggest HJ hosts preferentially reside in regions of high phase space density, possibly reflecting natal environmental conditions. These regions are kinematically cold (|v| < 40 km/s), prompting the alternative hypothesis that the correlation reflects an age bias: planetary systems in overdensities are systematically younger and therefore less likely to have undergone tidal inspiral and destruction. We test whether the apparent excess of HJs in phase space overdensities arises from differences in intrinsic host properties -- mass, metallicity, age -- which may correlate with phase space density or whether there is evidence for an additional environmental effect. We derive homogeneous estimates for the mass, metallicity, and age of planet-hosting stars using 2MASS and Gaia DR3 photometry, parallaxes, and self-consistent spectroscopic and spectrophotometric observables. In a sample of 2265 confirmed exoplanet hosts, we find a significant relative excess of HJs orbiting stars in overdense regions. However, we also find that overdensities preferentially host younger, more massive, and more metal-rich stars compared to underdensities. After correcting for these differences, either by detrending the phase space density against age or by matching host properties across subsamples, we find no significant differences in the HJ populations between over- and underdense regions. Our results suggest that the previously reported correlation between HJ occurrence and phase space density is driven by underlying differences in host star demographics rather than an intrinsic environmental effect.

The source GS~1826-24 is a neutron star low mass X-ray binary known as the 'clocked burster' because of its extremely regular bursting behavior. We report on the detection of a long type-I X-ray burst from this source. We perform a detailed spectroscopic analysis of the long X-ray burst, lasting for $\sim 600$ s, seen in the NuSTAR observation carried out on 2022 September. The persistent emission is well described by an absorbed thermal Comptonization model (nthcomp), and the source exhibits a hard spectral state during this observation. The observed burst exhibits a rise time of $\sim 25$ s and a decay time of $\sim 282$ s. The time-resolved spectroscopy of the burst shows a significant departure from a pure thermal spectrum and is described with a model consisting of a varying-temperature blackbody plus an evolving persistent emission component. We observe a significant enhancement in the persistent emission during the burst. The enhancement of the pre-burst persistent flux is possibly due to Poynting-Robertson drag or coronal reprocessing. At the peak of the burst, the blackbody temperature and the blackbody emitting radius reached a maximum of $2.10\pm 0.07$ keV and $5.5\pm 2.1$ km, respectively. The peak flux ($F_{peak}$) during the burst is $\approx 2.4\times 10^{-8}$ ergs cm$^{-2}$ s$^{-1}$, which corresponds to a luminosity of $\approx 9.7\times 10^{37}$ ergs s$^{-1}$.

This work delves into the dynamical dark energy models of the wCDM parameterisation that are defined by their equation of state by comparing different, well-known parameterisation models, in an attempt to lessen the tensions of {H_0} and {\sigma_8} by using the latest observational data. This research also tested the newer Planck likelihood and BAO data by comparing them to their predecessors. The data that was used were: the Cosmic Microwave Background (CMB) data of Planck 2018 and Planck 2020 data; Cosmic Chronometers (CC), a sample of Supernovae Type Ia; and Baryonic Acoustic Oscillations (BAO). A Bayesian analysis was performed to produce the results needed for the analysis. From the analyses, the best-fit values of the parameters show that almost all models are in favour of a phantom Universe. This study also showed that the new tested data constrained the models better than the previous ones, while also showing that the observation data supports the {\Lambda}CDM model over the dynamical dark energy models

We present a new method and a corresponding code to compress the color magnitude diagram of a globular cluster into a representative curve, called a ridgeline, that can be more readily compared to isochrone models, among other applications. This compression method preserves the physical properties of the cluster, including the morphology of the CMD.

Io's tidally-driven global volcanism indicates widespread partial melting in its mantle. How this melt participates in the interior dynamics, and, in particular, the role it plays in tidal dissipation, is poorly understood. We model Io's tidal deformation by treating its mantle as a two-phase (solid and melt) system. By combining poro-viscous and poro-elastic compaction theories in a Maxwell framework with a consistent model of tidal and self-gravitation, we produce the first self-consistent evaluation of Io's tidal heating rate due to shearing, compaction, and Darcy flow. We find that Darcy dissipation can potentially exceed shear heating, but only for large (0.05 to 0.2) melt fractions, and if the grain size is large or melt viscosity ultra-low. Since grain sizes larger than 1~cm are unlikely, this suggests that Darcy dissipation is secondary to shear dissipation. Compaction dissipation is maximised when the asthenosphere is highly resistive to isotropic stresses, but contributes at most 1% of Io's observed heating rate. This work represents a crucial step toward a self-consistent quantitative theory for the dynamics of Io's partially molten interior.

