Papers for Wednesday, Aug 21 2024

We study observational signatures of the hadron-quark crossover in binary-neutron-star mergers by systematic numerical-relativity simulations. We employ two equations of state (EoSs) for matter consistent with inference from the observational data. In the crossover scenario the EoS is softened in a density realized in binary-neutron-star mergers and is smoothly continued to quark matter. In the phase transition scenario without crossover, the EoS remains stiff and a first-order phase transition takes place in a density out of reach of mergers. A GW170817-like system forms a remnant massive neutron star in both scenarios, and only the crossover scenario makes it collapse into a black hole due to the softening while gravitational-wave emission is strong. This difference is clearly reflected in the sudden shutdown of gravitational waves. For a given EoS, the lifetime of the merger remnant is determined primarily by the total mass of the system. These features pave the way for clarifying details of hadron-quark transition by compiling a wide variety of events observed with future gravitational-wave detectors. The mass of the accretion disk surrounding the remnant black hole is affected not only by the lifetime of the remnant but also by the mass ratio of the system. Electromagnetic emission associated with the disk outflow will also be useful for detailed investigation of the hadron-quark transition.

GQ Lup B is one of the few substellar companions with a detected cicumplanetary disk, or CPD. Observations of the CPD suggest the presence of a cavity, possibly formed by an exo-satellite. Using the Keck Planet Imager and Characterizer (KPIC), a high contrast imaging suite that feeds a high resolution spectrograph (1.9-2.5 microns, R$\sim$35,000), we present the first dedicated radial velocity (RV) observations around a high-contrast, directly imaged substellar companion, GQ Lup B, to search for exo-satellites. Over 11 epochs, we find a best and median RV error of 400-1000 m/s, most likely limited by systematic fringing in the spectra due to transmissive optics within KPIC. With this RV precision, KPIC is sensitive to exomoons 0.6-2.8% the mass of GQ Lup B ($\sim 30 M_{\text{Jup}}$) at separations between the Roche limit and $65 R_{\text{Jup}}$, or the extent of the cavity inferred within the CPD detected around GQ Lup B. Using simulations of HISPEC, a high resolution infrared spectrograph planned to debut at W.M. Keck Observatory in 2026, we estimate future exomoon sensitivity to increase by over an order of magnitude, providing sensitivity to less massive satellites potentially formed within the CPD itself. Additionally, we run simulations to estimate the amount of material that different masses of satellites could clear in a CPD to create the observed cavity. We find satellite-to-planet mass ratios of $q > 2 \times 10^{-4}$ can create observable cavities and report a maximum cavity size of $\sim 51 \, R_{\text{Jup}}$ carved from a satellite.

We present the properties of two candidate massive ($M_\star\sim10^{11}M_\odot$) and dusty ($A_{\rm v}>2.5$ mag) galaxies at $z=5-7$ in the first 0.28 deg$^2$ of the COSMOS-Web survey. One object is spectroscopically confirmed at $z_{\rm spec}=5.051$, while the other has a robust $z_{\rm phot}=6.7\pm0.3$. Thanks to their extremely red colors ($F277W-F444W\sim1.7$ mag), these galaxies satisfy the nominal color-selection for the widely-studied ``little red dot" (LRD) population with the exception of their spatially-resolved morphologies. The morphology of our targets allows us to conclude that their red continuum is dominated by highly obscured stellar emission and not by reddened nuclear activity. Using a variety of SED-fitting tools and star formation histories, we estimate the stellar masses to be $\log(M_\star)=11.32^{+0.07}_{-0.15}$ $M_\odot$ and $\log(M_\star)=11.2^{+0.1}_{-0.2}$ $M_\odot$, respectively, with a red continuum emission dominated by a recent episode of star formation. We then compare their number density to the halo mass function to infer stellar baryon fractions of $\epsilon_\star\sim0.25$ and $\epsilon_\star\sim0.5$. Both are significantly higher than what is commonly observed in lower-z galaxies or more dust-obscured galaxies at similar redshifts. With very bright ultra-high-z Lyman-Break Galaxies and some non-AGN dominated LRDs, such ``extended" LRDs represent another population that may require very efficient star formation at early times.

Redshift-space distortions present a significant challenge in building models for the three-point correlation function (3PCF). We compare two possible lines of attack: the streaming model and standard perturbation theory (SPT). The two approaches differ in their treatment of the non-linear mapping from real to redshift space: SPT expands this mapping perturbatively, while the streaming model retains its non-linear form but relies on simplifying assumptions about the probability density function (PDF) of line-of-sight velocity differences between pairs or triplets of tracers. To assess the quality of the predictions and the validity of the assumptions of these models, we measure the monopole of the matter 3PCF and the first two moments of the pair- and triplewise velocity PDF from a suite of N-body simulations. We also evaluate the large-scale limit of the streaming model and determine under which conditions it aligns to SPT. On scales $>10\,h^{-1}\mathrm{Mpc}$, we find that the streaming model for the 3PCF monopole is dominated by the first two velocity moments, making the exact shape of the PDF irrelevant. This model can match the accuracy of a Stage-IV galaxy survey, if the velocity moments are measured directly from the simulations. However, replacing the measurements with perturbative expressions to leading order generates large errors already on scales of $60-70 h^{-1}\mathrm{Mpc}$. This is the main drawback of the streaming model. Conversely, the SPT model for the 3PCF cannot account for the significant velocity dispersion that is present at all scales, and consequently provides predictions with limited accuracy. We demonstrate that this issue can be addressed by isolating the large-scale limit of the dispersion, which leads to typical Fingers-of-God damping functions. Overall, the SPT model with a damping function provides the best deal in terms of accuracy and computing time.

We present the Big-Bang Nucleosynthesis (BBN) simulation with a bubble universe scenario around a rotating black hole (BH) in Kerr-AdS$_5$ spacetime to explain recently updated observations of light elements such as the primordial helium abundance. In this scenario, the geometry of the 4D- early Universe is described as a vacuum bubble that undergoes quasi-de Sitter expansion in Kerr- AdS$_5$ spacetime. We find that the BH mass and spin parameter, which show an anti-correlation against the total radiation, are important to resolve the ${}^4$He anomaly. The present results provide clues to finding a connection between the observed results of light-element nucleosynthesis and the scenario of the 4D-bubble universe in AdS$_5$ spacetimes

We present a new measurement of the dark and luminous matter distribution of massive elliptical galaxies, and their evolution with redshift, by combining strong lensing and dynamical observables. Our sample of 58 lens galaxies covers a redshift range of $0.090\leq z_{\rm l}\leq0.884$. By combining new Hubble Space Telescope imaging with previously observed velocity dispersion and line-of-sight measurements, we decompose the luminous matter profile from the dark matter profile and perform a Bayesian hierarchical analysis to constrain the population-level properties of both profiles. We find that the inner slope of the dark matter density profile ("cusp"; $\rho_{\rm DM}\propto r^{-\gamma_{\rm in}}$) is slightly steeper ($\mu_{\gamma_{\rm in}}=1.18^{+0.03}_{-0.03}$ at $z=0.35$ with $\leq0.16$ intrinsic scatter) than a standard Navarro$-$Frenk$-$White (NFW; $\gamma_{\rm in}=1$), with an appreciable evolution with redshift ($d\log(\gamma_{\rm in})/dz=-0.33\pm0.13$) and is consistent with NFW-like distributions at higher redshifts ($z\geq0.56$ for $\leq1\sigma$ consistency). Additionally, we find the stellar mass-to-light ratio at the population level consistent with that of a Salpeter initial mass function, a small stellar mass-to-light gradient ($\kappa_{*}(r)\propto r^{-\eta}$, with $\overline{\eta}\leq9.4\times10^{-3}$), and isotropic stellar orbits. Our averaged total mass density profile is consistent with a power-law profile within $0.25-4$ Einstein radii ($\overline{\gamma}=2.14\pm0.06$), with an internal mass-sheet transformation parameter $\overline{\lambda}=1.02\pm0.01$ consistent with no mass sheet. Our findings confirm the validity of the standard mass models used for time-delay cosmography. However, our results are in strong tension with predictions from hydrodynamical simulations such as IllustrisTNG, highlighting the need to better understand the formation of massive galaxies.

Over the past few years alone, the lensing community has discovered thousands of strong lens candidates, and spectroscopically confirmed hundreds of them. In this time of abundance, it becomes pragmatic to focus our time and resources on the few extraordinary systems, in order to most efficiently study the universe. In this paper, we present such a system: DESI-090.9854-35.9683, a cluster-scale lens at $z_{\rm l} = 0.49$, with seven observed lensed sources around the core, and additional lensed sources further out in the cluster. From the number and the textbook configuration of the lensed images, a tight constraint on the mass potential of the lens is possible. This would allow for detailed analysis on the dark and luminous matter content within galaxy clusters, as well as a probe into dark energy and high-redshift galaxies. We present our spatially resolved kinematic measurements of this system from the Very Large Telescope Multi Unit Spectroscopic Explorer, which confirm five of these source galaxies (in ascending order, at $z_{\rm s} = 0.962, 0.962, 1.166, 1.432,$ and $1.432$). With previous Hubble Space Telescope imaging in the F140W and F200LP bands, we also present a simple two power-law profile flux-based lens model that, for a cluster lens, well models the five lensed arc families with redshifts. We determine the mass to be $M(< \theta_{\rm E}) = 4.78\times10^{13} M_{\odot}$ for the primary mass potential. From the model, we extrapolate the redshift of one of the two source galaxies not yet spectroscopically confirmed to be at $z_{\rm s}=4.52^{+1.03}_{-0.71}$.

We present improved empirical density profiles of Uranus and interpret them in terms of their temperature and composition using a new random algorithm. The algorithm to determine the temperature and composition is agnostic with respect to the temperature gradient in non-isentropic regions and chooses randomly amongst all possible gradients that are stable against convection and correspond to an Equation of State compatible composition. Our empirical models are based on an efficient implementation of the Theory of Figures up to 10th order including a proper treatment of the atmosphere. The accuracy of 10th order ToF enables us to present accurate calculations of the gravitational moments of Uranus up to $J_{14}$: $J_{6} = ( 5.3078 \pm 0.3312)\cdot10^{-7}$, $J_{8} = (-1.1114 \pm 0.1391)\cdot10^{-8}$, $J_{10} = ( 2.8616 \pm 0.5466)\cdot10^{-10}$, $J_{12} = (-8.4684 \pm 2.0889)\cdot10^{-12}$ and $J_{14} = ( 2.7508 \pm 0.7944)\cdot10^{-13}$. We consider two interior models of Uranus that differ with respect to the maximal number of materials allowed per layer of Uranus (three vs. four composition components). The case with three materials does not allow Hydrogen and Helium in deeper parts of Uranus and results in a higher water abundance which leads to lower central temperatures. On the other hand, the models with four materials allow H-He to be mixed into the deeper interior and lead to rock-dominated solutions. We find that these four composition components models are less reliable due to the underlying empirical models incompatibility with realistic Brunt frequencies. Most of our models are found to be either purely convective with the exception of boundary layers, or only convective in the outermost region. Almost all of our models possess a region that is convective and consists of ionic H$_{2}$O which could explain the generation of Uranus' magnetic field.

Stellar limb darkening is the observed variation in brightness of a star between its centre and edge (or limb) when viewed in the plane of the sky. Stellar brightness is maximal at the centre and then decreases radially and monotonically towards the limb -- hence the term "limb darkening". This effect is crucial for finding and characterising planets beyond our Solar System, known as exoplanets, as these planets are often studied when crossing in front of their host stars. As such, limb darkening is directly linked to the exoplanet signals. Limb darkening is typically modelled by one of various functional forms, as outlined in Claret (2000) and Sing (2010), and the coefficients of these functions is what ExoTiC-LD is designed to compute. A wide variety of functional forms are supported, including those benchmarked by Espinoza & Jordán (2016) as well as reparameterisations suggested by Kipping (2013).

The Sun exhibits episodic surges of magnetic activity across a range of temporal and spatial scales, the most prominent of which is the 11-ish year modulation of sunspot production. Beside the ~170 (min to max) decadal variation in sunspot production there is a less-explored quasi-annual variation in the range of 25-50 sunspots/year in magnitude. In addition, there is there is a slower, ~80 year period, 10-50 variation in the sunspot number, that is commonly referred to as the 'Gleissberg Cycle.' Using a suite of contemporary and historical observations we will illustrate these elements of our star's episodic behavior and present a hypothesis that may provide a consistent physical link between the observed 'climatic', 'decadal' and 'seasonal' magnetic variation of our star.

Large spectroscopic surveys of individual massive stars, such as ULLYSES and XSHOOTU, provide observational data for hundreds of massive stars. Their analysis requires large numbers of synthetic spectra so that stellar parameters can be determined. In addition, libraries of massive stars' spectra are needed to produce population synthesis models able to reproduce the observed spectra of unresolved young stellar populations, such as those revealed by the James Webb Space Telescope (JWST) in the early Universe. Our main goal is to provide an extensive library of synthetic spectra and spectral energy distributions of OB stars at metallicities of the Magellanic Clouds. This library will offer a wealth of spectrophotometric information, making it readily applicable to a variety of astrophysical problems. We used the CMFGEN code to calculate 606 NLTE, line-blanketed, expanding atmosphere models using a comprehensive set of atomic data. An overall metallicity of 1/2 Z$_\odot$ and 1/5 Z$_\odot$ was adopted for the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC), respectively. We produced high-resolution spectra from 30 angstroms to 3 $\mu$m for stars on the Main Sequence and slightly beyond. We provide spectral energy distributions, normalized synthetic spectra, ionizing fluxes, and photometry in various bands: Johnson UBV, Cousins RI, Bessel JHK, selected wide JWST filters, Gaia, and LSST ugrizy filters. For each of these filters, we compute bolometric corrections for all synthetic spectra and calibrations as a function of effective temperature. All of our synthetic spectra are publicly available through the POLLUX database, aiming to expedite multiwavelength analyses of massive stars in low metallicity environments.

Measurements of the galaxy density and weak-lensing profiles of galaxy clusters typically rely on an assumed cluster center, which is taken to be the brightest cluster galaxy or other proxies for the true halo center. Departure of the assumed cluster center from the true halo center bias the resultant profile measurements, an effect known as miscentering bias. Currently, miscentering is typically modeled in stacked profiles of clusters with a two parameter model. We use an alternate approach in which the profiles of individual clusters are used with the corresponding likelihood computed using a Gaussian mixture model. We test the approach using halos and the corresponding subhalo profiles from the IllustrisTNG hydrodynamic simulations. We obtain significantly improved estimates of the miscentering parameters for both 3D and projected 2D profiles relevant for imaging surveys. We discuss applications to upcoming cosmological surveys.

It is common for surveys that are designed to find artificial signals generated by distant civilizations to focus on galactic sources. Recently, researchers have started focusing on searching for all other sources within the field observed, including the vast population of background galaxies. Toward a population of galaxies in the background toward the Vela supernova remnant, we search for technosignatures, spectral and temporal features consistent with our understanding of technology. We set transmitter power limits for the detection of signals in a population of over 1,300 galaxies within a single field of view observed with the Murchison Widefield Array.

We use a sample of 73 simulated satellite and central dwarf galaxies spanning a stellar mass range of $10^{5.3}-10^{9.1} M_\odot$ to investigate the origin of their stellar age gradients. We find that dwarf galaxies often form their stars "inside-out," i.e., the stars form at successively larger radii over time. However, the oldest stars get reshuffled beyond the star forming radius by fluctuations in the gravitational potential well caused by stellar feedback (the same mechanisms that cause dwarfs to form dark matter cores). The result is that many dwarfs appear to have an "outside-in" age gradient at $z=0$, with younger stellar populations more centrally concentrated. However, for the reshuffled galaxies with the most extended star formation, young stars can form out to the large radii to which the old stars have been reshuffled, erasing the age gradient. We find that major mergers do not play a significant role in setting the age gradients of dwarfs. We find similar age gradient trends in satellites and field dwarfs, suggesting environment plays only a minor role, if any. Finally, we find that the age gradient trends are imprinted on the galaxies at later times, suggesting that the stellar reshuffling dominates after the galaxies have formed 50% of their stellar mass. The later reshuffling is at odds with results from the FIRE-2 simulations. Hence, age gradients offer a test of current star formation and feedback models that can be probed via observations of resolved stellar populations.

It is now well established that galactic systems are inherently multiphase, and that understanding the roles and interactions of the various phases is key towards a more complete picture of galaxy formation and evolution. For example, these interactions play a pivotal role in the cycling of baryons which fuels star formation. It remains a challenge that the transport and dynamics of cold clouds in their surrounding hot environment are governed by complex small scale processes (such as the interplay of turbulence and radiative cooling) that determine how the phases exchange mass, momentum and energy. Large scale models thus require subgrid prescriptions in the form of models validated on small scale simulations, which can take the form of a system of coupled differential equations. In this work, we explore using neural ordinary differential equations which embed a neural network as a term in the subgrid model to capture an uncertain physical process. We then apply Symbolic Regression on the learned model to potentially discover new insights into the physics of cloud-environment interactions. We test this on both generated mock data and actual simulation data. We also extend the neural ODE to include a secondary neural term. We show that neural ODEs in tandem with Symbolic Regression can be used to enhance the accuracy and efficiency of subgrid models, and/or discover the underlying equations to improve generality and scientific understanding. We highlight the potential of this scientific machine learning approach as a natural extension to the traditional modelling paradigm, both for the development of semi-analytic models and for physically interpretable equation discovery in complex non-linear systems.

The ``2-process Model'' is a promising technique for interpreting stellar chemical abundance data from large-scale surveys (e.g., SDSS-IV/V, GALAH), enabling more quantitative empirical studies of differences in chemical enrichment history between galaxies without relying on detailed yield and evolution models. In this work, we fit 2-process model parameters to (1) a luminous giant Milky Way (MW) sample and (2) stars comprising the Sagittarius Dwarf Galaxy (Sgr). We then use these two sets of model parameters to predict the abundances of 14 elements of stars belonging to the MW and in five of its massive satellite galaxies, analyzing the residuals between the predicted and observed abundances. We find that the model fit to (1) results in large residuals (0.1-0.3 dex) for most metallicity-dependent elements in the metal-rich ([Mg/H] $>$ -0.8) stars of the satellite galaxies. However, the model fit to (2) results in small or no residuals for all elements across all satellite galaxies. Therefore, despite the wide variation in [X/Mg]-[Mg/H] abundance patterns of the satellite galaxies, the 2-process framework provides an accurate characterization of their abundance patterns across many elements, but these multi-element patterns are systematically different between the dwarf galaxy satellites and the MW disks. We consider a variety of scenarios for the origin of this difference, highlighting the possibility that a large inflow of pristine gas to the MW disk diluted the metallicity of star-forming gas without changing abundance ratios.

We present a deep X-Shooter rest-frame UV to optical spectral analysis of the heavily reddened quasar, ULASJ2315+043 at z=2.566, known to reside in a major-merger host galaxy. The rest-frame optical is best-fit by a dust-reddened quasar E(B-V)_QSO = 1.55 with black-hole mass log10(Hbeta, MBH [M_sol]) = 10.26 +\- 0.05, bolometric luminosity L_Bol = 10^48.16 erg s^-1 and Eddington-scaled accretion rate log10(\lambda_Edd) = -0.19. We find remarkable similarities between ULASJ2315+043 and the high-redshift Little Red Dots (LRDs). The rest-frame UV cannot be explained by a dusty quasar component alone and requires an additional blue component consistent with either a star-forming host galaxy or scattered AGN light. We detect broad high-ionisation emission lines in the rest-UV, supporting the scattered light interpretation for the UV excess. The scattering fraction represents just 0.05% of the total luminosity of ULASJ2315+043. Analysis of the mid infra-red SED suggests an absence of hot dust on torus-scales similar to what is observed for LRDs. The obscuring medium is therefore likely on galaxy scales. We detect narrow, blueshifted associated absorption line systems in CIV, NV, SiIV and SiIII. There is evidence for significant high-velocity (>1000 km s^-1) outflows in both the broad and narrow line regions as traced by CIV and [OIII] emission. The kinetic power of the [OIII] wind is e_ion = 10^44.61 erg s^-1 ~ 0.001 L_Bol. ULASJ2315+043 is likely in an important transition phase where star formation, black-hole accretion and multi-phase gas flows are simultaneously occurring.

We provide a detailed comparison between the ``gravoturbulent'' (GT) and ``global hierarchical collapse'' (GHC) models for molecular clouds and star formation, their respective interpretations of the observational data, the features they share, and suggested tests and observations to discern between them. Also, we clarify common misconceptions in recent literature about the global and hierarchical nature of the GHC scenario, and briefly discuss the evolution of some aspects of both models toward convergence. GT assumes that molecular clouds and their substructures are in approximate virial equilibrium and are in a near-stationary state, interprets the linewidth-derived nonthermal motions exclusively as turbulence, which provides additional pressure against self-gravity. Conversely, GHC assumes that most star-forming molecular clouds and their substructures are part of a continuous gravitationally-driven flow, each accreting from their parent structure. Thus, the clouds and their star formation rate evolve in time. GHC interprets nonthermal motions as a mixture of infall and turbulent components, with the relative importance of the former increasing as the objects become denser and/or more massive. Tests that may provide clues to distinguishing between GT and GHC must take into account that the innermost parts of globally gravitationally bound structures may not locally appear bound, and thus the binding may have to be searched for at the largest scale of the structure.

We utilized steady-state, axisymmetric, viscous hydrodynamic fluid equations around a black hole in a Schwarzschild geometry background. Here, the relativistic Schwarzschild geometry is mimicked by the Paczy{ń}sky-Wiita potential. We investigated two types of inflowing gases that can generate different kinds of accretion flows around the central objects. The inflowing gases are presented on the local energies ($B_{ob}$) of the gases versus the outermost accretion boundary locations ($r_{ob}$) plane we named it the outermost boundary condition (OBC)-plane. Based on the energies of the inflowing gases we found two types of inflowing gas classified as cold-mode and hot-mode inflowing gases in the OBC-plane. Doing so we have found the initial temperature of the inflowing gases can be a parameter for the study of the accretion process. As it can affect the disk structure and optical depth of the accretion flow, which in turn can impact the radiative emissions observed in many accreting sources.

In this work, we constrain the values of the parameters of the Generalized Tolman-Oppenheimer-Volkoff (GTOV) equation through Bayesian inference. We use the mass and radius data from the Neutron Star Interior Composition Explorer (NICER) for PSR J0740+6620 and PSR J0030+0451, as well as the mass, radius, and dimensionless tidal deformability from the gravitational wave (GW) events GW190814 and GW170817. We use two distinct parameterizations of the extended non-linear Walecka model (eNLW) with and without hyperons. The GTOV employed for the study contains additional free parameters with different physical motivations. Two possible scenarios are considered in our analysis: conservative and speculative. In the first case, we take into account the most reliable neutron star (NS) data from NICER and the GW170817 event. In the second case, we consider the possibility that the compact object with a mass of $2.54 M_{\odot}$ in the GW190814 event is an NS. Our findings show significant improvements in the physical quantities analyzed, leading to better agreement with the observational data compared to the results obtained using the TOV equation.

SPIDER is a balloon-borne instrument designed to map the cosmic microwave background at degree-angular scales in the presence of Galactic foregrounds. SPIDER has mapped a large sky area in the Southern Hemisphere using more than 2000 transition-edge sensors (TESs) during two NASA Long Duration Balloon flights above the Antarctic continent. During its first flight in January 2015, SPIDER observed in the 95 GHz and 150 GHz frequency bands, setting constraints on the B-mode signature of primordial gravitational waves. Its second flight in the 2022-23 season added new receivers at 280 GHz, each using an array of TESs coupled to the sky through feedhorns formed from stacks of silicon wafers. These receivers are optimized to produce deep maps of polarized Galactic dust emission over a large sky area, providing a unique data set with lasting value to the field. In this work, we describe the instrument's performance during SPIDER's second flight.

Recent observations by Parker Solar Probe (PSP) suggest that protons and heavier ions are accelerated to high energies by magnetic reconnection at the heliospheric current sheet (HCS). By solving the energetic particle transport equation in large-scale MHD simulations, we study the compression acceleration of protons and heavier ions in the reconnecting HCS. We find that the acceleration of multi-species ions results in nonthermal power-law distributions with spectral index consistent with the PSP observations. Our study shows that the high-energy cutoff of protons can reach $E_{max} \sim 0.1$ - $1$ MeV depending on the particle diffusion coefficients. We also study how the high-energy cutoff of different ion species scales with the charge-to-mass ratio $E_{max} \propto (Q/M)^\alpha$. When determining the diffusion coefficients from the quasilinear theory with a Kolmogorov magnetic power spectrum, we find that $\alpha \sim 0.4$, which is somewhat smaller than $\alpha \sim 0.7$ observed by PSP.

Combining Chandra, ALMA, EVLA, and Hubble Space Telescope archival data and newly acquired APO/DIS spectroscopy, we detect a double-lobed 17~kpc X-ray emission with plumes oriented approximately perpendicular and parallel to the galactic plane of the massive lenticular galaxy NGC\,5084 at 0.3--2.0~keV. We detect a highly inclined ($i=71.2^{+1.8\circ}_{-1.7}$), molecular circumnuclear disk ($D=304^{+10}_{-11}$ pc) in the core of the galaxy rotating (V$^{\rm (2-1) CO}_{\rm rot}=242.7^{+9.6}_{-6.4}$ km s$^{-1}$) in a direction perpendicular to that of the galactic disk, implying a total mass of $\log_{10}\left( \frac{M_{\rm BH}}{M_{\odot}} \right) = 7.66^{+0.21}_{-0.15}$ for NGC\,5084's supermassive black hole. Archival EVLA radio observations at 6 cm and 20 cm reveal two symmetric radio lobes aligned with the galactic plane, extending to a distance of $\overline{R}=4.6\pm0.6$ kpc from the core, oriented with the polar axis of the circumnuclear disk. The spectral energy distribution lacks strong emission lines in the optical range. Three formation scenarios are considered to explain these multi-wavelength archival observations: 1) AGN re-orientation caused by accretion of surrounding material, 2) AGN-driven hot gas outflow directed along the galactic minor axis, or 3) a starburst / supernovae driven outflow at the core of the galaxy. This discovery is enabled by new imaging analysis tools including \SAUNAS\ (Selective Amplification of Ultra Noisy Astronomical Signal), demonstrating the abundance of information still to be exploited in the vast and growing astronomical archives.

Measuring the strength of three dimensional (3D) magnetic field vector is challenging as it is not easy to recognize whether its line-of-sight (LOS) and plane-of-sky (POS) components are obtained from the same region. CN ($N = 1 - 0$) emission has been used to get the LOS component of a magnetic field (B$_\mathrm{LOS}$) from its Zeeman splitting lines, while dust continuum emission has been used to get the POS component of a magnetic field (B$_\mathrm{POS}$). We use the CN ($N = 1 - 0$) data observed with the Taeduk Radio Astronomy Observatory (TRAO) 14-m telescope and the dust continuum data from $Herschel$ archive toward six high-mass star-forming regions in order to test whether CN line and dust continuum emission can trace a similar region and thus can be used for inferring 3D magnetic field strength. Our comparison between CN and H$_2$ column densities for all targets indicates that CN line emission tends to be strong toward bright continuum regions. The positions of peak CN column densities are particularly well correlated with those of peak H$_2$ column densities at least over the H$_2$ column density of 8.0 $\times$ 10$^{22}$ cm$^{-2}$ within one or two telescope beam size in all targets, implying that CN line and dust continuum emitting regions are likely spatially coincident. This enabled us to make the reliable measurement of 3D magnetic field strengths of five targets by taking a vector sum of their B$_\mathrm{LOS}$ and B$_\mathrm{POS}$, helping to decide the magnetical criticality of the targets as supercritical or transcritical.

In the last decade, there have been several discoveries of Active Galactic Nuclei (AGN) in dwarf galaxies including an AGN in an ultra-compact dwarf galaxy with a Black Hole mass $>$10$^{6}$ M$_{\odot}$. However, finding a Supermassive Black Hole (SMBH) in a dwarf Low Surface Brightness (LSB) galaxy is rare. We report the discovery of a Seyfert type-2 class AGN which is associated with a nuclear SMBH of mass $\sim$6.5 $\times$ 10$^{6}$ M$_{\odot}$ in a dwarf LSB galaxy ($\mu_{0,r}$ $>$ 23.8 mag/arcsec$^{2}$) that we denote by MJ0818+2257. The galaxy was previously thought to be an outlying emission blob around the large spiral galaxy LEDA 1678924. In our current analysis, which includes the detection of the optical counterpart of MJ0818+2257, we study its ionized gas kinematics and find that the dynamical mass within the ionized gas disk is $\sim$5.3 $\times$ 10$^{9}$ M$_{\odot}$. This is comparable to its stellar mass which is $\sim$3$\times$ 10$^{9}$ M$_{\odot}$ and suggests that MJ0818+2257 is moderately dark matter-dominated within the stellar disk. The SMBH mass to galaxy stellar mass ratio is $M_{BH}/M(*)>0.022$ which is high compared to disk galaxies. Our detection of a SMBH in a bulgeless LSB dwarf galaxy raises questions about the growth of SMBHs in low-luminosity galaxies and suggests the possibility of detecting heavy, seed black holes from early epochs in LSB dwarf galaxies in the low redshift universe.

The basic premise of using HII starburst galaxies (HIIGs) as cosmic "standard candels" is that there is a significant correlation between the H$\beta$ luminosity ($L$) and the velocity dispersion ($\sigma$) of the ionized gas from HIIGs measurements, which can be called as the empirical $L$ - $\sigma$ relation. However, the scaling $L$ - $\sigma$ relation well-calibrated with the lower-redshift HIIGs is unfitted for the higher-redshift HIIGs. To solve this problem, we explore new relational expression for the $L$ - $\sigma$ relation which should be suitable for both lower-redshift and higher-redshift HIIGs. After reconstructing the Hubble diagram with the Gaussian process (GP) method from the Pantheon+ supernovae Ia sample, we examine and compare six different revised formulas of $L$ - $\sigma$ relation. Furthermore, we use the Bayesian evidence to compare the revised $L$ - $\sigma$ relations with the analysis of a joint sample of 36 giant extragalactic HII regions (GEHRs) and 145 HIIGs. It turns out that the redshift-dependent bilinear correction and the quadratic $\sigma$ based correction are significantly better than the others. Moreover, a quadratic $\sigma$ based correction is the most supported one. It suggests that the appropriate corrections to the $L$ - $\sigma$ relation should be considered when the HIIGs are used as a kind of cosmological probes.

We collected more than 300 high-resolution spectra of the 300 Myr old star BD+40 2790 (TOI-2076) over ~3 years. This star hosts three transiting planets discovered by TESS, with orbital periods ~10, 21, and 35 days. BD+40 2790 shows an activity-induced scatter larger than 30 m/s in the radial velocities. We employed different methods to measure the stellar radial velocities and several models to filter out the dominant stellar activity signal, in order to bring to light the planet-induced signals which are expected to have semi-amplitudes one order of magnitude lower. We evaluated the mass loss rate of the planetary atmospheres using photoionization hydrodynamic modeling. The dynamical analysis confirms that the three sub-Neptune-sized companions (our radius measurements are $R_b$=2.54$\pm$0.04, $R_c$=3.35$\pm$0.05, and $R_d$=3.29$\pm$0.06 $R_{\rm Earth}$) have masses in the planetary regime. We derive 3$\sigma$ upper limits below or close to the mass of Neptune for all the planets: 11--12, 12--13.5, and 14--19 $M_{\rm Earth}$ for planet $b$, $c$, and $d$ respectively. In the case of planet $d$, we found promising clues that the mass could be between ~7 and 8 $M_{\rm Earth}$, with a significance level between 2.3--2.5$\sigma$ (at best). This result must be further investigated using other analysis methods or using high-precision near-IR spectrographs to collect new radial velocities, which could be less affected by stellar activity. Atmospheric photo-evaporation simulations predict that BD+40~2790 b is currently losing its H-He gaseous envelope, which will be completely lost at an age within 0.5--3 Gyr if its current mass is lower than 12 $M_{\rm Earth}$. BD+40 2790 c could have a lower bulk density than $b$, and it could retain its atmosphere up to an age of 5 Gyr. For the outermost planet $d$, we predict almost negligible evolution of its mass and radius induced by photo-evaporation.

Rings are complex structures surrounding giant planets and some minor bodies in the Solar System. While some formation mechanisms could also potentially foster their existence around (regular or irregular) satellites, none of these bodies currently bear these structures. We aim to understand the underlying mechanisms that govern the potential formation, stability, and/or decay of hypothetical circumsatellital rings (CSRs), orbiting the largest moons in the Solar System. This extends to the exploration of short-term morphological features within these rings, providing insights into the ring survival time-scales and the interactions that drive their evolution. To conduct this study, we use numerical N-body simulations under the perturbing influence of the host planet and other moon companions. We found that moons with a lower Roche-to-Hill radius can preserve their rings over extended periods. Moreover, the gravitational environment in which these rings are immersed influences the system's morphological evolution, inducing gaps through the excitation of eccentricity and inclination of constituent particles. Specifically, our results show that Iapetus' and Rhea's rings experience minimal variations in their orbital parameters, enhancing their long-term stability. This agrees with the hypothesis that some of the features of Iapetus and Rhea were produced by ancient ring systems, for example, the huge ridge in Iapetus equator as a result of a decaying ring. From a dynamical perspective, we found that there are no mechanisms that preclude the existence of CSRs and we attribute their current absence to non-gravitational phenomena. