Papers for Friday, Dec 13 2024

We present timing solutions spanning nearly two decades for five redback (RB) systems found in globular clusters (GC), created using a novel technique that effectively "isolates" the pulsar. By accurately measuring the time of passage through periastron ($T_0$) at points over the timing baseline, we use a piecewise-continuous, binary model to get local solutions of the orbital variations that we pair with long-term orbital information to remove the orbital timing delays. The isolated pulse times of arrival can then be fit to describe the spin behavior of the millisecond pulsar (MSP). The results of our timing analyses via this method are consistent with those of conventional timing methods for binaries in GCs as demonstrated by analyses of NGC 6440D. We also investigate the observed orbital phase variations for these systems. Quasi-periodic oscillations in Terzan 5P's orbit may be the result of changes to the gravitational-quadruple moment of the companion as prescribed by the Applegate model. We find a striking correlation between the standard deviation of the phase variations as a fraction of a system's orbit ($\sigma_{\Delta T_0}$) and the MSP's spin frequency, as well as a potential correlation between $\sigma_{\Delta T_0}$ and the binary's projected semi-major axis. While long-term RB timing is fraught with large systematics, our work provides a needed alternative for studying systems with significant orbital variations, especially when high-cadence monitoring observations are unavailable.

Essential information about the formation and evolution of planetary systems can be found in their architectures -- in particular, in stellar obliquity ($\psi$) -- as they serve as a signature of their dynamical evolution. Here, we present ESPRESSO observations of the Rossiter-Mclaughlin (RM) effect of 8 warm gas giants, revealing that independent of the eccentricities, all of them have relatively aligned orbits. Our 5 warm Jupiters -- WASP-106 b, WASP-130 b, TOI-558 b, TOI-4515 b, and TOI-5027 b -- have sky-projected obliquities $|\lambda|\simeq0-10$ deg while the 2 less massive warm Saturns -- K2-139 b and K2-329 A b -- are slightly misaligned having $|\lambda|\simeq15-25$ deg. Furthermore, for K2-139 b, K2-329 A b, and TOI-4515 b, we also measure true 3D obliquities $\psi\simeq15-30$ deg. We also report a non-detection of the RM effect produced by TOI-2179 b. Through hierarchical Bayesian modeling of the true 3D obliquities of hot and warm Jupiters, we find that around single stars, warm Jupiters are statistically more aligned than hot Jupiters. Independent of eccentricities, 95\% of the warm Jupiters have $\psi\lesssim30$ deg with no misaligned planets, while hot Jupiters show an almost isotropic distribution of misaligned systems. This implies that around single stars, warm Jupiters form in primordially aligned protoplanetary disks and subsequently evolve in a more quiescent way than hot Jupiters. Finally, we find that Saturns may have slightly more misaligned orbits than warm Jupiters, but more obliquity measurements are necessary to be conclusive.

We present GalSBI, a phenomenological model of the galaxy population for cosmological applications using simulation-based inference. The model is based on analytical parametrizations of galaxy luminosity functions, morphologies and spectral energy distributions. Model constraints are derived through iterative Approximate Bayesian Computation, by comparing Hyper Suprime-Cam deep field images with simulations which include a forward model of instrumental, observational and source extraction effects. We developed an emulator trained on image simulations using a normalizing flow. We use it to accelerate the inference by predicting detection probabilities, including blending effects and photometric properties of each object, while accounting for background and PSF variations. This enables robustness tests for all elements of the forward model and the inference. The model demonstrates excellent performance when comparing photometric properties from simulations with observed imaging data for key parameters such as magnitudes, colors and sizes. The redshift distribution of simulated galaxies agrees well with high-precision photometric redshifts in the COSMOS field within $1.5\sigma$ for all magnitude cuts. Additionally, we demonstrate how GalSBI's redshifts can be utilized for splitting galaxy catalogs into tomographic bins, highlighting its potential for current and upcoming surveys. GalSBI is fully open-source, with the accompanying Python package, $\texttt{galsbi}$, offering an easy interface to quickly generate realistic, survey-independent galaxy catalogs.

Even after decades of usage as an extragalactic standard candle, the universal bright end of the planetary nebula luminosity function (PNLF) still lacks a solid theoretical explanation. Until now, models have modeled planetary nebulae (PNe) from artificial stellar populations, without an underlying cosmological star formation history. We present PICS (PNe In Cosmological Simulations), a novel method of modeling PNe in cosmological simulations, through which PN populations for the first time naturally occur within galaxies of diverse evolutionary pathways. We find that only by using realistic stellar populations and their metallicities is it possible to reproduce the bright end of the PNLF for all galaxy types. In particular, the dependence of stellar lifetimes on metallicity has to be accounted for to produce bright PNe in metal-rich populations. Finally, PICS reproduces the statistically complete part of the PNLF observed around the Sun, down to six orders of magnitude below the bright end.

Magnetic fields play an important role in the evolution of galaxies and in shaping the dynamics of their inter-stellar medium. However, the formation history of magnetic fields from initial seed-fields to well-ordered systems is not clear. Favoured scenarios include a turbulent dynamo that amplifies the field, and a mean-field dynamo that organizes it. Such a model can be tested through observing the magnetic-field structure of galaxies in the early Universe given the relative formation time-scales involved. Here, we combine the high angular resolution of the Atacama Large Milli-metre Array (ALMA) and gravitational lensing to resolve the magnetic field structure of a 4-kpc in extent grand-design spiral when the Universe was just 2.6 Gyr old. We find that the spiral arm structure, as traced by the heated dust emission, is coincident with the linearly polarized emission, which is consistent with a highly ordered magnetic field. The time-scale needed to produce such an ordered field is likely within at least several rotations of the disk. Our study highlights the importance of combining the long baselines of ALMA and gravitational lensing to resolve the structure of galaxies at cosmologically interesting epochs.

Superclusters are the most massive structures in the universe. To what degree they are actually bound against an accelerating expansion of the background is of significant cosmological and astrophysical interest. In this study, we introduce a cross matched set of superclusters from the SLOW constrained simulations of the local (z<0.05) universe. Identifying the superclusters provides estimates on the efficacy of the constraints in reproducing the local large-scale structure accurately. The simulated counterparts can help identifying possible future observational targets containing interesting features such as bridges between pre-merging and merging galaxy clusters and collapsing filaments and provide comparisons for current observations. By determining the collapse volumes for the superclusters we further elucidate the dynamics of cluster-cluster interactions in those regions. Using catalogs of local superclusters and the most massive simulated clusters, we search for counterparts of supercluster members of six regions. We evaluate the significance of these detections by comparing their geometries to supercluster regions in random simulations. We then run an N-body version of the simulation into the far future and determine which of the member clusters are gravitationally bound to the host superclusters. Furthermore we compute masses and density contrasts for the collapse regions. We demonstrate the SLOW simulation of the local universe to accurately reproduce local supercluster regions in mass of their members and three-dimensional geometrical arrangement. We furthermore find the bound regions of the local superclusters consistent in size and density contrast with previous theoretical studies. This will allow to connect future numerical zoom-in studies of the clusters to the large scale environments and specifically the supercluster environments these local galaxy clusters evolve in.

We analyze the fractal dimension of open clusters using 3D spatial data from Gaia DR3 for 93 open clusters from Pang et al. (2024) and 127 open clusters from Hunt & Reffert (2024) within 500 pc. The box-counting method is adopted to calculate the fractal dimension of each cluster in three regions: the all-member region, $r \leq r_t$ (inside the tidal radius), and $r > r_t$ (outside the tidal radius). In both the Pang and Hunt catalogs, the fractal dimensions are smaller for the regions $r > r_t$ than those for $r \leq r_t$, indicating that the stellar distribution is more clumpy in the cluster outskirts. We classify cluster morphology based on the fractal dimension via the Gaussian Mixture Model. Our study shows that the fractal dimension can efficiently classify clusters in the Pang catalog into two groups. The fractal dimension of the clusters in the Pang catalog declines with age, which is attributed to the development of tidal tails. This is consistent with the expectations from the dynamical evolution of open clusters. We find strong evidence that the fractal dimension increases with cluster mass, which implies that higher-mass clusters are formed hierarchically from the mergers of lower-mass filamentary-type stellar groups. The transition of the fractal dimension for the spatial distribution of open clusters provides a useful tool to trace the Galactic star forming structures, from the location of the Local Bubble within the solar neighborhood to the spiral arms across the Galaxy.

Letters of recommendation are a common tool used in graduate admissions. Most admissions systems require three letters for each applicant, burdening both letter writers and admissions committees with a heavy work load that may not be time well-spent. Most applicants do not have three research advisors who can comment meaningfully on research readiness, adding a large number of letters that are not useful. Ideally, letters of recommendation will showcase the students' promise for a research career, but in practice, the letters often do not fulfill this purpose. As a group of early and mid-career faculty who write dozens of letters every year for promising undergraduates, we are concerned and overburdened by the inefficiencies of the current system. In this open letter to the AAS Graduate Admissions Task Force, we offer an alternative to the current use of letters of recommendation: a portfolio submitted by the student, which highlights e.g., a paper, plot, or presentation that represents their past work and readiness for grad school, uploaded to a centralized system used by astronomy and astrophysics PhD programs. While we argue that we could eliminate letters in this new paradigm, it may instead be advisable to limit the number of letters of recommendation to one per applicant.

With the rise of simulation-based inference (SBI) methods, simulations need to be fast as well as realistic. $\texttt{UFig v1}$ is a public Python package that generates simulated astronomical images with exceptional speed - taking approximately the same time as source extraction. This makes it particularly well-suited for simulation-based inference (SBI) methods where computational efficiency is crucial. To render an image, $\texttt{UFig}$ requires a galaxy catalog and a description of the point spread function (PSF). It can also add background noise, sample stars using the Besançon model of the Milky Way, and run $\texttt{SExtractor}$ to extract sources from the rendered image. The extracted sources can be matched to the intrinsic catalog, flagged based on $\texttt{SExtractor}$ output and survey masks, and emulators can be used to bypass the image simulation and extraction steps. A first version of $\texttt{UFig}$ was presented in Bergé et al. (2013) and the software has since been used and further developed in a variety of forward modelling applications.

Thanks to Integral Field Unit survey data it is possible to explore in detail the link between the formation of the stellar content in galaxies and the drivers of evolution. Traditionally, scaling relations have connected galaxy-wide parameters such as stellar mass (M$_s$), morphology or average velocity dispersion ($\sigma$) to the star formation histories (SFHs). We study a high quality sample of SDSS-MaNGA spectra to test the possibility that sub-galaxy ($\sim$2\,kpc) scales are dominant, instead of galaxy-wide parameters. We find a strong correlation between local velocity dispersion and key line strengths that depend on the SFHs, allowing us to make the ansatz that this indicator - that maps the local gravitational potential - is the major driver of star formation in galaxies, whereas larger scales play a role of a secondary nature. Galactocentric distance has a weaker correlation, suggesting that the observed radial gradients effectively reflect local variations of velocity dispersion. In our quest for a cause, instead of a correlation, we contrast $\sigma$ with local stellar mass, that appears less correlated with population properties. We conclude that the inherently higher uncertainty in M$_s$ may explain its lower correlation with respect to $\sigma$, but the extra uncertainty needed for $\sigma$ to have similar correlations as M$_s$ is rather high. Therefore we posit local velocity dispersion as the major driver of evolution, a result that should be reproduced by hydrodynamical models at the proper resolution.

Large-scale structure surveys measure the shape and position of millions of galaxies in order to constrain the cosmological model with high precision. The resulting large data volume poses a challenge for the analysis of the data, from the estimation of photometric redshifts to the calibration of shape measurements. We present GalSBI, a model for the galaxy population, to address these challenges. This phenomenological model is constrained by observational data using simulation-based inference (SBI). The $\texttt{galsbi}$ Python package provides an easy interface to generate catalogs of galaxies based on the GalSBI model, including their photometric properties, and to simulate realistic images of these galaxies using the $\texttt{UFig}$ package.

We examine several dark energy models with a time-varying equation of state parameter, $w(z)$, to determine what information can be derived by fitting the distance modulus in such models to a constant equation of state parameter, $w_*$. We derive $w_*$ as a function of the model parameters for the Chevallier-Polarski-Linder (CPL) parametrization, and for the Dutta-Scherrer approximation to hilltop quintessence models. We find that all of the models examined here can be well-described by a pivot-like redshift, $z_{pivot}$ at which the value of $w(z)$ in the model is equal to $w_*$. However, the exact value of $z_{pivot}$ is a model-dependent quantity; it varies from $z_{pivot} = 0.22-0.25$ for the CPL models to $z_{pivot} = 0.17-0.20$ for the hilltop quintessence models. Hence, for all of the models considered here, a constant-$w$ fit gives the value of $w$ for $z$ near 0.2. However, given the fairly wide variation in $z_{pivot}$ over even this restricted set of models, the information gained by fitting to a constant value of $w$ seems rather limited.

Context. Low-mass bodies, such as comets, asteroids, planetesimals, and free-floating planets, are continuously injected into the intra-cluster environment after expulsion from their host planetary systems. These can be modeled as massless particles (MLPs, hereafter). The dynamics of large populations of MLPs, however, has yet received little attention in literature. Aims. We investigate the dynamical evolution of MLP populations in star clusters, and characterize their kinematics and ejection rates. Methods. We present NBODY6++GPU-MASSLESS, a modified version of the N-body simulation code NBODY6++GPU, that allows fast integration of star clusters that contain large numbers of massless particles (MLPs). NBODY6++GPU-MASSLESS contains routines specifically directed at the dynamical evolution of low-mass bodies, such as planets. Results. Unlike stars, MLPs do not participate in the mass segregation process. Instead, MLPs mostly follow the gravitational potential of the star cluster, which gradually decreases over time due to stellar ejections and stellar evolution. The dynamical evolution of MLPs is primarily affected by the evolution of the core of the star cluster. This is most apparent in the outer regions for clusters with higher initial densities. High escape rates of MLPs are observed before the core-collapse, after which escape rates remain stable. Denser star clusters undergo a more intense core collapse, but this does not impact the dynamical evolution of MLPs. The speeds of escaping stars are similar to those of escaping MLPs, when disregarding the high-velocity ejections of neutron stars during the first 50 Myr.

A complete understanding of the initial conditions of high-mass star formation and what processes determine multiplicity require the study of the magnetic field (B-field) in young, massive cores. Using ALMA 250 GHz polarization (0.3" = 1000 au) and ALMA 220 GHz high-angular resolution observations (0.05" = 160 au), we have performed a full energy analysis including the B-field at core scales and have assessed what influences the multiplicity inside a massive core previously believed to be in the prestellar phase. With 31 Msun, the G11.92 MM2 core has a young CS outflow with a dynamical time scale of a few thousand years. At high-resolution, the MM2 core fragments into a binary system with a projected separation of 505 au and a binary mass ratio of 1.14. Using the DCF method with an ADF analysis, we estimate in this core a B-field strength of 6.2 mG and a mass-to-flux ratio of 18. The MM2 core is strongly subvirialized with a virial parameter of 0.064, including the B-field. The high mass-to-flux ratio and low virial parameter indicate that this massive core is very likely undergoing runaway collapse, which is in direct contradiction with the core-accretion model. The MM2 core is embedded in a filament that has a velocity gradient consistent with infall. In line with clump-fed scenarios, the core can grow in mass at a rate of 1.9--5.6 x 10^-4 Msun/yr. In spite of the B-field having only a minor contribution to the total energy budget at core scales, it likely plays a more important role at smaller scales by setting the binary properties. Considering energy ratios and a fragmentation criterion at the core scale, the binary could have been formed by core fragmentation. The binary properties (separation and mass ratio), however, are also consistent with radiation-magnetohydrodynamic simulations with super-Alfvenic, supersonic (or sonic) turbulence that form binaries by disk fragmentation.

Within the framework of General Relativity, it can be shown that gravitational waves are radiated with the merger of massive compact objects. Such gravitational wave signals are observed on Earth on various detectors, in particular, on Laser Interferometer Gravitational Wave Observatory (LIGO) and Virgo. During the operation of these detectors, many events have been detected. Those events are associated with the merger of massive compact objects, however, the nature of some merging objects has not yet been reliably established. This work considers non-topological solitons of dark matter -- Q-balls, as candidates for the role of massive compact objects. In this work one of the simplest models of Q-balls, the mechanism of their birth during a phase transition in the early Universe and the mechanism of their mass gaining during the evolution of the Universe, which is based on their mutual merger are considered. As a result, it is analyzed whether Q-balls of dark matter can be candidates for the role of massive compact objects.

We use hierarchical Bayesian modelling to calibrate a network of 32 all-sky faint DA white dwarf (DA WD) spectrophotometric standards ($16.5 < V < 19.5$) alongside the three CALSPEC standards, from 912 Å to 32 $\mu$m. The framework is the first of its kind to jointly infer photometric zeropoints and WD parameters ($\log g$, $T_{\text{eff}}$, $A_V$, $R_V$) by simultaneously modelling both photometric and spectroscopic data. We model panchromatic HST/WFC3 UVIS and IR fluxes, HST/STIS UV spectroscopy and ground-based optical spectroscopy to sub-percent precision. Photometric residuals for the sample are the lowest yet yielding $<0.004$ mag RMS on average from the UV to the NIR, achieved by jointly inferring time-dependent changes in system sensitivity and WFC3/IR count-rate nonlinearity. Our GPU-accelerated implementation enables efficient sampling via Hamiltonian Monte Carlo, critical for exploring the high-dimensional posterior space. The hierarchical nature of the model enables population analysis of intrinsic WD and dust parameters. Inferred SEDs from this model will be essential for calibrating the James Webb Space Telescope as well as next-generation surveys, including Vera Rubin Observatory's Legacy Survey of Space and Time, and the Nancy Grace Roman Space Telescope.

Most galaxies, including the Milky Way, host a supermassive black hole (SMBH) at the center. These SMBHs can be observed out to high redshifts (z>=6). However, we do not fully understand the mechanism through which these black holes form and grow at early times. The heavy (or direct collapse) seeding mechanism has emerged as a probable contender in which the core of an atomic cooling halo directly collapses into a dense stellar cluster that could host supermassive stars that proceed to form a BH seed of mass ~10^5 Msun. We use the Renaissance simulations to investigate the properties of 35 DCBH candidate host halos at $z = 15-24$ and compare them to non-candidate halos. We aim to understand what features differentiate halos capable of hosting a DCBH from the general halo population with the use of statistical analysis and machine learning methods. We examine 18 halo, central, and environmental properties. We find that DCBH candidacy is more dependent on a halo's core internal properties than on exterior factors and effects; our analysis selects density and radial mass influx as the most important features (outside of those used to establish candidacy). Our results concur with the recent suggestion that DCBH host halos neither need to lie within a "Goldilocks zone" nor have a significant amount of Lyman-Werner flux to suppress cooling. This paper presents insight to the dynamics possibly occurring in potential DCBH host halos and seeks to provide guidance to DCBH subgrid formation models.

We investigate the properties of cold gas at $10^4~\rm K$ around star-forming galaxies at $z~\sim~1$ using Mg II spectra through radiative transfer modeling. We utilize a comprehensive dataset of 624 galaxies from the MAGG and MUDF programs. We focus on Mg II emission from galaxies and their outskirts to explore the cold gas within galaxies and the circumgalactic medium (CGM). We model Mg II spectra for 167 individual galaxies and stacked data for different stellar mass bins. The Mg II spectrum and surface brightness vary significantly with stellar mass. In low-mass galaxies ($M_*/M_\odot<10^9$), Mg II emission is observed in both core ($R_{\rm p}<$ 10 kpc) and halo regions (10 kpc $<R_{\rm p}<$ 30 kpc), while in higher mass galaxies ($M_*/M_\odot>10^{10}$), strong core absorption and more extended halo emission are prominent. This indicates that more massive galaxies have more cold gas. Radiative transfer modeling allows us to investigate key parameters such as the Mg II column density $N_{\rm MgII}$ and the outflow velocity $v_{\rm exp}$. We identify a negative correlation between $N_{\rm MgII}$ and $v_{\rm exp}$. Since higher stellar mass galaxies exhibit a higher $N_{\rm MgII}$ and lower $v_{\rm exp}$, this suggests an abundance of slowly moving cold gas in massive galaxies. In addition, the fitting results of halo spectra indicate the presence of intrinsic Mg II absorption and strong anisotropy of the cold gas distribution around massive galaxies. This study is not only a proof-of-concept of modeling spatially varying Mg II spectra but also enhances our understanding of the CGM and provides insights into the mass-dependent properties of cold gas in and around galaxies.

The Galactic gamma-ray flux can be described as the sum of two components: the first is due to the emission from an ensemble of discrete sources, and the second is formed by the photons produced by cosmic rays propagating in interstellar space and interacting with gas or radiation fields. The source component is partially resolved as the contributions from individual sources, but a fraction is unresolved and appears as a diffuse flux. Both the unresolved source flux and the interstellar emission flux encode information of great significance for high energy astrophysics, and therefore the separation of these two contributions is very important. In this work we use the distributions in celestial coordinates of the objects contained in the catalogs obtained by the Extensive Air Showers telescopes HAWC and LHAASO to estimate the total luminosity of the Galactic gamma--ray sources and the contribution of unresolved sources to the diffuse gamma--ray flux. This analysis suggests that while the flux from unresolved sources is measurable and important, the dominant contribution to the diffuse flux over most of the celestial sphere is interstellar emission.

EL CVn-type systems represent a rare evolutionary stage in binary star evolution, providing ideal laboratories for investigating stable mass transfer processes and the formation of extremely low-mass white dwarfs (ELM WDs). The Transiting Exoplanet Survey Satellite (TESS) has delivered an extensive collection of high-precision time-domain photometric data, which is invaluable for studying EL CVn binaries. In this study, we identified 29 EL CVn systems from the TESS eclipsing binary catalogs (sectors 1-65), 11 of which are newly discovered. These systems consist of smaller, hotter pre-He white dwarfs and A/F main-sequence stars. The orbital periods of these binaries range from 0.64 to 2.5 days. Utilizing TESS light curves, Gaia distances, and multi-band photometric data (e.g., GALEX, 2MASS, WISE, SkyMapper), we modeled the light curves and spectral energy distributions to derive system parameters, including effective temperatures, masses, and radii. These systems were then compared with the white dwarf mass-period relation and the evolutionary tracks of ELM WDs. The comparison reveals that these binaries are consistent with the expected mass-period relation for white dwarfs and align well with the evolutionary tracks on the Teff-logg diagram for ELM WDs. This result suggests that these EL CVn systems likely formed through stable mass transfer processes. We provide a catalog of complete parameters for 29 EL CVn systems identified from the TESS survey. This catalog will serve as an essential resource for studying binary mass transfer, white dwarf formation, and pulsation phenomena in EL CVn-type systems.

We describe the software package $\texttt{ESpRESSO}$ - [E]xtragalactic [Sp]ectroscopic [R]oman [E]mulator and [S]imulator of [S]ynthetic [O]bjects, created to emulate the slitless spectroscopic observing modes of the Nancy Grace Roman Space Telescope (Roman) Wide Field Instrument (WFI). We combine archival Hubble Space Telescope (HST) imaging data of comparable spatial resolution with model spectral energy distributions to create a data-cube of flux density as a function of position and wavelength. This data-cube is used for simulating a nine detector grism observation, producing a crowded background scene which model field angle dependent optical distortions expected for the grism. We also demonstrate the ability to inject custom sources using the described tools and pipelines. In addition, we show that spectral features such as emission line pairs are unlikely to be mistaken as off order contaminating features and vice versa. Our result is a simulation suite of half of the eighteen detector array, with a realistic background scene and injected Ly$\alpha$ emitter (LAE) galaxies, realized at 25 position angles (PAs), 12 with analogous positive and negative dithers, Using an exposure time of 10ks per PA, the full PA set can be used as a mock deep Roman grism survey with high (synthetic) LAE completeness for developing future spectral data analysis tools.

The growing ``Hubble tension'' has prompted the need for precise measurements of cosmological distances. This paper demonstrates a purely geometric approach for determining the distance to extragalactic binaries through a joint analysis of spectroastrometry (SA), radial velocity (RV), and light curve (LC) observations. A parameterized model for the binary system is outlined, and simulated SA, RV, and LC data are computed to infer the probability distribution of model parameters based on the mock data. The impact of data quality and binary parameters on distance uncertainties is comprehensively analyzed, showcasing the method's potential for high-precision distance measurements. For a typical eclipsing binary in the Large Magellanic Cloud (LMC), the distance uncertainty is approximately 6% under reasonable observational conditions. Within a specific range of data quality and input parameters, the distance measurement precision of individual binary star systems is generally better than 10%. As a geometric method based on the simplest dynamics, it is independent of empirical calibration and the systematics caused by model selections can be tested using nearby binaries with known distances. By measuring multiple binary star systems or monitoring one binary system repeatedly, geometric distance measurements of nearby galaxies can be achieved, providing valuable insights into the Hubble tension and advancing our understanding of the universe's structure and evolution.

Blue Large-Amplitude Pulsators (BLAPs) represent a recently identified class of pulsating stars distinguished by their short pulsation periods (22-40 minutes) and asymmetric light curves. This study investigates the evolutionary channel of HD 133729, the first confirmed BLAP in a binary system. Through binary evolution simulations with MESA, we explored various mass ratios and initial orbital periods, finding that a mass ratio of q = 0.30 coupled with non-conservative mass transfer ($\rm \beta$ = 0.15) successfully reproduces the observational characteristics (including luminosity, surface gravity, and effective temperature) of the binary system. Our models not only match the observed pulsational properties but also predict significant helium and nitrogen enhancements on the surface of the main-sequence companion. The system is expected to eventually undergo a common envelope phase leading to a stellar merger. Our findings provide crucial insights into the formation mechanism and evolutionary fate of BLAPs with main-sequence companions, while also placing constraints on the elemental abundances of their binary companions.

Long-term evolution characteristics of the solar transition region have been unclear. In this study, daily images of the solar full disk derived from the observations by the Solar Dynamics Observatory/Atmospheric Imaging Assembly at 304 A wavelength from 2011 January 1 to 2022 December 31 are used to investigate long-term evolution of the solar transition region. It is found that long-term variation in the transition region of the full disk is in phase with the solar activity cycle, and thus the polar brightening should occur in the maximum epoch of the solar cycle. Long-term variation of the background transition region is found to be likely in anti-phase with the solar activity cycle at middle and low latitudes. The entire transition region, especially the active transition region is inferred to be mainly heated by the active-region magnetic fields and the ephemeral-region magnetic fields, while the quieter transition region is believed to be mainly heated by network magnetic fields. Long-term evolution characteristics of various types of the magnetic fields at the solar surface are highly consistent with these findings, and thus provide an explanation for them.

Radio observations provide a powerful tool to constrain the assembly of galaxies over cosmic time. Recent deep and wide radio continuum surveys have improved significantly our understanding on radio emission properties of AGNs and SFGs across $0 < z < 4$. This allows us to derive an empirical model of the radio continuum emission of galaxies based on their SFR and the probability of hosting an radio AGN. We make use of the Empirical Galaxy Generator (EGG) to generate a near-infrared-selected, flux-limited multi-wavelength catalog to mimic real observations. Then we assign radio continuum flux densities to galaxies based on their SFRs and the probability of hosting a radio-AGN of specific 1.4 GHz luminosity. We also apply special treatments to reproduce the clustering signal of radio this http URL empirical model successfully recovers the observed 1.4 GHz radio luminosity functions (RLFs) of both AGN and SFG populations, as well as the differential number counts at various radio bands. The uniqueness of this approach also allows us to directly link radio flux densities of galaxies to other properties, including redshifts, stellar masses, and magnitudes at various photometric bands. We find that roughly half of the radio continuum sources to be detected by SKA at $z \sim 4-6$ will be too faint to be detected in the optical survey ($r \sim 27.5$) carried out by Rubin observatory. Unlike previous studies which utilized RLFs to reproduce ERB, our work starts from a simulated galaxy catalog with realistic physical properties. It has the potential to simultaneously, and self-consistently reproduce physical properties of galaxies across a wide range of wavelengths, from optical, NIR, FIR to radio wavelengths. Our empirical model can shed light on the contribution of different galaxies to the extragalactic background light, and greatly facilitates designing future multiwavelength galaxy surveys.

We applied machine learning to the entire data history of ESO's High Accuracy Radial Velocity Planet Searcher (HARPS) instrument. Our primary goal was to recover the physical properties of the observed objects, with a secondary emphasis on simulating spectra. We systematically investigated the impact of various factors on the accuracy and fidelity of the results, including the use of simulated data, the effect of varying amounts of real training data, network architectures, and learning paradigms. Our approach integrates supervised and unsupervised learning techniques within autoencoder frameworks. Our methodology leverages an existing simulation model that utilizes a library of existing stellar spectra in which the emerging flux is computed from first principles rooted in physics and a HARPS instrument model to generate simulated spectra comparable to observational data. We trained standard and variational autoencoders on HARPS data to predict spectral parameters and generate spectra. Our models excel at predicting spectral parameters and compressing real spectra, and they achieved a mean prediction error of approximately 50 K for effective temperatures, making them relevant for most astrophysical applications. Furthermore, the models predict metallicity ([M/H]) and surface gravity (log g) with an accuracy of approximately 0.03 dex and 0.04 dex, respectively, underscoring their broad applicability in astrophysical research. The models' computational efficiency, with processing times of 779.6 ms on CPU and 3.97 ms on GPU, makes them valuable for high-throughput applications like massive spectroscopic surveys and large archival studies. By achieving accuracy comparable to classical methods with significantly reduced computation time, our methodology enhances the scope and efficiency of spectroscopic analysis.

This work focuses on two linear interaction models between dark matter and dark energy, which are proposed as key factors in explaining cosmic history, specifically the latetime accelerating expansion of the universe. Both models are constrained using a Markov chain Monte Carlo analysis (MCMC) using different sets of observational data. The analysis was composed using the Pantheon data set, consisting of 1048 points of SNIa distance moduli measurements from the Pantheon analysis and the Observed Hubble Parameter (OHD) data set using Baryon acoustic Oscillation (BAO), consisting of 57 data points using distance and expansion rate measurement. Both models showed promising results with the OHD data (BAO), with a interaction that results in a higher dark matter content of 56% and 44%, and a Hubble parameter of 65.7+-3km/ s/Mpc and 65.8+-3km/ s/Mpc for the interaction dependent on dark matter and dark energy respectively. The pantheon data set however predicted a reverse interaction for both models which does not follow initial assumptions that were made. The pantheon data measured a dark matter content of 18% and 20% with a Hubble parameter of 72.1 +- 0.003km/ s/Mpc and 72.3 +- 0.004km /s/Mpc. The constrained results are used to revisit the coincidence problem and other problems in standard cosmology. The analysis provided a discrepancy between the different data sets with one having a large error margin.

In the era of Gaia, the accurate determination of stellar ages is transforming Galactic archaeology. We demonstrate the feasibility of inferring stellar ages from Gaia's RVS spectra and the BP/RP (XP) spectrophotometric data, specifically for red giant branch and high-mass red clump stars. We successfully train two machine learning models, dubbed SIDRA: Stellar age Inference Derived from Gaia spectRA to predict the age. The SIDRA-RVS model uses the RVS spectra and SIDRA-XP the stellar parameters obtained from the XP spectra by Fallows and Sanders 2024. Both models use BINGO, an APOGEE-derived stellar age from Ciuca et al. 2021 as the training data. SIDRA-RVS estimates ages of stars whose age is around $\tau_\mathrm{BINGO}=10$ Gyr with a standard deviation of residuals of $\sim$ 0.12 dex in the unseen test dataset, while SIDRA-XP achieves higher precision with residuals $\sim$ 0.064 dex for stars around $\tau_\mathrm{BINGO}=10$ Gyr. Since SIDRA-XP outperforms SIDRA-RVS, we apply SIDRA-XP to analyse the ages for 2,218,154 stars. This allowed us to map the chronological and chemical properties of Galactic disc stars, revealing distinct features such as the Gaia-Sausage-Enceladus merger and a potential gas-rich interaction event linked to the first infall of the Sagittarius dwarf galaxy. This study demonstrates that machine learning techniques applied to Gaia's spectra can provide valuable age information, particularly for giant stars, thereby enhancing our understanding of the Milky Way's formation and evolution.

Holographic dark energy (HDE), which arises from a theoretical attempt of applying the holographic principle (HP) to the dark energy (DE) problem, has attracted significant attention over the past two decades. We perform a most comprehensive numerical study on HDE models that can be classified into four categories: 1) HDE models with other characteristic length scale, 2) HDE models with extended Hubble scale, 3) HDE models with dark sector interaction, 4) HDE models with modified black hole entropy. For theoretical models, we select seven representative models, including the original HDE (OHDE) model, Ricci HDE (RDE) model, generalized Ricci HDE (GRDE) model, interacting HDE (IHDE1 and IHDE2) models, Tsallis HDE (THDE) model, and Barrow HDE (BHDE) model. For cosmological data, we use the Baryon Acoustic Oscillation (BAO) data from the Dark Energy Spectroscopic Instrument (DESI) 2024 measurements, the Cosmic Microwave Background (CMB) distance priors data from the Planck 2018, and the type Ia supernovae (SN) data from the PantheonPlus compilation. Using $\chi^2$ statistic and Bayesian evidence, we compare these HDE models with current observational data. It is found that: 1) The $\Lambda$CDM remains the most competitive model, while the RDE model is ruled out. 2) HDE models with dark sector interaction perform the worst across the four categories, indicating that the interaction term is not favored under the framework of HDE. 3) The other three categories show comparable performance. The OHDE model performs better in the BAO+CMB dataset, and the HDE models with modified black hole entropy perform better in the BAO+CMB+SN dataset. 4) HDE models with the future event horizon exhibit significant discrepancies in parameter space across datasets. The BAO+CMB dataset favors a phantom-like HDE, whereas the BAO+CMB+SN leads to an equation of state (EoS) much closer to the cosmological constant.

Type Ibn/Icn supernovae (SNe Ibn/Icn), which are characterized by narrow helium or carbon lines originated in hydrogen-poor dense circumstellar medium (CSM), provide new insights into the final evolution of massive stars. While SNe Ibn/Icn are expected to emit strong X-rays through the strong SN-CSM interaction, the X-ray emission modeling effort has been limited so far. In the present study, we provide broad-band X-ray light curve (LC) predictions for SNe Ibn/Icn. We find that the soft X-ray LC provides information about the CSM compositions, while the hard X-ray LC is a robust measure of the CSM density, the explosion energy, and the ejecta mass. In addition, considering the evolution of the ionization state in the unshocked CSM, a bright soft X-ray is expected in the first few days since the explosion, which encourages rapid X-ray follow-up observations as a tool to study the nature of SNe Ibn/Icn. Applying our model to the soft X-ray LCs of SNe Ibn 2006jc and 2022ablq, we derive that the CSM potentially contains a larger fraction of carbon and oxygen for SN 2006jc than 2022ablq, highlighting the power of the soft X-ray modeling to address the nature of the CSM. We also discuss detectability and observational strategy, with which the currently operating telescopes such as NuSTAR and Swift can offer an irreplaceable opportunity to explore the nature of these enigmatic rapid transients and their still-unclarified progenitor channel(s).

Many of the blazars observed by Fermi actually have the peak of their time-averaged gamma-ray emission outside the $\sim$ GeV Fermi energy range, at $\sim$ MeV energies. The detailed shape of the emission spectrum around the $\sim$ MeV peak places important constraints on acceleration and radiation mechanisms in the blazar jet and may not be the simple broken power law obtained by extrapolating from the observed X-ray and GeV gamma-ray spectra. In particular, state-of-the-art simulations of particle acceleration by shocks show that a significant fraction (possibly up to $\approx 90\%$) of the available energy may go into bulk, quasi-thermal heating of the plasma crossing the shock rather than producing a non-thermal power law tail. Other ``gentler" but possibly more pervasive acceleration mechanisms such as shear acceleration at the jet boundary may result in a further build-up of the low-energy ($\gamma \lesssim 10^{2}$) electron/positron population in the jet. As already discussed for the case of gamma-ray bursts, the presence of a low-energy, Maxwellian-like ``bump'' in the jet particle energy distribution can strongly affect the spectrum of the emitted radiation, e.g., producing an excess over the emission expected from a power-law extrapolation of a blazar's GeV-TeV spectrum. We explore the potential detectability of the spectral component ascribable to a hot, quasi-thermal population of electrons in the high-energy emission of flat-spectrum radio quasars (FSRQ). We show that for typical FSRQ physical parameters, the expected spectral signature is located at $\sim$ MeV energies. For the brightest Fermi FSRQ sources, the presence of such a component will be constrained by the upcoming MeV Compton Spectrometer and Imager (COSI) satellite.

Brown dwarfs are the bridge between low-mass stars and giant planets. One way of shedding light on their dominant formation mechanism is to study them at the earliest stages of their evolution, when they are deeply embedded in their parental clouds. Several works have identified pre- and proto-brown dwarfs candidates using different observational approaches. The aim of this work is to create a database with all the objects classified as very young substellar candidates in the litearature in order to study them in an homogeneous way. We have gathered all the information about very young substellar candidates available in the literature until 2020. We have retrieved their published photometry from the optical to the centimeter regime, and we have written our own codes to derive their bolometric temperatures and luminosities, and their internal luminosities. We have also populated the database with other parameters extracted from the literature, like e.g. the envelope masses, their detection in some molecular species, and presence of outflows. The result of our search is the SUCANES database, containing 174 objects classified as potential very young substellar candidates in the literature. We present an analysis of the main properties of the retrieved objects. Since we have updated the distances to several star forming regions, this has allowed us to reject some candidates based on their internal luminosities. We have also discussed the derived physical parameters and envelope masses for the best substellar candidates isolated in SUCANES. As an example of a scientific exploitation of this database, we present a feasibility study for the detection of radiojets with upcoming facilities: the ngVLA and the SKA interferometers. The SUCANES database is accessible through a Graphical User Interface and it is open to any potential user.

The young active flare star AU~Mic is the planet host star with the highest flare rate from TESS data. Therefore, it represents an ideal target for dedicated ground-based monitoring campaigns with the aim to characterize its numerous flares spectroscopically. We performed such spectroscopic monitoring with the ESO1.52m telescope of the PLATOSpec consortium. In more than 190 hours of observations, we find 24 flares suitable for detailed analysis. We compute their parameters (duration, peak flux, energy) in eight chromospheric lines (H$\alpha$, H$\beta$, H$\gamma$, H$\delta$, Na I D1&D2, He I D3, He I 6678) and investigate their relationships. Furthermore, we obtained simultaneous photometric observations and low-resolution spectroscopy for part of the spectroscopic runs. We detect one flare in the g'-band photometry which is associated with a spectroscopic flare. Additionally, an extreme flare event occurred on 2023-09-16 of which only a time around its possible peak was observed, during which chromospheric line fluxes were raised by up to a factor of three compared to the following night. The estimated energy of this event is around $10^{33}$ erg in H$\alpha$ alone, i.e. a rare chromospheric line superflare.

Stasis is a unique cosmological phenomenon in which the abundances of different energy components in the universe (such as matter, radiation, and vacuum energy) each remain fixed even though they scale differently under cosmological expansion. Moreover, extended epochs exhibiting stasis are generally cosmological attractors in many BSM settings and thus arise naturally and without fine-tuning. To date, stasis has been found within a number of very different BSM cosmologies. In some cases, stasis emerges from theories that contain large towers of decaying states (such as theories in extra dimensions or string theory). By contrast, in other cases, no towers of states are needed, and stasis instead emerges due to thermal effects involving particle annihilation rather than decay. In this paper, we study the dynamics of the energy flows in all of these theories during stasis, and find that these theories all share a common energy-flow structure which in some sense lies between particle decay and particle annihilation. This structure has been hidden until now but ultimately lies at the root of the stasis phenomenon, with all of the previous stases appearing as different manifestations of this common underlying structure. This insight not only allows us to understand the emergence of stasis in each of these different scenarios, but also provides an important guide for the potential future discovery of stasis in additional cosmological systems.

Sun-like stars are well represented in the solar neighbourhood but are currently under-utilised, with many studies of chemical and kinematic evolution focusing on red giants (which can be observed further away) or turn-off stars (which have well measured ages). Recent surveys (e.g. GALAH) provide spectra for large numbers of nearby Sun-like stars, which provides an opportunity to apply our newly developed method for measuring metallicities, temperatures, and surface gravities - the EPIC algorithm - which yields improved ages via isochrone fitting. We test this on moving groups, by applying it to the large GALAH DR3 sample. This defines a sample of 72,288 solar analogue targets for which the stellar parameter measurements are most precise and reliable. These stars are used to estimate, and test the accuracy and precision of, age measurements derived with the SAMD isochrone fitting algorithm. Using these ages, we recover the age-metallicity relationships for nearby (<= 1 kpc) moving groups, traced by solar analogues, and analyse them with respect to the stellar kinematics. In particular, we found that the age-metallicity relationships of all moving groups follows a particular trend of young (age < 6 Gyr) stars having constant metallicity and older (age >= 6 Gyr) stars decreasing in metallicity with increasing age. The Hercules stream carries the highest fraction of metal-rich young stars (~ 0.1 dex) in our sample, which is consistent with a migrating population of stars from the inner Galaxy, and we discuss the possible causes of this migration in the context of our results.

We present a comprehensive joint analysis of two distinct methodologies for measuring the mass of galaxy clusters: hydrostatic measurements and caustic techniques. We show that by including cluster-specific assumptions obtained from hydrostatic measurements in the caustic method, the potential mass bias between these approaches can be significantly reduced. Applying this approach to two well-observed massive galaxy clusters A2029 and A2142. We find no discernible mass bias, affirming the method's validity. We then extend the analysis to modified gravity models and draw a similar conclusion when applying our approach. Specifically, our implementation allows us to investigate Chameleon and Vainshtein screening mechanisms, tightening the posteriors and enhancing our understanding of these modified gravity scenarios.

The chemical abundances of elements such as barium and the lanthanides are essential to understand the nucleosynthesis of heavy elements in the early Universe as well as the contribution of different neutron capture processes (for example slow versus rapid) at different epochs. The Chemical Evolution of R-process Elements in Stars (CERES) project aims to provide a homogeneous analysis of a sample of metal-poor stars ( [Fe/H]\<-1.5) to improve our understanding of the nucleosynthesis of neutron capture elements, in particular the r-process elements, in the early Galaxy. Our data consist of a sample of high resolution and high signal-to-noise ratio UVES spectra. The chemical abundances were derived through spectrum synthesis, using the same model atmospheres and stellar parameters as derived in the first paper of the CERES series. We measured chemical abundances or upper limits of seven heavy neutron capture elements (Ba, La, Ce, Pr, Nd, Sm, and Eu) for a sample of 52 metal-poor giant stars. We estimated through the mean shift clustering algorithm that at Ba/H =-2.4 and Fe/H =-2.4 a variation in the trend of X/Ba with X=La,Nd,Sm,Eu, versus Ba/H occurs. This result suggests that, for Ba/H $\<$$-2.4$, Ba nucleosynthesis in the Milky Way halo is primarily due to the $r$-process, while for Ba/H \<-2.4 the effect of the s-process contribution begins to be visible. In our sample, stars with Ba/Eu compatible with a Solar System pure r-process value (hereafter, r-pure) do not show any particular trend compared to other stars, suggesting r-pure stars may form in similar environments to stars with less pure r-process enrichments. Homogeneous investigations of high resolution and signal-to-noise ratio spectra are crucial for studying the heavy elements formation, as they provide abundances that can be used to test nucleosynthesis models as well as Galactic chemical evolution models.

Recent research is revealing data-sonification as a promising complementary approach to vision, benefiting both data perception and interpretation. We present herakoi, a novel open-source software that uses machine learning to allow real-time image sonification, with a focus on astronomical data. By tracking hand movements via a webcam and mapping them to image coordinates, herakoi translates visual properties into sound, enabling users to "hear" images. Its swift responsiveness allows users to access information in astronomical images with short training, demonstrating high reliability and effectiveness. The software has shown promise in educational and outreach settings, making complex astronomical concepts more engaging and accessible to diverse audiences, including blind and visually impaired individuals. We also discuss future developments, such as the integration of large language and vision models to create a more interactive experience in interpreting astronomical data.

A simple orbit classification constraint extension to stellar dynamical modeling using Schwarzschild's method is demonstrated. The classification scheme used is the existing `orbit circularity' scheme (lambda_z) where orbits are split into four groups - hot, warm, cold and counter rotating orbits. Other schemes which can be related to the orbit weights are expected to be viable as well. The results show that the classification constraint works well in modeling. However, given that orbits in external galaxies are not observable, it is not clear how the orbit classification for any particular galaxy may be determined. Perhaps range constraints for different types of galaxies determined from cosmological simulations may offer a way forward.

We demonstrate a new methodology to model Roche lobe overflow (RLO) systems to unprecedented resolution simultaneously across the envelope, donor wind, tidal stream, and accretion disk regimes without reliance upon previously-universal symmetry, mass flux, and angular momentum flux assumptions. We have applied this method to the semidetached high-mass X-ray binary (HMXB) M33 X-7 in order to provide a direct comparison to recent observations of an RLO candidate system at two overflow states of overfilling factors f = 1.01 and f = 1.1. We found extreme overflow ( f = 1.1) to exhibit entirely conservative unstable mass transfer (MT), with tidal stream density and deflected angle comparable to predictions. The f = 1.01 case differed in stream geometry, accretion disk size, and efficiency, demonstrating non-conservative stable MT through a ballistic uniform-width stream. The non-conservative and stable nature of the f = 1.01 case MT also suggests that existing assumptions of semi-detached binaries undergoing RLO may mischaracterize the parameter space of stability for the L1 flow. We also conducted a piecewise evolution of M33 X-7 across nearly the entirety of RLO phase from onset to runaway unstable MT. We present the first model of the efficiency of MT and its associated angular momentum across overfilling factor parameter space. We also present novel relations for binary separation, mass ratio, L1 mass transfer rate, and Roche timescale as they vary with respect to the overfilling factor. These provide constraints on the threshold for the onset of unstable MT which ultimately led in our system to exponentially faster MT evolution. Collectively these parameter constraints, relations, and explorations probe RLO dynamics in HMXBs and their role and distribution as progenitors of binary black holes and common envelopes.

The solar corona is highly structured by bunches of magnetic field lines forming either loops, or twisted flux ropes representing prominences/filaments, or very dynamic structures such as jets. The aim of this paper is to understand the interaction between filament channels and jets. We use high-resolution H$\alpha$ spectra obtained by the ground-based Telescope Heliographique pour lEtude du Magnetisme et des Instabilites Solaires (THEMIS) in Canary Islands, and data from Helioseismic Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). In this paper we present a multi-wavelength study of the interaction of filaments and jets. They both consist of cool plasma embedded in magnetic structures. A jet is particularly well studied in all the AIA channels with a flow reaching 100-180 km s$^{-1}$. Its origin is linked to cancelling flux at the edge of the active region. Large Dopplershifts in H$\alpha$ are derived in a typical area for a short time (order of min). They correspond to flows around 140 km s$^{-1}$. In conclusion we conjecture that these flows correspond to some interchange of magnetic field lines between the filament channel and the jets leading to cool plasmoid ejections or reconnection jets perpendicularly to the jet trajectory.

We present high resolution images of the radio source 3C 84 at 43 GHz, from 121 observations conducted by the BEAM-ME monitoring program between 2010 and 2023. Imaging was performed using the recent forward modeling imaging method eht-imaging, which achieved a resolution of 80 $\mu$as, a factor of $\sim$2-3 better than traditional imaging methods such as CLEAN. The sequence of images depicts the growth and expansion of the parsec-scale relativistic jet in 3C 84, clearly resolving a complex internal structure, showing bending in the jet, and changes in its launching direction and expansion speed. We report measurements of the expansion speed in time, which show that the jet undergoes three regimes, marked by the beginning and ending of a hot spot frustration phase. The images' high resolution allows us also to measure the projected launching direction as a function of time, finding an irregular variation pattern. Our results confirm previous studies of the morphological transition underwent by 3C 84 and provide quantitative measurements of the jet's kinematic properties over a decade time-scale.

Extended main-sequence stars that are dim in the ultraviolet passbands of Hubble Space Telescope (UV-dim stars) are found in several young and intermediate-age Magellanic Cloud star clusters. The obscuring of the dust in the discs of stars expelled due to fast rotation have been suggested to be responsible for the appearance of UV-dim stars, and play an important role in the formation of extended main-sequences. In this paper, we report a population of A- and F-type stars who show H{\alpha} emission features in their spectra in a young (~ 340 Myr-old) Galactic neighboring star cluster NGC 3532. By fitting the observed absorption profiles, we found that most H{\alpha} emitters are fast rotating stars, indicating that they form decretion discs by fast rotation like Be stars. As A- and F-type stars dominate the extended main-sequence turn-off regions of intermediate-age clusters, their appearance provides observational evidence to support the dust extinction scenario for these clusters, and might be the counterparts of UV-dim stars that are detected in remote Magellanic Cloud star clusters like NGC 1783.

Complex organic molecules serve as indicators of molecular diversity. Their detection on comets, planets, and moons has prompted inquiries into their origins, particularly the conditions conducive to their formation. One hypothesis suggests that the UV irradiation of icy grains in the protosolar nebula generates significant molecular complexity, a hypothesis supported by experiments on methanol ice irradiation. We investigated the irradiation of methanol ice particles as they migrate through the protosolar nebula. Our objective is to ascertain whether the encountered conditions facilitate the formation of complex organics molecules, and we leverage experimental data in our analysis. We developed a two-dimensional model that describes the transport of pebbles during the evolution of the protosolar nebula, employing a Lagrangian scheme. This model computes the interstellar UV flux received by the particles along their paths, which we compared with experimental values. On average, particles ranging from 1 to 100 micrometers in size, released at a local temperature of 20 K, undergo adequate irradiation to attain the same molecular diversity as methanol ice during the experiments within timescales of 25 kyr of protosolar nebula evolution. In contrast, 1 cm sized particles require 911 kyr of irradiation to reach similar molecular diversity, making comparable molecular complexity unlikely. Similarly, particles ranging from 1 to 100 micrometers in size, released at a local temperature of 80 K, receive sufficient irradiation after 141 and 359 kyr. The particles readily receive the irradiation dose necessary to generate the molecular diversity observed in the experiments within the outer regions of the disk. Our model, combined with future irradiation experiments, can provide additional insights into the specific regions where the building blocks of planets form.

We carry out an extensive light curve comparison of BL Her stars using observations from Gaia DR3 and stellar pulsation models computed using MESA-RSP with the goal to obtain the best-matched modeled-observed pairs for BL Her stars in the LMC. We use the Fourier decomposition technique to analyse the light curves in the G band obtained from Gaia DR3 and from MESA-RSP and use a robust light curve fitting approach to score the modeled-observed pairs with respect to their pulsation periods and over their Fourier parameter space. We obtain the best-fit models for 48 BL Her stars in the LMC and thereby provide the stellar parameter estimates of these stars, 30 of which are labelled as the gold sample with superior light curve fits. We find a relatively flat distribution of stellar masses between 0.5-0.65 Msolar for the gold sample of modeled-observed pairs. An interesting result is that the majority of the best-matched models in the gold sample are computed using the convection parameter sets without radiative cooling. The period-Wesenheit relation for the best-matched gold sample of 30 BL Her models exhibits a slope of $-2.805 \pm 0.164$ while the corresponding period-radius relation exhibits a slope of $0.565 \pm 0.035$, both in good agreement with the empirical PW and PR slopes from BL Her stars in the LMC, respectively. We also used the Wesenheit magnitudes of the 30 best-matched modeled-observed pairs to estimate a distance modulus of $\mu_{\rm LMC} = 18.582 \pm 0.067$ to the LMC, which lies within the bounds of previous literature values. We also discuss the degeneracy in the stellar parameters of the BL Her models that result in similar pulsation periods and light curve structure, and highlight that caution must be exercised while using the stellar parameter estimates.

Primordial black holes (PBHs) are a major candidate for dark matter and they have been extensively constrained across most mass ranges. However, PBHs in the mass range of $10^{17}-10^{21}$ g remain a viable explanation for all dark matter. In this work, we use observational data from the Hard X-ray Modulation Telescope (Insight-HXMT) to refine constraints on PBHs within the mass range of $10^{16}-10^{18}$ g. Our analysis explores three scenarios: directly using observational data, incorporating the astrophysical background model (ABM), and employing the power-law spectrum with an exponential cutoff. Additionally, we also account for photon flux from positron annihilation due to Hawking radiation in our calculations. Our findings indicate that directly using observational data significantly tightens constraints on PBHs with masses above $10^{17}$ g, owing to Insight-HXMT's exceptional sensitivity to hard X-rays. Incorporating the ABM further enhances the constraints by approximately 0.8 orders of magnitude. The exclusion limit for PBHs as dark matter extends to $8\times 10^{17}$ g, nearly doubling the current threshold. Moreover, extrapolating the energy limit with a power-law model improves constraints by approximately one order of magnitude compared to the ABM scenario.

We present the first widefield extragalactic continuum catalogue with the MeerKAT S-band (2.5 GHz), of the radio-selected DEEP2 field. The combined image over the S1 (1.96 - 2.84 GHz) and S4 (2.62 - 3.50 GHz) sub-bands has an angular resolution of 6.8''$\times$3.6'' (4.0''$\times$2.4'') at a robust weighting of $R = 0.3$ ($R=-0.5$) and a sensitivity of 4.7 (7.5) $\mu$Jy beam$^{-1}$ with an on-source integration time of 70 minutes and a minimum of 52 of the 64 antennas, for respective observations. We present the differential source counts for this field, as well as a morphological comparison of resolved sources between S-band and archival MeerKAT L-band images. We find consistent source counts with the literature and provide spectral indices fitted over a combined frequency range of 1.8 GHz. These observations provide an important first demonstration of the capabilities of MeerKAT S-band imaging with relatively short integration times, as well as a comparison with existing S-band surveys, highlighting the rich scientific potential with future MeerKAT S-band surveys.

We present optical monitoring of the neutron star low-mass X-ray binary Swift J1858.6-0814 during its 2018-2020 outburst and subsequent quiescence. We find that there was strong optical variability present throughout the entire outburst period covered by our monitoring, while the average flux remained steady. The optical spectral energy distribution is blue on most dates, consistent with emission from an accretion disc, interspersed by occasional red flares, likely due to optically thin synchrotron emission. We find that the fractional rms variability has comparable amplitudes in the radio and optical bands. This implies that the long-term variability is likely to be due to accretion changes, seen at optical wavelengths, that propagate into the jet, seen at radio frequencies. We find that the optical flux varies asymmetrically about the orbital period peaking at phase ~0.7, with a modulation amplitude that is the same across all optical wavebands suggesting that reprocessing off of the disc, companion star and ablated material is driving the phase dependence. The evidence of ablation found in X-ray binaries is vital in understanding the long term evolution of neutron star X-ray binaries and how they evolve into (potentially isolated) millisecond pulsars.

Theoretical predictions from a modified theory of gravity with a nonminimal coupling between matter and curvature are compared to data from recent cosmological surveys. We use type Ia supernovae data from the Pantheon+ sample and the recent 5-year Dark Energy Survey (DES) data release along with baryon acoustic oscillation measurements from the Dark Energy Spectroscopic Instrument (DESI) and extended Baryon Oscillation Spectroscopic Survey (eBOSS) to constrain the modified model's parameters and to compare its fit quality to the Flat-$\Lambda$CDM model. We find moderate to strong evidence for a preference of the nonminimally coupled theory over the current standard model for all dataset combinations. Although the modified model is shown to be capable of matching early-time observations from the cosmic microwave background and late-time supernovae data, we find that there is still some incoherence with respect to the conclusions drawn from baryon acoustic oscillation observations.

We present an analysis of three near-infrared (NIR; 1.0-2.4 $\mu$m) spectra of the SN 2003fg-like/"super-Chandrasekhar" type Ia supernovae (SNe Ia) SN 2009dc, SN 2020hvf, and SN 2022pul at respective phases +372, +296, and +294~d relative to the epoch of $B$-band maximum. We find that all objects in our sample have asymmetric, or "tilted", [Fe~II] 1.257 and 1.644 $\mu$m profiles. We quantify the asymmetry of these features using five methods: velocity at peak flux, profile tilts, residual testing, velocity fitting, and comparison to deflagration-detonation transition models. Our results demonstrate that, while the profiles of the [Fe II] 1.257 and 1.644 $\mu$m features are widely varied between 2003fg-likes, these features are correlated in shape within the same SN. This implies that line blending is most likely not the dominant cause of the asymmetries inferred from these profiles. Instead, it is more plausible that 2003fg-like SNe have aspherical chemical distributions in their inner regions. These distributions may come from aspherical progenitor systems, such as double white dwarf mergers, or off-center delayed-detonation explosions of Chandrasekhar-mass Carbon-Oxygen white dwarfs. Additional late-phase NIR observation of 2003fg-like SNe and detailed 3-D NLTE modeling of these two explosion scenarios are encouraged.

This work presents the semi-analytical light curve modelling results of 11 stripped-envelope SNe (SESNe), where millisecond magnetars potentially drive their light curves. The light-curve modelling is performed utilizing the $\chi^2$-minimisation code $\texttt{MINIM}$ considering millisecond magnetar as a central engine powering source. The magnetar model well regenerates the bolometric light curves of all the SESNe in the sample and constrains numerous physical parameters, including magnetar's initial spin period ($P_\textrm{i}$) and magnetic field ($B$), explosion energy of supernova ($E_\textrm{exp}$), progenitor radius ($R_\textrm{p}$), etc. Within the sample, the superluminous SNe 2010kd and 2020ank exhibit the lowest $B$ and $P_\textrm{i}$ values, while the relativistic Ic broad-line SN 2012ap shows the highest values for both parameters. The explosion energy for all SESNe in the sample (except SN 2019cad), exceeding $\gtrsim$2 $\times$ 10$^{51}$ erg, indicates there is a possibility of a jittering jet explosion mechanism driving these events. Additionally, a correlation analysis identifies linear dependencies among parameters derived from light curve analysis, revealing positive correlations between rise and decay times, $P_\textrm{i}$ and $B$, $P_\textrm{i}$ and $R_\textrm{p}$, and $E_\textrm{exp}$ and $R_\textrm{p}$, as well as strong anti-correlations of $P_\textrm{i}$ and $B$ with the peak luminosity. Principal Component Analysis is also applied to key parameters to reduce dimensionality, allowing a clearer visualization of SESNe distribution in a lower-dimensional space. This approach highlights the diversity in SESNe characteristics, underscoring unique physical properties and behaviour across different events in the sample. This study motivates further study on a more extended sample of SESNe to look for millisecond magnetars as their powering source.

This paper describes applying manifold learning, the novel technique of dimensionality reduction, to the images of the Galaxy Zoo DECaLs database with the purpose of building an unsupervised learning model for galaxy morphological classification. The manifold learning method assumes that data points can be projected from a manifold in high-dimensional space to a lower-dimensional Euclidean one while maintaining proximity between the points. In our case, data points are photos of galaxies from the Galaxy Zoo DECaLs database, which consists of more than 300,000 human-labeled galaxies of different morphological types. The dimensionality of such data points is equal to the number of pixels in a photo, so dimensionality reduction becomes a handy idea to help one with the successive clusterization of the data. We perform it using Locally Linear Embedding, a manifold learning algorithm, designed to deal with complex high-dimensional manifolds where the data points are originally located. After the dimensionality reduction, we perform the classification procedure on the dataset. In particular, we train our model to distinguish between round and cigar-shaped elliptical galaxies, smooth and featured spiral galaxies, and galaxies with and without disks viewed edge-on. In each of these cases, the number of classes is pre-determined. The last step in our pipeline is k-means clustering by silhouette or elbow method in lower-dimensional space. In the final case of unsupervised classification of the whole dataset, we determine that the optimal number of morphological classes of galaxies coincides with the number of classes defined by human astronomers, further confirming the feasibility and efficiency of manifold learning for this task.

Optically dark dusty star-forming galaxies (DSFGs) play an essential role in massive galaxy formation at early cosmic time, however their nature remains elusive. Here we present a detailed case study of all the baryonic components of a $z=4.821$ DSFG, XS55. Selected from the ultra-deep COSMOS-XS 3GHz map with a red SCUBA-2 450$\mu$m/850$\mu$m colour, XS55 was followed up with ALMA 3mm line scans and spectroscopically confirmed to be at $z=4.821$ via detections of the CO(5-4) and [CI](1-0) lines. JWST/NIRCam imaging reveals that XS55 is a F150W-dropout with red F277W/F444W colour, and a complex morphology: a compact central component embedded in an extended structure with a likely companion. XS55 is tentatively detected in X-rays with both Chandra and XMM-Newton, suggesting an active galactic nucleus (AGN) nature. By fitting a panchromatic SED spanning NIR to radio wavelengths, we revealed that XS55 is a massive main-sequence galaxy with a stellar mass of $M_\ast=(5\pm1)\times10^{10}\,{\rm M_\odot}$ and a star formation rate of ${\rm SFR}=540\pm177~{\rm M_\odot\,yr^{-1}}$. The dust of XS55 is optically thick in the far infrared (FIR) with a surprisingly cold dust temperature of $T_{\rm dust}=33\pm2\,{\rm K}$, making XS55 one of the coldest DSFGs at $z>4$ known to date. This work unveils the nature of a radio-selected F150W-dropout, suggesting the existence of a population of DSFGs hosting active black holes embedded in optically thick dust.

The magnetic cycle on the Sun consists of two consecutive 11-yr sunspot cycles and exhibits a polarity reversal around sunspot maximum. Although solar dynamo theories have progressively become more sophisticated, the details as to how the dynamo sustains magnetic fields are still subject of research. Observing the magnetic fields of Sun-like stars are useful to contextualise the solar dynamo. The BCool survey studies the evolution of surface magnetic fields to understand how dynamo-generated processes are influenced by key ingredients, like mass and rotation. Here, we focus on six Sun-like stars with mass between 1.02 and 1.06 MSun and with 3.5-21 d rotation period. We analysed high-resolution spectropolarimetric data collected with ESPaDOnS, Narval and Neo-Narval. We measured the longitudinal magnetic field from least-squares deconvolution line profiles and inspected its long-term behaviour with a Lomb-Scargle periodogram and a Gaussian process. We applied Zeeman-Doppler imaging to reconstruct the large-scale magnetic field geometry at the stellar surface for different epochs. Two stars, namely HD 9986 and HD 56124 (Prot ~ 20 d) exhibit cyclic variability with polarity reversals of the radial or toroidal field component on time scales of 5 to 6 yr. HD 73350 (Prot = 12 d) has one polarity reversal of the toroidal component and HD 76151 (Prot=17 d) may have short-term evolution (2.5 yr) modulated by the long-term (16 yr) chromospheric cycle. HD 166435 and HD 175726 (Prot =3-5 d), manifest complex magnetic fields without cyclic evolution. Our findings indicate the strong dependence of the magnetic cycles nature with stellar rotation period. For the stars with an identified cyclic evolution, the polarity reversal time scale seems to decrease with decreasing rotation period or Rossby number. These results represent important observational constraints for dynamo models of solar-like stars.

Neutron Stars (NSs), among the densest objects in the Universe, are exceptional laboratories for investigating Dark Matter (DM) properties. Recent theoretical and observational developments have heightened interest in exploring the impact of DM on NS structure, giving rise to the concept of Dark Matter Admixed Neutron Stars (DANSs). This review examines how NSs can accumulate DM over time, potentially altering their fundamental properties. We explore leading models describing DM behavior within NSs, focusing on the effects of both bosonic and fermionic candidates on key features such as mass, radius, and tidal deformability. Additionally, we review how DM can modify the cooling and heating processes, trigger the formation of a black hole, and impact Gravitational Waves (GWs) emissions from binary systems. By synthesizing recent research, this work highlights how DANSs might produce observable signatures, offering new opportunities to probe DM properties through astrophysical phenomena.

This study focuses on a radial alignment between Parker Solar Probe (PSP) and Solar Orbiter (SolO) on the 29$^{\text{th}}$ of April 2021 (during a solar minimum), when the two spacecraft were respectively located at $\sim 0.075$ and $\sim 0.9$~au from the Sun. A previous study of this alignment allowed the identification of the same density enhancement (with a time scale of $\sim$1.5~h), and substructures ($\sim$20-30~min timescale), passing first by PSP, and then SolO after a $\sim 138$~h propagation time in the inner heliosphere. We show here that this structure belongs to the large scale heliospheric magnetic sector boundary. In this region, the density is dominated by radial gradients, whereas the magnetic field reversal is consistent with longitudinal gradients in the Carrington reference frame. We estimate the density structure radial size to remain of the order L$_R \sim 10^6$~km, while its longitudinal and latitudinal sizes, are estimated to expand from L$_{\varphi, \theta} \sim 10^4$-$10^5$~km in the high solar corona, to L$_{\varphi, \theta} \sim 10^5$-$10^6$~km at PSP, and L$_{\varphi, \theta} \sim 10^6$-$10^7$~km at SolO. This implies a strong evolution of the structure's aspect ratio during the propagation, due to the plasma's nearly spherical expansion. The structure's shape is therefore inferred to evolve from elongated in the radial direction at $\sim$2-3 solar radii (high corona), to sizes of nearly the same order in all directions at PSP, and then becoming elongated in the directions transverse to the radial at SolO. Measurements are not concordant with local reconnection of open solar wind field lines, so we propose that the structure has been generated through interchange reconnection near the tip of a coronal streamer.

The detection of water molecules within the atmosphere of Jupiter, first by the Galileo Atmospheric Probe, and later by the Juno spacecraft, has given rise to the question of whether those molecules are sourced endogenously or exogenously. One hypothesis is that the ablation of meteoroids deposited the necessary oxygen into the atmosphere, which was subsequently used in chemical processes to form water. This paper aims to evaluate this hypothesis by simulating the ablation of carbonaceous objects entering the planet's atmosphere to determine the possible rates of oxygen delivery and the most likely altitude for such delivery within the Jovian atmosphere. We estimate that carbonaceous meteoroids have the potential to deliver $\sim 1.4 \times 10^7 \, \text{kg/m}^2$ of oxygen over a billion years. We further estimate that most of the ablation is expected to occur in the stratosphere, or 450-400 km above the region of 1 bar of atmospheric pressure. In comparison, Interplanetary Dust Particles (IDPs) are estimated to deliver roughly $\sim 10^2 \, \text{kg/m}^2$ of oxygen over the same period.

As there is a long-standing controversy over the time delay between the two images of the gravitationally lensed quasar FBQ 0951+2635, we combined early and new optical light curves to robustly measure a delay of 13.5 +/- 1.6 d (1sigma interval). The new optical records covering the last 17 yr were also used to trace the long-timescale evolution of the microlensing variability. Additionally, the new time delay interval and a relatively rich set of further observational constraints allowed us to discuss the mass structure of the main lensing galaxy at redshift 0.26. This lens system is of particular interest because the external shear from secondary gravitational deflectors is relatively low, but the external convergence is one of the highest known. When modelling the galaxy as a singular power-law ellipsoid without hypotheses/priors on the power-law index, ellipticity and position angle, we demonstrated that its mass profile is close to isothermal, and there is good alignment between mass and near-IR light. We also recovered the true mass scale of the galaxy. Finally, it is worth mentioning that a constant mass-to-light ratio model also worked acceptably well.

Models of active galactic nuclei often invoke a close physical association between the broad-line region and the accretion disk. We evaluate this theoretical expectation by investigating the relationship between the inclination angle of the BLR ($\theta_\mathrm{BLR}$) and the inclination angle of the inner accretion disk ($\theta_\mathrm{disk}$). For a sample of eight active galactic nuclei that have published values of $\theta_\mathrm{BLR}$ estimated from dynamical modeling of the BLR based on velocity-resolved reverberation mapping experiments, we analyze high-quality, joint XMM-Newton and NuSTAR X-ray observations to derive new, robust measurements of $\theta_\mathrm{disk}$ through broadband (0.3--78\,keV) reflection spectroscopy. We find a strong, positive correlation between $\theta_\mathrm{BLR}$ and $\theta_\mathrm{disk}$ (Pearson correlation coefficient 0.856, $p$-value 0.007), although Monte Carlo simulations indicate that the level of significance is only marginal ($<3\,\sigma$). Nevertheless, the nearly linear relation between $\theta_\mathrm{BLR}$ and $\theta_\mathrm{disk}$ suggests of a possible physical alignment between the accretion disk and the BLR. Future studies with a larger and more homogeneous sample are needed to confirm the correlation and refine our understanding of the structure and dynamics of the central regions of active galaxies.

We revisit the launch of the galactic outflow in M82 through high-resolution hydrodynamic simulations. Employing a sink-particle module, we self-consistently resolve the star formation and feedback processes, avoiding the reliance on various assumed models as in previous works. We probe the effects of different stellar feedback mechanisms, the gas return from star-forming clouds and initial gas disc mass on the starburst and launch of outflow. Our simulations can generate a starburst that lasts 20-30 Myr, peaking at 20-50 $\rm{M_{\odot} yr^{-1}}$. However, the total stellar mass formed in the starburst in our simulations often exceeds M82's estimated value. The outflow's launch occurs in two stages. Initially, continuous SNe explosions form numerous small bubbles, merging into a super bubble foam composed of low-density warm/hot gas and high-density cool filaments. After approximately 10 Myr of SN energy injection, the super bubble breakout the disc, marking the second stage, which takes 10-15 Myr to develop a multiphase, kpc-scale outflow. Our simulations reveal that cool filaments within the turbulent ISM can survive from the feedback associated to the starburst, then were entrained into the outflow and stretched to hundreds pc in length due to interaction with the hot wind. While the mass loading factor of the well-developed outflow is comparable to M82, the cool gas mass outflow rate is often lower, and its velocity is slower than the estimated value in M82 by $50\%-60\%$. Warm and hot gas are $20\%-30\%$ slower. SN feedback acts as the primary driver of the outflow, while gas return significantly influences the starburst and outflow properties. The initial mass of gas disc has a moderate effect, while stellar wind and radiation feedback have minor effect. To address the shortcomings in our results, enhanced SN feedback effect, due to clustered SNe, is likely necessary.

Massive stars are key contributors to the chemodynamical evolution of galaxies and the Universe. Despite their significance, discrepancies between observational data and theoretical models of massive stars challenge our understanding of these objects. A major uncertainty is the overdensity of B-type supergiants (BSGs) in the Hertzsprung-Russell diagram, where models predict the end of the main sequence phase (or TAMS). Is uncertain whether the TAMS needs to be redefined or if the overdensity results from overlapping populations following different evolutionary paths. Conceived as direct descendants of O-type stars, BSGs may include stars not only evolving in the main sequence but also returning from a post-red supergiant phase. A representative fraction of massive stars are predicted to be products of binary interaction, creating additional evolutionary channels. In addition, some fundamental properties of BSGs such as the spin- and mass-loss rates are not as well constrained as in O-type stars, having a significant impact on massive star evolution. To overcome this situation, statistically significant spectroscopic samples offer a unique opportunity to study the physical and chemical properties of BSGs. Moreover, the advent of space astrometry and photometry missions such as Gaia and TESS has brought a new era for studying additional properties in detail. This thesis comprises the study of 1000 Galactic blue supergiants (O- and B-type) combining multi-epoch high-resolution spectroscopic data from the IACOB project and the ESO archive with Gaia distances and TESS photometry, becoming the largest holistic empirical study of the physical, chemical, and pulsational properties of these objects performed to date. All these properties gathered into a unique volume-limited sample allowed to provide an empirical reassessment of the main properties of BSGs and investigate their intricate nature.

We search for the stochastic gravitational-wave background (SGWB) predicted by pre-big-bang (PBB) cosmology using data from the first three observing runs of Advanced LIGO and Advanced Virgo. PBB cosmology proposes an alternative to cosmic inflation where the Universe evolves from a weak-coupling, low-curvature state to the hot Big Bang through a high-curvature bounce phase, predicting a distinctive SGWB spectrum. We perform a Bayesian analysis of the cross-correlation data to constrain the model parameters characterizing the PBB spectrum. We find no evidence for a PBB-induced SGWB, with a Bayes factor of $0.03$ between the PBB and noise-only model, strongly favoring the noise-only hypothesis. Our analysis establishes a lower bound $\beta \gtrsim -0.19$ at $95\%$ confidence level, which is compatible with the theoretical requirement $\beta \geq 0$ for a smooth bounce transition. While we do not detect a signal, our constraints remain consistent with the basic theoretical framework of PBB cosmology, demonstrating the potential of gravitational-wave observations to test early Universe theories.

SIRI-2 is a collection of Strontium Iodide gamma-ray detectors sensitive at approximately 400 keV to 10 MeV, launched on the Department of Defense's STPSat-6 to geosynchronous orbit. SIRI-2 detected the gamma-ray burst (GRB) 221009A and, unlike most GRB detectors, was not saturated and did not require any pulse pile-up corrections. The energetics of this burst as measured by SIRI-2 are consistent with those found by other instruments, and the Band function fits to the spectra are consistent with that from the unsaturated Insight and GECAM instruments, and similar to corrected spectra from the Fermi Gamma-ray Burst Monitor, but softer than those found by Konus-Wind when that instrument was saturated. The total fluence measured with SIRI-2 was measured to be 0.140 +/- 0.002 erg cm-2, lower than other instruments, likely due to the increasing background of SIRI-2 forcing the calculation to use a smaller time interval. An extrapolation of the distributions of fluences from GRBs to the fluence of 221009A measured with SIRI-2 indicates bursts brighter than this one should occur about once every 4,000 years.

A measurement of the redshift drift constitutes a model-independent probe of fundamental cosmology. Several approaches are being considered to make the necessary observations, using (i) the Extremely Large Telescope (ELT), (ii) the Cosmic Accelerometer, and (iii) the differential redshift drift methodology. Our focus in this {\it Letter} is to assess how these upcoming measurements may be used to compare the predictions of $\Lambda$CDM with those of the alternative Friedmann-Lemaître-Robertson-Walker cosmology known as the $R_{\rm h}=ct$ universe, and several other models, including modified gravity scenarios. The ELT should be able to distinguish between $R_{\rm h}=ct$ and the other models at better than $3\sigma$ for $z\gtrsim 3.6$ after 20 years of monitoring, while the Cosmic Accelerometer may be able to achieve the same result with sources at $z\gtrsim 2.6$ after only 10 years.

Most of the visible matter in the Universe is in a gaseous state, subject to hydrodynamic forces and galaxy formation processes that are much more complex to model than gravity. These baryonic effects can potentially bias the analyses of several cosmological probes, such as weak gravitational lensing. In this work, we study the gas density and velocity fields of the FLAMINGO simulations and compare them with their gravity-only predictions. We find that, while the gas velocities do not differ from those of dark matter on large scales, the gas mass power spectrum is suppressed by up to $\approx 8\%$ relative to matter, even on gigaparsec scales. This is a consequence of star formation depleting gas in the densest and most clustered regions of the universe. On smaller scales, $k>0.1 \, h / \rm Mpc$, the power suppression for both gas densities and velocities is more significant and correlates with the strength of the active galactic nucleus (AGN) feedback. The impact of feedback can be understood in terms of outflows, identified as gas bubbles with positive radial velocities ejected from the central galaxy. With increasing feedback strength, the outflowing gas has higher velocities, and it reaches scales as large as $10$ times the virial radius of the halo, redistributing the gas and slowing its average infall velocity. Interestingly, different implementations of AGN feedback leave distinct features in these outflows in terms of their radial and angular profiles and their dependence on halo mass. In the future, such differences could be measured in observations using, for example, the kinetic Sunyaev-Zeldovich effect.

The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is an upcoming radio interferometric telescope designed to constrain dark energy through the 21cm intensity mapping of Baryon Acoustic Oscillations (BAO). Instrumental systematics must be controlled and carefully characterized to measure the 21cm power spectrum with fidelity and achieve high-precision constraints on the cosmological parameters. The chromaticity of the primary beam is one such complicated systematic, which can leak the power of spectrally smooth foregrounds beyond the ideal horizon limits due to the complex spatial and spectral structures of the sidelobes and the mainlobe. This paper studies the chromaticity of the HIRAX Stokes I primary beam and its effects on accurate measurements of the 21cm power spectrum. To investigate the effect of chromaticity in the 21cm power spectrum, we present a physically motivated beam modeling technique, which uses a flexible basis derived from traditional optics that can account for higher-order radial and azimuthal structures in the primary beam. We investigate the impact of imperfect knowledge of the mainlobe and sidelobes chromaticity in the power spectrum space by subtracting a simple foreground model in simulated snapshot visibilities to recover the H$\textsc{i}$ power spectrum. Additionally, we find that modeling up to the octupolar azimuthal order feature (fourth-order angular variation) in the primary beam is sufficient to reduce the leakage outside the wedge with minimal bias.

Quadrature Hybrid Couplers (QHDC) are critical components in RF, mm-wave, and sub-mm wave astronomical instrumentation, where wideband performance with minimal passband ripple is essential. Traditional designs have been limited to 5-sections at most due to computational limitations. In this work, we introduce a new analytical technique to design couplers with larger sections and improved performance. We do this by employing a Markov Chain Monte Carlo (MCMC) based solver. By defining a likelihood function based on S-parameter equations and incorporating physical priors, we derive optimized impedance values that enhance bandwidth beyond what is reported in the literature. Our flexible pipeline allows efficient tuning of the coupler design. The results demonstrate fractional bandwidths that reach 1.0 for a 9-section coupler, substantially outperforming previous designs. Statistical analysis and convergence tests confirm the robustness of our approach.

The study of large-scale structure can benefit from accurate and robust identification of the cosmic web. Having such classification can facilitate a more complete extraction of cosmological information encoded therein. Classification methods like T-web and V-web, based on the Hessian matrix, are widely used to signal-out voids, sheets, filaments, and knots. However, these techniques depend on a threshold parameter which value is chosen without physical justification, usually relying on a user visual impression, thus limiting the universality of results. In this paper we focus on the V-web method. Our aim is to find a physical motivation for deriving an universal threshold that can be applied across different cosmic scales and epochs. V-web classify the large-scale structure using the eigenvalues of the velocity shear tensor. Using a set of gravity-only simulations we introduce a normalization that incorporates the standard deviation of the velocity divergence field, isolating the beyond Gaussian evolution of cosmic web elements. In the Zeldovich's approximation, the probability presence of each cosmic web element remains constant at a threshold equal to 0. For the first time, we reveal that this behavior also holds in the non-linear regime for a normalized positive 'constant volume threshold' that depends on both the redshift and the applied smoothing scale. The conservation of volume fractions is valid for the studied redshifts between 0 and 2, regardless of cosmic variance, and is most precise for intermediate smoothing scales around 3 Mpc/h. The properties of the cosmic web derived using this approach in the V-web align with expectations from other methods, including visual impressions. We provide a general fit formula to compute the constant volume threshold for any standard cosmological simulation, regardless of its specific properties.

Astrophysical relativistic outflows are launched as Poynting-flux-dominated, yet the mechanism governing efficient magnetic dissipation, which powers the observed emission, is still poorly understood. We study magnetic energy dissipation in relativistic "striped" jets, which host current sheets separating magnetically dominated regions with opposite field polarity. The effective gravity force $g$ in the rest frame of accelerating jets drives the Kruskal-Schwarzschild instability (KSI), a magnetic analogue of the Rayleigh-Taylor instability. By means of 2D and 3D particle-in-cell simulations, we study the linear and non-linear evolution of the KSI. The linear stage is well described by linear stability analysis. The non-linear stages of the KSI generate thin (skin-depth-thick) current layers, with length comparable to the dominant KSI wavelength. There, the relativistic drift-kink mode and the tearing mode drive efficient magnetic dissipation. The dissipation rate can be cast as an increase in the effective width $\Delta_{\rm eff}$ of the dissipative region, which follows $d\Delta_{\rm eff}/dt\simeq 0.05 \sqrt{\Delta_{\rm eff}\,g}$. Our results have important implications for the location of the dissipation region in gamma-ray burst and AGN jets.

Magnetic flux tubes in the solar corona support a rich variety of transverse oscillations, which are theoretically interpreted as magnetohydrodynamic (MHD) modes with a fast and/or Alfvénic character. In the standard flux tube model made of a straight cylindrical tube, these modes can be classified according to their azimuthal wavenumber, $m$. Sausage $m=0$ modes produce periodic expansion and contraction of the tube cross section and are observed during solar flares. Kink $m=1$ modes laterally displace the tube axis and are related to, for example, post-flare global transverse oscillations of coronal loops. Fluting $m \geq 2$ modes produce disturbances that are mainly confined to the tube boundary, but their observation remains elusive to date. We use 3D ideal MHD numerical simulations to investigate the nonlinear evolution of fluting modes in coronal flux tubes with transversely nonuniform boundaries. The simulations show that fluting modes are short-lived as coherent, collective motions of the flux tube. Owing to the process of resonant absorption, fluting oscillations become overdamped modes in tubes with wide enough nonuniform boundaries. During the nonlinear evolution, shear flows drive the Kelvin-Helmholtz instability at the tube boundary, which further disrupts the coherent fluting oscillation. For large-enough oscillation amplitudes, baroclinic instabilities of Rayleigh-Taylor type are also present at locations in the boundary where the plasma acceleration is normal to the boundary. The evolution of the instabilities drives turbulence in the flux tube, which may inhibit the resonant damping. However, the oscillations remain strongly damped even in this case. As a result of the combination of the strong damping and the induced instabilities, it is unlikely that coronal flux tubes can support fluting modes as sufficiently enduring coherent oscillations.

One regime where we might see departures from general relativity is at the largest accessible scales, with a natural choice in cosmology being the cosmological horizon (or Hubble) scale. We investigate a single-parameter extension to the standard cosmological model with a different strength of gravity above and below this scale -- a "cosmic glitch" in gravity. Cosmic microwave background observations, and Baryonic Acoustic Oscillations (including the recent DESI Y1) favour weaker superhorizon gravity, at nearly a percent (or 2$\sigma$ level), easing both the Hubble and clustering tensions with other cosmological data. This compounds evidence for an even stronger glitch during Big Bang nucleosynthesis (from helium abundance observations), suggesting that symmetries of general relativity are maximally violated at the Big Bang, but gradually recovered as we approach the present-day cosmological de Sitter scale, associated with the observed dark energy.

Protoplanetary disks can exhibit asymmetric temperature variations due to phenomena such as shadows cast by the inner disk or localized heating by young planets. We have performed both linear analyses and hydrodynamical simulations to investigate the disk perturbations induced by these asymmetric temperature variations. Our findings demonstrate that the effects of temperature variations share similarities with those caused by external potentials. Specifically, rotating temperature variations launch steady spiral structures at Lindblad resonances, which corotate with the temperature patterns. When the cooling time exceeds the orbital period, these spiral structures are significantly weakened. Then, depending on the boundary condition, a checkerboard pattern can appear. We provide expressions for the amplitudes of the resulting density and velocity perturbations, primarily determined by the magnitude of the temperature variations. Notably, a temperature variation of about 10\% can induce spirals with density perturbation amplitudes of order unity, comparable to those generated by a thermal mass planet. The coupling between temperature variations and spirals outside the resonances leads to a radially varying angular momentum flux, which could result in efficient ring formation within the disk. We speculate that spirals induced by temperature variations may contribute to disk accretion. Overall, considering that irradiation determines the temperature structure of protoplanetary disks, the change of irradiation both spatially or/and temporarily may produce observable effects in protoplanetary disks, especially spirals in outer disks beyond tens of AU.

We present the results of a study investigating the galaxy stellar-mass function (GSMF), size-mass relations and morphological properties of star-forming and quiescent galaxies over the redshift range $0.25<z<2.25$, using the JWST PRIMER survey. The depth of the PRIMER near-IR imaging allows us to confirm the double Schechter function shape of the quiescent GSMF out to $z\simeq2.0$, via a clear detection of the upturn at $\mathrm{log}_{10}(M_{\star}/ M_{\odot}) \leq 10$ thought to be induced by environmental quenching. In addition to the GSMF, we confirm that quiescent galaxies can be split into separate populations at $\mathrm{log}_{10}(M_{\star}/M_{\odot}) \simeq 10$, based on their size-mass relations and morphologies. We find that low-mass quiescent galaxies have more disk-like morphologies (based on Sérsic index, Gini coefficient and $M_{20}$ metrics) and follow a shallower size-mass relation than their high-mass counterparts. Indeed, the slope of the size-mass relation followed by low-mass quiescent galaxies is indistinguishable from that followed by star-forming galaxies, albeit with a lower normalization. Moreover, within the errors, the evolution in the median size of low-mass quiescent galaxies is indistinguishable from that followed by star-forming galaxies ($R_{e}\propto(1+z)^{-0.25\pm0.03})$, and significantly less rapid than that displayed by high-mass quiescent galaxies ($R_{e}\propto (1+z)^{-1.14\pm 0.03})$. Overall, our results are consistent with low and high-mass quiescent galaxies following different quenching pathways. The evolution of low-mass quiescent galaxies is qualitatively consistent with the expectations of external/environmental quenching (e.g. ram-pressure stripping). In contrast, the evolution of high-mass quiescent galaxies is consistent with internal/mass quenching (e.g. AGN feedback) followed by size growth driven by minor mergers.

The quantum speed limits (QSLs) determine the minimal amount of time required for a quantum system to evolve from an initial to a final state. We investigate QSLs for the unitary evolution of the neutrino-antineutrino system in the presence of a gravitational field. It is known that the transition probabilities between neutrino and antineutrino in the framework of one and two flavors depend on the strength of the gravitational field. The behavior of the QSL time in the two-flavor system indicates fast flavor transitions as the gravitational field strength increases. Subsequently, we observe quick suppression of entanglement by exploring the speed limit for entanglement entropy of two-flavor oscillations in the neutrino-antineutrino system in the proximity of a spinning primordial black hole.

We investigate the quantum speed limit (QSL) during the time evolution of neutrino-antineutrino system under the influence of the gravitational field of a spinning primordial black hole (PBH). We derive an analytical expression for the four-vector gravitational potential in the underlying Hermitian Dirac Hamiltonian using the Boyer-Lindquist (BL) coordinates. This gravitational potential leads to an axial vector term in the Dirac equation in curved spacetime, contributing to the effective mass matrix of the neutrino-antineutrino systems. Our findings indicate that the gravitational field, expressed in BL coordinates, significantly influences the transition probabilities in two-flavor oscillations of the neutrino-antineutrino system. We then apply the expression for transition probabilities between states to analyze the Bures angle, which quantifies the closeness between the initial and final states of the time-evolved flavor state. We use this concept to probe the QSL for the time evolution of the initial flavor neutrino state.

With the rapid development of gravitational wave astronomy, the increasing number of detected events necessitates efficient methods for parameter estimation and model updates. This study presents a novel approach using knowledge distillation techniques to enhance computational efficiency in gravitational wave analysis. We develop a framework combining ResNet1D and Inverse Autoregressive Flow (IAF) architectures, where knowledge from a complex teacher model is transferred to a lighter student model. Our experimental results show that the student model achieves a validation loss of 3.70 with optimal configuration (40,100,0.75), compared to the teacher model's 4.09, while reducing the number of parameters by 43\%. The Jensen-Shannon divergence between teacher and student models remains below 0.0001 across network layers, indicating successful knowledge transfer. By optimizing ResNet layers (7-16) and hidden features (70-120), we achieve a 35\% reduction in inference time while maintaining parameter estimation accuracy. This work demonstrates significant improvements in computational efficiency for gravitational wave data analysis, providing valuable insights for real-time event processing.

Formulating a quantum theory of gravity lies at the heart of fundamental theoretical physics. This collection of lecture notes encompasses a selection of topics that were covered in six mini-courses at the Nordita PhD school "Towards Quantum Gravity". The scope was to provide a coherent picture, from its foundation to forefront research, emphasizing connections between different areas. The lectures begin with perturbative quantum gravity and effective field theory. Subsequently, two ultraviolet-complete approaches are presented: asymptotically safe gravity and string theory. Finally, elements of quantum effects in black hole spacetimes are discussed.

To deepen our understanding of Quantum Gravity and its connections with black holes and cosmology, building a common language and exchanging ideas across different approaches is crucial. The Nordita Program "Quantum Gravity: from gravitational effective field theories to ultraviolet complete approaches" created a platform for extensive discussions, aimed at pinpointing both common grounds and sources of disagreements, with the hope of generating ideas and driving progress in the field. This contribution summarizes the twelve topical discussions held during the program and collects individual thoughts of speakers and panelists on the future of the field in light of these discussions.

The quantum chromodynamics (QCD) axion arises as the pseudo-Goldstone mode of a spontaneously broken abelian Peccei-Quinn (PQ) symmetry. If the scale of PQ symmetry breaking occurs below the inflationary reheat temperature and the domain wall number is unity, then there is a unique axion mass that gives the observed dark matter (DM) abundance. Computing this mass has been the subject of intensive numerical simulations for decades since the mass prediction informs laboratory experiments. Axion strings develop below the PQ symmetry-breaking temperature, and as the string network evolves it emits axions that go on to become the DM. A key ingredient in the axion mass prediction is the spectral index of axion radiation emitted by the axion strings. We compute this index in this work using the most precise and accurate large-scale simulations to date of the axion-string network leveraging adaptive mesh refinement to achieve the precision that would otherwise require a static lattice with 262,144$^3$ lattice sites. We find a scale-invariant axion radiation spectrum to within 1% precision. Accounting for axion production from strings prior to the QCD phase transition leads us to predict that the axion mass should be approximately $m_a\in(45,65)$ $\mu \mathrm{eV}$. However, we provide preliminary evidence that axions are produced in greater quantities from the string-domain-wall network collapse during the QCD phase transition, potentially increasing the mass prediction to as much as 300 $\mu$eV.

We carefully analyse the challenges posed by the construction of type IIB chiral global embeddings of Fibre Inflation with $\overline{ \rm D3}$ uplift to a de Sitter vacuum. We present an explicit example involving an $h^{1,1}=4$ Calabi-Yau manifold with a K3 fibration and a del Pezzo divisor supporting non-perturbative effects. The chosen orientifold involution induces O3-planes that can be placed on top of each other at the tip of the throat of a deformed conifold singularity. The D7-brane sector contains standard magnetised branes and a Whitney brane. The former induce chiral matter and generate quantum effects that stabilise the Kähler moduli, while the latter helps increasing the total D3-charge. We study in detail the constraints on the parameter space leading to an observationally viable inflationary dynamics, finding several regions where the effective field theory is under control.

The search for axions and axion-like particles (ALPs) remains a major endeavor in modern physics investigation. Axions play essential roles in the quest to understand dark matter, the strong CP problem, and various astrophysical phenomena. This paper provides a very brief overview of the current status of experimental efforts, highlighting significant advancements, ongoing projects, and future opportunities. Particular attention is given to cavity haloscopes, helioscopes, and laboratory-based light-shining-through-wall experiments, as well as astrophysical probes. Some future perspectives are also discussed.

I show that in addition to the well-known peak inside massive neutron stars, the sound speed in cold dense QCD matter likely exhibits another peak above neutron star densities before it asymptotes to $c_s=\sqrt{C_s}=\sqrt{1/3}$. Based on the framework reported in arXiv:2408.16738, this approach does not rely on any assumption about the ultra-dense matter not realized in nature. Current multimessenger observation of neutron stars favors the two-peak scenario with a Bayes factor $5.1_{-0.7}^{+0.9}$, where the uncertainties are systematics due to models of neutron star inner cores. This evidence grows to $27_{-8}^{+11}$ if the $2.6M_\odot$ component of GW190814 is a neutron star. The trough in $C_s$ separating the two peaks is inferred to be below $0.05^{+0.04}_{-0.02}$ (at the $50\%$ level) if $2.6M_\odot$ neutron stars exist. The second peak above $1/3$ beyond baryon chemical potential $\mu_B=1.6-1.9$ GeV most likely signals non-perturbative effects in cold quark matter, for instance color superconductivity.

As superconducting kinetic inductance detectors (KIDs) continue to grow in popularity for sensitive sub-mm detection and other applications, there is a drive to advance toward lower loss devices. We present measurements of diagnostic thin film aluminum coplanar waveguide (CPW) resonators designed to inform ongoing KID development at NASA Goddard Space Flight Center. The resonators span $\rm f_0 = 3.5 - 4$\,GHz and include both quarter-wave and half-wave resonators with varying coupling capacitor designs. We present measurements of the device film properties and an analysis of the dominant mechanisms of loss in the resonators measured in a dark environment. We demonstrate quality factors of $\rm Q_i^{-1} \approx 3.64 - 8.57 \times10^{-8}$, and observe enhanced suppression of two-level system (TLS) loss in our devices at high internal microwave power levels before the onset of quasiparticle dissipation from microwave heating. We observe deviations from the standard TLS loss model at low powers and temperatures below 60 mK, and use a modified model to describe this behavior.

We present an investigation into the effects of high-energy proton damage on charge trapping in germanium cross-strip detectors, with the goal of accomplishing three important measurements. First, we calibrated and characterized the spectral resolution of a spare COSI-balloon detector in order to determine the effects of intrinsic trapping, finding that electron trapping due to impurities dominates over hole trapping in the undamaged detector. Second, we performed two rounds of proton irradiation of the detector in order to quantify, for the first time, the rate at which charge traps are produced by proton irradiation. We find that the product of the hole trap density and cross-sectional area, $[n\sigma]_\mathrm{h}$ follows a linear relationship with the proton fluence, $F_\mathrm{p}$, with a slope of $(5.4\pm0.4)\times10^{-11}\,\mathrm{cm/p^{+}}$. Third, by utilizing our measurements of physical trapping parameters, we performed calibrations which corrected for the effects of trapping and mitigated degradation to the spectral resolution of the detector.

In this work we constrain the value of $\sigma_8$ for the normal and self-accelerating branch of a DGP brane embedded in a five-dimensional Minkowski space-time. For that purpose we first constrain the model parameters $H_0$, $\Omega_{m0}$, $\Omega_{r0}$ and $M$ by means of the Pantheon+ catalog and a mock catalog of gravitational waves. Then, we solve numerically the equation for dark matter scalar perturbations using the dynamical scaling solution for the master equation and assuming that $p=4$ for the matter dominated era. Finally, we found that the evolution of matter density perturbations in both branches is different from the $\Lambda$CDM model and that the value of $\sigma_8=0.774\pm0.027$ for the normal branch and $\sigma_8=0.913\pm0.032$ for the self-accelerating branch.

Hamiltonian and Langevin Monte Carlo (HMC and LMC) and their Microcanonical counterparts (MCHMC and MCLMC) are current state of the art algorithms for sampling in high dimensions. Their numerical discretization errors are typically corrected by the Metropolis-Hastings (MH) accept/reject step. However, as the dimensionality of the problem increases, the stepsize (and therefore efficiency) needs to decrease as $d^{-1/4}$ for second order integrators in order to maintain reasonable acceptance rate. The MH unadjusted methods, on the other hand, do not suffer from this scaling, but the difficulty of controlling the asymptotic bias has hindered the widespread adoption of these algorithms. For Gaussian targets, we show that the asymptotic bias is upper bounded by the energy error variance per dimension (EEVPD), independently of the dimensionality and of the parameters of the Gaussian. We numerically extend the analysis to the non-Gaussian benchmark problems and demonstrate that most of these problems abide by the same bias bound as the Gaussian targets. Controlling EEVPD, which is easy to do, ensures control over the asymptotic bias. We propose an efficient algorithm for tuning the stepsize, given the desired asymptotic bias, which enables usage of unadjusted methods in a tuning-free way.

We propose a novel paradigm for the QCD axion with high-quality Peccei-Quinn (PQ) symmetry on the basis of electric-magnetic duality in the conformal window of a supersymmetric gauge theory. PQ breaking fields, that contain the QCD axion, emerge in the magnetic theory and possess a large anomalous dimension, which leads to not only generation of an intermediate scale of spontaneous PQ breaking but also significant suppression of explicit PQ symmetry breaking operators. The high PQ quality and the absence of a Landau pole in the color gauge coupling are achieved. The parameter space to realize the correct abundance of the axion dark matter (DM) predicts explicit PQ violation which may be probed by future measurements of the neutron electric dipole moment. In the other viable parameter space, the lightest supersymmetric particle can become a DM candidate. Since the model naturally accommodates a mechanism to suppress the axion isocurvature fluctuation, it provides a complete solution to the strong CP problem as well as the identity of DM.

We study the intrinsic and extrinsic torsions (defined by analogy with the intrinsic and extrinsic curvatures) of the spatial sections of torsional spacetimes. We consider two possibilities. First, that the intrinsic torsion might prove to be directly observable. Second, that it is not observable, having been ``inflated away'' in the early Universe. We argue that, even in this second case, the extrinsic torsion may grow during the inflationary era and be non-negligible at reheating and thereafter. Even if the spatial intrinsic curvature and torsion are too small to be detected directly, then, the extrinsic torsion might not be. We point out that, if its presence is not recognised, the extrinsic torsion could lead to anomalies in the theoretical estimate of the Hubble parameter, a result with obvious potential applications. We stress that extrinsic torsion is by far the most natural way to produce such anomalies, simply because it mixes naturally with the Hubble parameter.

Even in the absence of neutrino masses, a neutrino gas can exhibit a homogeneous flavor instability that leads to a periodic motion known as the fast flavor pendulum. A well-known necessary condition is a crossing of the angular flavor lepton distribution. However, in contrast to an earlier finding by two of us, the Nyquist criterion inspired by plasma physics, while being a more restrictive necessary condition, is not always sufficient. The question depends on the unstable branch of the dispersion relation being bounded by critical points that both lie under the light cone (points with subluminal phase velocity), in which case the Nyquist criterion is sufficient. While the lepton-number angle distribution, assumed to be axially symmetric, easily allows one to determine the real branch of the dispersion relation and to recognize if instead superluminal critical points exist, this graphical method does not translate into a simple instability condition. We discuss the dispersion relation for the homogeneous mode in the more general context of modes with arbitrary wave number and stress that it plays no special role on this continuum, except for its regular but fragile long-term behavior owed to its many symmetries.

We connect nuclear forces to one of the most notable irregular behaviors observed in pulsars, already detected in approximately 6\% known pulsars, with increasingly accurate data expected from upcoming high-precision timing instruments on both ground and space. Built on \cite{Shang2021_ApJ923-108}, we conduct a case study on the 2001 glitch of the Vela pulsar. For our purpose, we adopt the Relativistic Mean Field (RMF) model as the theoretical many-body framework to describe nuclear systems. We refit three representative RMF parameter sets (DD-ME2, PKDD, NL3), considering the uncertainties in nuclear matter saturation properties. Utilizing the resulting star structure, composition and nucleon properties in the medium obtained in a consistent manner, we calculate the pinning energy of superfluid vortex in the nuclear lattice in the inner crust. This leads to the evolution of associated pinning force that acts on the vortex, which can be confronted with observed glitch amplitude and short-time relaxation in the 2000 Vela glitch event, following the superfluidity model of pulsar glitch. We discuss how the vortex configuration and pinning properties depend on the nuclear parameters, and find an interesting and dominant role of the nuclear symmetry energy slope on pinning strength.

Electromagnetic radiation of a relativistic gas or plasma jet in the field of a plane gravitational wave is investigated. The gravitational wave is considered as a weak (linearized) field on flat Minkowski spacetime. It is assumed that the relativistic jet has large regions with uncompensated electric charge. The deformation of these areas under the action of a gravitational wave leads to the appearance of electric currents that generate electromagnetic radiation. The angular distribution of the intensity of this radiation is found. Cases are considered when the jet and the gravitational wave move in the same direction or towards each other.

The recently developed extended Skyrme effective interaction based on the so-called N3LO Skyrme pseudopotential is generalized to the general N$n$LO case by incorporating the derivative terms up to 2$n$th-order into the central term of the pseudopotential. The corresponding expressions of Hamiltonian density and single-nucleon potential are derived within the Hartree-Fock approximation under general nonequilibrium conditions. The inclusion of the higher-order derivative terms provides additional higher-order momentum dependence for the single-nucleon potential, and in particular, we find that the N5LO single-nucleon potential with momentum dependent terms up to $p^{10}$ can give a nice description for the empirical nucleon optical potential up to energy of $2$ GeV. At the same time, the density-dependent terms in the extended Skyrme effective interaction are extended correspondingly in the spirit of the Fermi momentum expansion, which allows highly flexible variation of density behavior for both the symmetric nuclear matter equation of state and the symmetry energy. Based on the Skyrme pseudopotential up to N3LO, N4LO and N5LO, we construct a series of interactions with the nucleon optical potential having different high-momentum behaviors and the symmetry potentials featuring different linear isospin-splitting coefficients for nucleon effective mass, by which we study the properties of nuclear matter and neutron stars. Furthermore, within the lattice BUU transport model, some benchmark simulations with selected interactions are performed for the Au+Au collisions at a beam energy of $1.23$ GeV/nucleon, and the predicted collective flows for protons are found to nicely agree with the data measured by HADES collaboration.

Dark matter (DM) within the solar system induces deviations in the geodetic drift of gyroscope spin due to its gravitational interaction. Assuming a constant DM density as a minimal scenario, we constrain DM overdensity within the Gravity Probe B (GP-B) orbit and project limits for Earth's and Neptune's orbits around the Sun. The presence of electrons in gravitating sources and test objects introduces a scalar-mediated Yukawa potential, which can be probed using terrestrial and space--based precision clocks. We derive projected DM overdensity $(\eta)$ limits from Sagnac time measurements using onboard satellite clocks, highlighting their dependence on the source mass and orbital radius. The strongest limit, $\eta\lesssim 4.45\times 10^3$, is achieved at Neptune's orbit ($\sim 30~\mathrm{AU}$), exceeding existing constraints. Correspondingly, the cosmic neutrino overdensity is bounded as $\xi\lesssim 5.34\times 10^{10}$, surpassing results from KATRIN and cosmic ray studies. The best limit on electrophilic scalar coupling is $g\lesssim 7.09\times 10^{-24}$ for scalar mass $m_\varphi\lesssim 1.32\times 10^{-18}~\mathrm{eV}$ competitive with existing fifth-force bounds. These precision measurements offer a robust framework for testing gravity at solar system scales and probing DM in scenarios inaccessible to direct detection experiments.

In this article, we claim that axion-like particles (ALPs) with MeV masses can be produced with semi-relativistic velocities in core-collapse supernovae (SNe), generating a diffuse galactic flux. We show that these ALPs can be detected in neutrino water Cherenkov detectors via $a \, p \rightarrow p \, \gamma$ interactions. Using Super-Kamiokande data, we derive new constraints on the ALP parameter space, excluding a region spanning more than one order of magnitude in the ALP-proton coupling above cooling bounds for ALP masses in the range of $1-80$ MeV and ALP-proton couplings between $6\times10^{-6}-2\times10^{-4}$. We show that the future Hyper-Kamiokande will be able to probe couplings as small as $2\times10^{-6}$, fully closing the allowed region above SN 1987A cooling bounds.