Context. The one-dimensional treatment of turbulent convection had large successes until the early 2000s. However, the recent abundance and precision of observational data shows that this problem is far from solved. A modern approach should be developed by using multidimensional models. Aims. We established a new theoretical framework for comparison between one-dimensional and multidimensional convection models by mapping the two-dimensional structure of the convective zone and optimizing the modeling parameters of the SPHERLS code. Methods. We constructed a series of static envelope models for the same RR Lyrae stars, but with different horizontal sizes and resolutions. We then used a series of statistical methods to quantify the sizes of convective eddies, map the energy cascade, and describe the different structural parts of the convective zone. These include integral length scales, Fourier series, and the determination of the convective flux through horizontal averaging. Results. The structure of the convective zone depends significantly on the model size, below an angular size of $9^\circ$. The horizontal resolution of earlier studies is adequate to describe the granulation pattern in the large eddy simulation approach. In quasi-static RR Lyrae stars, the convective zone consists of two distinct dynamically unstable regions that are loosely connected. Approximately half of the convective flux is supplied by the transport of ionization energy in the partial hydrogen ionization zone. Conclusions. The 2D models presented in this work with the described size and resolution parameters can be used for comparison against 1D models. The structure of the convective zone urges reconsideration of some recent approaches to describe the convective flux currently used in radial stellar pulsation codes, which will be addressed in a separate paper.

Transition radiation is produced when a relativistic charged particle enters or leaves a solid medium. The electrons that produce synchrotron radiation may interact with the dust in circumstellar environments, leading to the emission of transition radiation. We explore the production of transition radiation in dusty novae that also display synchrotron radiation emission. Transition radiation is emitted in the hard ultra-violet/X-ray range. We suggest that, even when the transition radiation is not itself directly observable, it may have a role in determining the ionisation balance of, and grain heating in, nova ejecta. Furthermore, it may be important in other dusty environments (such as supernova remnants) with non-thermal radio emission.

The black hole X-ray binary MAXI J1820$+$070 began its first recorded outburst in March 2018, and remained an active radio, X-ray, and optical source for over four years. Due to the low distance to the source and its intrinsically high luminosity MAXI J1820$+$070 was observed extensively over this time period, resulting in high-cadence and quasi-simultaneous observations across the electromagnetic spectrum. These data sets provide the opportunity to probe the connection between accretion and the launch of jets in greater detail than for the majority of black hole X-ray binaries. In this work we present radio (Arcminute Microkelvin Imager Large Array, MeerKAT), X-ray (Swift), and optical (Las Cumbres Observatory) observations of MAXI J1820$+$070 throughout its entire outburst, including its initial hard state, subsequent soft state, and further hard-state-only re-brightenings (covering March 2018 to August 2022). Due to the regularity and temporal density of our observational data we are able to create a Radio - X-ray - Optical activity plane where we find a high degree of correlation between the three wave bands during the hard states, and observe hysteresis as MAXI J1820$+$070 enters and exits the soft state. Based on the morphology of the optical light curves we see evidence for optical jet contributions during the soft-to-hard state transition, as well as fading optical emission well before the hard to soft transition. We establish that the remarkably similar profiles of the re-brightening events are broadly consistent with modified disk instability models where irradiation from the inner accretion disk is included.

Vision Transformers are used via a customized TransUNet architecture, which is a hybrid model combining Transformers into a U-Net backbone, to achieve precise, automated, and fast segmentation of radio astronomy data affected by calibration and imaging artifacts, addressing the identification of faint, diffuse radio sources. Trained on mock radio observations from numerical simulations, the network is applied to the LOFAR Two-meter Sky Survey data. It is then evaluated on key use cases, specifically megahalos and bridges between galaxy clusters, to assess its performance in targeting sources at different resolutions and at the sensitivity limits of the telescope. The network is capable of detecting low surface brightness radio emission without manual source subtraction or re-imaging. The results demonstrate its groundbreaking capability to identify sources that typically require reprocessing at resolutions 4-6 times lower than that of the input image, accurately capturing their morphology and ensuring detection completeness. This approach represents a significant advancement in accelerating discovery within the large datasets generated by next-generation radio telescopes.

The paper describes the objectives, design and findings of the pre-launch ground characterisation campaigns of the Euclid infrared detectors. The pixel properties, including baseline, bad pixels, quantum efficiency, inter pixel capacitance, quantum efficiency, dark current, readout noise, conversion gain, response nonlinearity, and image persistence were measured and characterised for each pixel. We describe in detail the test flow definition that allows us to derive the pixel properties and we present the data acquisition and data quality check software implemented for this purpose. We also outline the measurement protocols of all the pixel properties presented and we provide a comprehensive overview of the performance of the Euclid infrared detectors as derived after tuning the operating parameters of the detectors. The main conclusion of this work is that the performance of the infrared detectors Euclid meets the requirements. Pixels classified as non-functioning accounted for less than 0.2% of all science pixels. IPC coupling is minimal and crosstalk between adjacent pixels is less than 1% between adjacent pixels. 95% of the pixels show a QE greater than 80% across the entire spectral range of the Euclid mission. The conversion gain is approximately 0.52 ADU/e-, with a variation less than 1% between channels of the same detector. The reset noise is approximately equal to 23 ADU after reference pixels correction. The readout noise of a single frame is approximately 13 $e^-$ while the signal estimator noise is measured at 7 $e^-$ in photometric mode and 9 $e^-$ in spectroscopic acquisition mode. The deviation from linear response at signal levels up to 80 k$e^-$ is less than 5% for 95% of the pixels. Median persistence amplitudes are less than 0.3% of the signal, though persistence exhibits significant spatial variation and differences between detectors.

Light pollution is an increasing environmental concern, impacting both ecological systems and human health. This report presents an analysis of light pollution data from the \textit{Was het donker} SQM network from 2020 until 2023, with a focus on indirect light pollution, commonly known as skyglow. By integrating measurements from Sky Quality Meter (SQM) stations in the network and cloud cover data from EUMETSAT, we conducted a comprehensive analysis of night sky brightness across a region encompassing northern Netherlands and the western part of the German Wadden Coast. Yearly changes in brightness for 27 locations were ranked and plotted, revealing that in the darkest areas, light pollution is increasing at a rate of 2.78 to 6.68 percent per year. A trend emerged showing that brighter areas experienced lower variability in brightness, while darker zones exhibited higher variability. This is due to the dominance of artificial light sources, such as street lighting, in brighter areas, which reduces the influence of natural light sources like the Moon, stars, and cloud backscatter. Seasonal patterns and the effects of the Milky Way were also investigated. Density plots were employed to visualize these changes in night sky brightness, helping to identify specific sources of light pollution, such as greenhouse lighting and streetlight turn-off times. These findings emphasize the need for systematic monitoring of light pollution and offer valuable insights that can guide public awareness initiatives and inform light pollution mitigation strategies.

Deriving accurate carbon abundance estimates for a wide variety of stars is still complex due to the difficulties in properly measuring it from atomic and molecular lines. The aim of this paper is to analyse the carbon abundance determination for the large empirical X-shooter Spectral Library (XSL), commonly used as a benchmark for the development of stellar population models. The analysis was performed over strong molecular CH bands in the G-band region. We used the GAUGUIN automated spectrum synthesis code, and adopted two different grids of reference synthetic spectra separately, each with the same [C/Fe] abundance coverage. We carried out a detailed comparison between both grids to evaluate the accuracy and the model dependence of the measured [C/Fe] abundances. We obtained a large and precise unbiased [C/Fe] abundance catalogue from both theoretical grids, well distributed in the Hertzsprung-Russell (HR) diagram and with no trend with the stellar parameters. We also measured compatible values from each independent CH band, with a high-quality [C/Fe] abundance estimate for both dwarfs and giants indistinctly. We observed a dispersed flat trend around [C/Fe] = 0.0 dex all along the metallicity regime, in agreement with some literature studies. However, we reported variations up to 0.8 dex in the [C/Fe] composition of the star depending on the adopted grid. We did not find such differences in the $\alpha$-element measurements. This behaviour implies a strong model dependence in the [C/Fe] abundance estimate. Potential sources of error could be associated with the use of spectral synthesis methods to derive stellar carbon abundances in the CH4300A band. Intrinsic small differences in the synthetic models over this crowded and blended region may induce a large disparity in the precise abundance estimate for any stellar type, leading to inaccurate carbon measurements without being noticed

Witness reports of Unidentified Aerial Phenomena (UAP) occasionally associate UAP sightings with local electromagnetic interferences, such as spinning magnetic compasses onboard aircraft or sudden malfunctions of mechanical vehicles. These reports have motivated the incorporation of a magnetometer into the instrumentation suite of the Galileo Project (GP), a Harvard-led scientific collaboration whose aim is to collect and analyze multi-sensor data that collectively could help elucidate the nature of UAP. The goal of the GP magnetometry investigation is to identify magnetic anomalies that cannot be readily explained in terms of a natural or human-made origin, and analyze these jointly with the data collected from the other modalities. These include an ensemble of visible and infrared cameras, a broadband acoustic system and a weather-monitoring system. Here, we present GP's first geomagnetic variometer station, deployed at the GP observatory in Colorado, USA. We describe the calibration and deployment of the instrumentation, which consists of a vector magnetometer and its data acquisition system, and the collection and processing of the data. Moreover, we present and discuss examples of the magnetic field data obtained over a period of 6 months, including data recorded during the May 2024 G5 extreme geomagnetic storm. We find that the data meet and even surpass the requirements laid out in GP's Science Traceability Matrix. Key to the evaluation of our data is the proximity of the variometer station to the USGS magnetic observatory in Boulder, Colorado. By comparing the two sets of data, we find that they are of similar quality. Having established the proper functioning of the first GP variometer station, we will use it as the model for variometer stations at future GP observatories.

Aims. Quasar catalogues from narrow-band photometric data are used in a variety of applications, including targeting for spectroscopic follow-up, measurements of supermassive black hole masses, or Baryon Acoustic Oscillations. Here, we present the final quasar catalogue, including redshift estimates, from the miniJPAS Data Release constructed using several flavours of machine-learning algorithms. Methods. In this work, we use a machine learning algorithm to classify quasars, optimally combining the output of 8 individual algorithms. We assess the relative importance of the different classifiers. We include results from 3 different redshift estimators to also provide improved photometric redshifts. We compare our final catalogue against both simulated data and real spectroscopic data. Our main comparison metric is the $f_1$ score, which balances the catalogue purity and completeness. Results. We evaluate the performance of the combined algorithm using synthetic data. In this scenario, the combined algorithm outperforms the rest of the codes, reaching $f_1=0.88$ and $f_1=0.79$ for high- and low-z quasars (with $z\geq2.1$ and $z<2.1$, respectively) down to magnitude $r=23.5$. We further evaluate its performance against real spectroscopic data, finding different performances. We conclude that our simulated data is not realistic enough and that a new version of the mocks would improve the performance. Our redshift estimates on mocks suggest a typical uncertainty of $\sigma_{\rm NMAD} =0.11$, which, according to our results with real data, could be significantly smaller (as low as $\sigma_{\rm NMAD}=0.02$). We note that the data sample is still not large enough for a full statistical consideration.

Modelling carbon monoxide (CO) line radiation is computationally expensive for traditional numerical solvers, especially when applied to complex, three-dimensional stellar atmospheres. We present COEmuNet, a 3D convolutional neural network (CNN)-based surrogate model that emulates CO line radiation transport with high accuracy and efficiency. It consists of an asymmetric encoder-decoder design that takes 3D hydrodynamical models as inputs and generates synthetic observations of evolved stellar atmospheres. The model is trained on data from hydrodynamic simulations of Asymptotic Giant Branch (AGB) stars perturbed by a companion. Given a set of input parameters, including velocity fields, kinetic temperature distribution, and CO molecular number densities, the COEmuNet model emulates spectral line observations with a median relative error of ~7% compared to a classical numerical solver of the radiative transfer equation, measured over seven frequency channels and arbitrary viewing directions. Besides, COEmuNet delivers a 1000 times speedup, enabling efficient model fitting to observational datasets, real-time visualization of simulations and progress toward integration in large-scale cosmological simulations.

The application of convolutional autoencoder deep learning to imaging data for planetary science and astrobiological use is briefly reviewed and explored with a focus on the need to understand algorithmic rationale, process, and results when machine learning is utilized. Successful autoencoders train to build a model that captures the features of data in a dimensionally reduced form (the latent representation) that can then be used to recreate the original input. One application is the reconstruction of incomplete or noisy data. Here a baseline, lightweight convolutional autoencoder is used to examine the utility for planetary image reconstruction or inpainting in situations where there is destructive random noise (i.e., either luminance noise with zero returned data in some image pixels, or color noise with random additive levels across pixel channels). It is shown that, in certain use cases, multi-color image reconstruction can be usefully applied even with extensive random destructive noise with 90% areal coverage and higher. This capability is discussed in the context of intentional masking to reduce data bandwidth, or situations with low-illumination levels and other factors that obscure image data (e.g., sensor degradation or atmospheric conditions). It is further suggested that for some scientific use cases the model latent space and representations have more utility than large raw imaging datasets.

We consider a general dark energy (DE) model parametrized by its equation-of-state (EoS), featuring three free parameters: $w_0$ (the present-day value of the DE EoS), $w_{\beta}$ (quantifying the dynamical nature of the DE EoS), and $\beta$ (governing various dynamical forms of the DE EoS). The key controlling parameter $\beta$ can recover several existing DE models in the literature, such as the Chevallier-Polarski-Linder (CPL) parametrization ($\beta = 1$), the logarithmic parametrization (in the limit $\beta \rightarrow 0$), and the linear parametrization ($\beta = -1$), alongside generate a class of new DE parametrizations for other values of $\beta$. The resulting DE scenario is constrained using a suite of the latest cosmological probes, including Cosmic Microwave Background (CMB) temperature and polarization anisotropies from three different experiments (Planck 2018 and Atacama Cosmology Telescope combined with WMAP), CMB lensing, Baryon Acoustic Oscillations from DESI Year 2, and PantheonPlus from Type Ia supernovae. Our analyses reveal that stringent constraints on the DE parameters are obtained only when all cosmological probes are combined; otherwise, some parameters remain unconstrained. The present-day value of the DE EoS remains in the quintessence regime according to our results, and no significant evidence for a dynamical DE EoS is found. However, based on the $\Delta\chi^2$ and Bayesian evidence analyses, we observe a mild preference for the present three-parameter DE parametrization over the CPL parametrization when all cosmological probes are taken into account. Nonetheless, the Bayesian evidence difference remains below the threshold for statistical significance according to the revised Jeffreys scale, indicating that both models are effectively equally preferred by the data.

Gamma-ray binaries present emission that is variable and can reach UHE. The processes behind the acceleration of the particles that produce this very energetic radiation are yet to be understood. We probe the properties of the particle accelerator and the UHE photon emitter in the gamma-ray binary LS 5039. From the properties of the binary system and the UHE radiation detected by HAWC, we used analytical tools to investigate how these properties constrain the emission and acceleration regions, namely the role of synchrotron losses, particle confinement, and the accelerated particle spectrum, and propose an acceleration scenario that can relax the derived constraints. The modest target densities for hadronic processes and the overall gamma-ray orbital variability favor inverse Compton scattering of ultraviolet photons from the massive companion star by highly relativistic electrons. The acceleration of the highest energy electrons implies a constraint on synchrotron cooling in the acceleration region, which can set an upper limit on its magnetic field. Moreover, the detected variability requires very strong particle confinement in both the acceleration and emission regions, which sets a lower limit on their magnetic fields that is barely consistent with the synchrotron cooling constraint from acceleration. Synchrotron losses may be higher in the emitting region if it is separated from the accelerator, but this requires a very hard particle injection spectrum. A scenario for LS 5039 of the kind proposed by Derishev and collaborators, in which an ultrarelativistic magnetized outflow accelerates leptons injected within the outflow by gammagamma absorption, provides a viable mechanism to accelerate very energetic electrons. This mechanism relaxes the acceleration and confinement requirements by reducing the impact of synchrotron cooling, and can generate the required particle spectrum.

The Laser Interferometer Space Antenna (LISA) will detect ~ 100 galactic binary systems comprised of black holes (BHs) and neutron stars (NSs). Identifying the nature of the constituents of these binaries as BHs or NSs, and distinguishing them from $\sim 10^4$ detected double white dwarfs will be challenging. In the absence of any other information, the inferred values of the component masses can be used to classify the nature of these objects. However, short-period galactic binaries $\sim 10^7 - 10^3$ yr from coalescence produce a quasi-monochromatic signal which carries little information about their masses. We generate synthetic LISA data sets containing gravitational waves (GWs) from galactic binary BHs, binary NSs and BHNSs drawn from an astrophysically realistic population produced through the isolated binary evolution channel. We process the data with an end-to-end Bayesian inference pipeline to explore the accuracy with which the individual component masses can be measured. We find that for $\approx 10\% - 50\%$ of the detected systems LISA will be able to measure the individual component masses by measuring the orbital eccentricity, periapse precession frequency, and GW induced frequency derivative. Typical fractional mass errors are $\approx 1\% - 100\%$ (depending on the specific value of the source parameters), which will enable in many circumstances the classification of the objects as BHs or NSs. For these binaries, LISA will also be able to determine their 3-dimensional position in the Milky Way. The LISA-detected sample of these double compact objects will provide new information about the galactic population of BHs and NSs, the star formation history of the Milky Way and the astrophysical processes leading to the formation of these systems. However, for a significant fraction of the LISA-detected binaries the nature of their constituent objects may remain unclear.

Spectroscopic redshift surveys are key tools to trace the large-scale structure (LSS) of the Universe and test the $\Lambda$CDM model. However, using redshifts as distance proxies introduces distortions in the 3D galaxy distribution. If uncorrected, these distortions lead to systematic errors in LSS analyses and cosmological parameter estimation. We present a new method that combines linear theory (LT) and a neural network (NN) to mitigate redshift space distortions (RSDs). The hybrid LT+NN approach is trained and validated on dark matter halo fields from z = 1 snapshots of the Quijote N-body simulations. LT corrects large-scale distortions in the linear regime, while the NN learns quasi-linear and small-scale features. The LT correction is applied first, then the NN is trained on the resulting fields to improve accuracy across scales. The method uses a Mean Squared Error (MSE) loss and yields significant performance gains: approximately 50% improvement over LT alone and 12% over NN alone. The reconstructed fields from the LT+NN method show stronger correlations with the true real-space fields than either LT or NN separately. The hybrid method also improves clustering statistics such as halo-halo and halo-void correlations, with benefits extending to BAO scales. Compared to NN-only, it provides better suppression of spurious anisotropies on large and quasi-linear scales, as measured by the quadrupole moments of correlation functions. This work shows that combining a physically motivated dynamical model with a machine learning algorithm leverages the strengths of both approaches. The LT+NN method achieves high accuracy with modest training data and computational cost, making it a promising tool for future applications to more realistic galaxy surveys.

We present CRPropa 3.3, the latest release of the publicly available Monte Carlo framework for simulating the propagation of high-energy particles in astrophysical environments. This version introduces significant extensions that enables multi-messenger studies across a broad energy range, from GeV to ZeV. New features include explicit time tracking, time-dependent advection fields, and support for position-dependent radiation backgrounds, for more realistic simulations of Galactic and extragalactic propagation. Nuclear cross sections have been updated and expanded up to lead (Z=82). We illustrate some of these new features, including acceleration at moving shocks and gamma-ray propagation in the interstellar radiation field. Together, these improvements establish CRPropa 3.3 as a comprehensive tool for modelling cosmic rays, gamma rays, and their secondaries in structured, time-dependent environments, setting the stage for next-generation multi-messenger astrophysics.

It has been established that a significant fraction of star formation at high-redshift occurs in clumpy galaxies. The properties of clumps and their formation mechanisms, however, remain highly debated. In this work we analyze a sample of 18 Supercompact Ultraviolet Luminous Galaxies observed with the OSIRIS spectrograph at the Keck Telescope, targeting their Pa-alpha emission. These galaxies, although at z~0.1-0.2, share many similar properties with star-forming galaxies at cosmic noon. We find a total of 84 star-forming clumps with typical sizes of a few hundred parsecs. The star-forming clumps exhibit low values of velocity shear (~12 km/s) and high velocity dispersion (~70 km/s). The dynamical masses of the clumps are typically higher than gas masses inferred from the measured star-formation rates of each clump. We also artificially redshift our data to emulate observations at z=2.2 and allow for a direct comparison with other galaxies at higher redshift. Our results indicate that, due to the effects of clump clustering and low-resolution observations, high-z clumps appear larger at greater cosmological distances. This underscores the importance of using low-redshift observations to anchor studies at earlier epochs. Finally, our results support the idea of growing clump sizes in star-forming galaxies as a function of redshift, although not to scales of kpc as found by other works without the benefits of adaptive optics or gravitational lensing.

We report the detection and characterization of TOI-201 c, a long-period transiting companion to the warm Jupiter TOI-201 b. Its presence was first inferred from high-amplitude transit timing variations (TTVs) in TOI-201 b, pointing to a massive outer body on a $7.7^{+1.0}_{-0.6}$-year eccentric orbit. This prediction was confirmed when TESS observed a transit of TOI-201 c, precisely constraining its orbital geometry. A joint fit to TTVs, transit photometry, and archival radial velocities yields a mass of $14.2^{+1.0}_{-1.2}$ $M_{\rm Jup}$ and an eccentricity of $0.643^{+0.009}_{-0.021}$. The mutual inclination between planets b and c is $2.9^{+4.8}_{-4.4}$ degrees, indicating a nearly coplanar architecture. Long-term numerical integrations confirm dynamical stability over gigayear timescales and predict that transits of TOI-201 b will cease within a few thousand years. TOI-201 c ranks among the longest-period transiting planets with well-constrained properties. Its detection via TTVs, followed by a confirmed transit, represents a rare observational sequence and highlights the power of TTVs and photometric monitoring to uncover distant companions. The TOI-201 system offers a valuable laboratory for testing models of giant planet formation, migration, and secular evolution in multi-planet systems.

The Cosmic Distance Duality Relation (CDDR) connects the angular diameter distance ($d_A$) and the luminosity distance ($d_L$) at a given redshift. This fundamental relation holds in any metric theory of gravity, provided that photon number is conserved and light propagates along null geodesics. A deviation from this relation could indicate new physics beyond the standard cosmological model. In this work, we test the validity of the CDDR at very low redshifts ($z < 0.04$) by combining $d_A$ from the Megamaser Cosmology Project with $d_L$ from the Pantheon+ sample of Type Ia Supernovae (SNIa). We find the relation to be statistically consistent with the current data. We further incorporate high-redshift Baryon Acoustic Oscillation (BAO)-based $d_A$ measurements from DESI DR2 in combination with SNIa data, highlighting the critical role of the $r_d-M_b$ (early-late) calibration in testing the CDDR using these two probes. Assuming CDDR holds, we perform a Bayesian analysis to derive model-independent constraints on the calibration parameters. Using only BAO and SNIa data, we observe a strong degeneracy between $r_d$ and $M_b$. However, the inclusion of calibration-free Megamaser measurements breaks this degeneracy, enabling independent constraints without relying on a specific cosmological model or distance-ladder techniques. Additionally, we present a forecast incorporating the expected precision from future Megamaser and SNIa observations, demonstrating their potential to significantly tighten constraints on early-late calibration parameters, under the assumption of validity of CDDR.

The interiors of neutron stars enjoy ideal conditions for the conversion of hadrons to a strange quark phase, theorized to be the stablest form of matter. Though numerous astrophysical means to prompt such a deconfinement phase transition have been suggested, they may be pre-empted by a large energy barrier for nucleation of quark matter droplets. We will show that interactions of hidden sectors of particles with nucleons may surmount the barrier if it exceeds deca-GeV energies, and spark a phase transition. The neutron star would then, depending on the equation of state of QCD matter, convert to a black hole and/or set off a gamma-ray burst (GRB). Using the observed existence of ancient neutron stars and estimates of the GRB rate, we then set some of the strictest (albeit conditional) limits on dark matter scatters, annihilations, and decays that are tens of orders stronger than those from terrestrial searches. For smaller energy barriers, lower limits on nucleon decay lifetimes of the order of $10^{64}$~yr may be obtained

This chapter introduces gravitational wave cosmology, focusing on the use of gravitational waves as standard sirens to probe the expansion history of the Universe. It presents and explains the methodologies behind bright and dark siren analyses, including their respective data requirements and underlying assumptions. Particular attention is given to the theoretical foundations of these approaches, the statistical frameworks used to interpret gravitational-wave events, and the treatment of selection effects. Examples and applications are provided for each method, with the aim of offering a clear and accessible introduction to the tools and concepts enabling cosmological inference from gravitational-wave observations.

The empty, extensive low-density lattice topology of hemoglycin is examined to understand how in space, and possibly as early as 800M years into cosmic time a rod-like polymer of glycine and iron came into dominance. A central question to be answered is whether the hemoglycin rod lattice with diamond 2H symmetry represents the most efficient covering of space by a regular arrangement of identical rods. Starting from the tetrahedral symmetry of every hemoglycin lattice vertex we find that the regular truncated tetrahedron of Archimedes may be expanded until neighboring hexagon faces are coincident, at which point space filling is 23/24 or 95.8333% complete. We describe the unit cells of the diamond 2H rod lattice and its conforming near-complete space-filling structure, which has identical symmetry. Maximum space filling via a minimum of molecular material can allow hemoglycin to drive accretion in molecular clouds, contributing to the composition of dust, and providing a background for its widespread presence in meteoritic samples and in cometary material that falls to Earth. The optical properties of hemoglycin lattice entities are derived from quantum calculations of ultraviolet and visible transition energies and strengths. The hemoglycin extinction curve duplicates the nominal 218nm ultraviolet absorption feature known as the UV bump, together with two visible absorption features present in a generic compilation of astronomical extinction data.

We present a framework based on the standard type-I seesaw model that relates the baryon asymmetry of the universe to the dark matter (DM) density. The framework, which we name "Asymgenesis", relies on the presence of primordial charge asymmetries seeded either in the dark sector or in the visible sector. A higher-dimensional portal operator reshuffles this initial asymmetry into both sectors, eventually resulting in a nonzero $B-L$ asymmetry and an asymmetric DM component. Compared to conventional asymmetric-dark-matter (ADM) schemes, our framework imposes far milder requirements on the portal interaction. In particular, the portal interaction need not violate $B-L$, and the temperature scales of efficient $B-L$ violation and efficient charge-transfer interaction mediated by the portal operator can be separated. We develop the formalism in detail and argue that the flexibility of our framework enlarges the model-building landscape for ADM.

Observations of the hydrogen hyperfine transition through the 21 cm line near the end of the cosmic dark ages provide unique opportunities to probe new physics. In this work, we investigate the potential of the sky-averaged 21 cm signal to constrain metastable particles produced in the early universe that decay at later times, thereby modifying the thermal and ionization history of the intergalactic medium. The study begins by extending previous analyses of decaying dark matter (DM), incorporating back-reaction effects and tightening photon decay constraints down to DM masses as low as 20.4 eV. The focus then shifts to non-minimal dark sectors with multiple interacting components. The analysis covers two key scenarios: a hybrid setup comprising a stable cold DM component alongside a metastable sub-component, and a two-component dark sector of nearly degenerate states with a metastable heavier partner. A general parameterization based on effective mass spectra and fractional densities allows for a model-independent study. The final part presents two explicit realizations: an axion-like particle coupled to photons, and pseudo-Dirac DM interacting via vector portals or electromagnetic dipoles. These scenarios illustrate how 21 cm cosmology can set leading bounds and probe otherwise inaccessible regions of parameter space.

We develop a first-principles formalism, based on the transport equation in the line-of-sight approximation, to link the expected number of muons at neutrino telescopes to the flux of neutrinos at the Earth surface. We compute the distribution of muons inside Earth, arising from the up-scattering of neutrinos close to the detector, as well as from the decay of taus produced farther away. This framework allows one to account for systematic uncertainties, as well as to clarify the assumptions behind definitions commonly used in literature, such as the effective area. We apply this formalism to analyze the high-energy muon event recorded by KM3NeT, with a reconstructed energy of $ 120^{+110}_{-60} \, \mathrm{PeV}$ and an elevation angle of $\left(0.54\pm 2.4\right)^\circ$, in comparison with the non-observation of similar events by IceCube. We find a $3.1\,\sigma$ tension between the two experiments, assuming a diffuse neutrino source with a power-law energy dependence. Combining both datasets leads to a preference for a very low number of expected events at KM3NeT, in stark contrast to the observed data. The tension increases both in the case of a diffuse source peaking at the KM3NeT energy and of a steady point source, whereas a transient source may reduce the tension down to $1.6\,\sigma$. The formalism allows to treat potential beyond-the-Standard-Model sources of muons, and we speculate on this possibility to explain the tension.

Gravitational waves emitted in the late inspiral of binary neutron stars are affected by their tidal deformation. We study the tidal dynamics in full general relativity through matched-asymptotic expansions and prove that the dynamical tidal response can be expanded in a complete set of modes. We further prove that the mode amplitudes satisfy an effective, forced harmonic oscillator equation, which generalizes the overlap-integral formulation of Newtonian gravity. Our relativistic treatment of dynamical tides will avoid systematic biases in future gravitational-wave parameter estimation.

Exoplanets with a long orbital period are difficult to discover by extant methods. Our first publication (Lerner, P., A. Mayer, T. E. Sullivan. 2023. A new method for the discovery of the distant exoplanets. SPIE Proceedings 12680: 126802(M)) proposed a Hanbury-Brown-Twiss (HBT) interferometry-inspired method to find exoplanets with a very slow-changing influence on their host star. Traditional HBT interferometry measured the modulus of the correlation function. Slight modification of the HBT can determine its real part. Simultaneous observation of both characteristics, e.g. in a binocular setting of telescopes, is exceptionally sensitive to the asymmetry of the luminous object. However, the issue of a very small signal-to-noise ratio (SNR) for HBT makes application of this method difficult. In the current paper, we discuss the possibilities to enhance the low SNR of the method.

Ultra-high energy (UHE) photons above 10^{18} eV serve as valuable probes of fundamental physics. While typically produced in interactions involving charged particles, they could also originate from exotic sources such as annihilations of magnetically charged monopole-antimonopole pairs or decays of highly accelerated monopoles (10^{21} eV). Detecting such photons would impose constraints on monopole properties. Despite strong theoretical motivations and extensive experimental searches, no monopoles have been observed to date. A possible explanation beyond high monopole masses arises from Staruszkiewicz's quantum theory of infrared electromagnetic fields. His argument, rooted in the positivity of the Hilbert space norm, suggests that isolated magnetic monopoles may not be physically realizable. If correct, this would imply that while monopoles remain mathematically well-defined within field theories, only magnetically neutral configurations could exist in nature.

The scalability of most transition-edge sensor arrays is limited by the multiplexing technology which combines their signals over a reduced number of wires and amplifiers. In this letter, we present and demonstrate a multiplexer design optimized for transition-edge sensor bolometers with 1820 sensors per readout unit, a factor of two larger than the previous state-of-the-art. The design is optimized for cosmic microwave background imaging applications, and it builds on previous microwave superconducting quantum interference device multiplexers by doubling the available readout bandwidth to the full 4--8 GHz octave. Evaluating the key performance metrics of yield, sensitivity, and crosstalk through laboratory testing, we find an end-to-end operable detector yield of 78%, a typical nearest-neighbor crosstalk amplitude of $\sim$0.4%, and a median white noise level of 83 pA/$\sqrt{\mathrm{Hz}}$ due to the multiplexer, corresponding to an estimated contribution of 4% to the total system noise for a ground-based cosmic microwave background telescope. Additionally, we identify a possible path toward reducing resonator loss for future designs with reduced noise.

The detection of gravitational waves by the LIGO-Virgo-KAGRA collaboration has ushered in a new era of observational astronomy, emphasizing the need for rapid and detailed parameter estimation and population-level analyses. Traditional Bayesian inference methods, particularly Markov chain Monte Carlo, face significant computational challenges when dealing with the high-dimensional parameter spaces and complex noise characteristics inherent in gravitational wave data. This review examines the emerging role of simulation-based inference methods in gravitational wave astronomy, with a focus on approaches that leverage machine-learning techniques such as normalizing flows and neural posterior estimation. We provide a comprehensive overview of the theoretical foundations underlying various simulation-based inference methods, including neural posterior estimation, neural ratio estimation, neural likelihood estimation, flow matching, and consistency models. We explore the applications of these methods across diverse gravitational wave data processing scenarios, from single-source parameter estimation and overlapping signal analysis to testing general relativity and conducting population studies. Although these techniques demonstrate speed improvements over traditional methods in controlled studies, their model-dependent nature and sensitivity to prior assumptions are barriers to their widespread adoption. Their accuracy, which is similar to that of conventional methods, requires further validation across broader parameter spaces and noise conditions.

GeV-scale thermal dark matter (DM) is highly constrained by the null results of both direct and indirect detection experiments, especially in the context of simplified models. In this work, we study the interplay of collider, direct and indirect detection constraints on an extension of the dark Abelian Higgs model that includes a Dirac fermionic DM candidate, $\chi$. We take into account in a consistent fashion the dilution of the indirect and direct detection signals when the relic abundance of $\chi$ is smaller than the total observed DM density (assuming that it is a subdominant component in those cases). As a consequence, we show that indirect detection constraints cannot probe regions with large kinetic mixing, and direct detection experiments provide the leading constraints in most of the parameter space. Collider searches for the (invisibly decaying) vector mediator provide complementary bounds in areas with large kinetic mixing. We find that the only way to avoid both indirect and direct detection limits is in narrow windows of parameter space close to $m_\chi\lesssim m_{Z_D}/2$, when $\chi$ is produced resonantly in the early universe, and it can constitute all of the DM. For this to happen, a small dark sector coupling is required: $\alpha_D~\lesssim10^{-3}$ for DM masses below $6$ GeV, or $\alpha_D~\lesssim10^{-5}$ for DM masses larger than $10$ GeV. The remaining areas of the parameter space can be probed in a complementary way by future direct detection experiments (which will narrow down the allowed area around the resonant region) and collider searches (which will set limits for smaller values of the kinetic mixing).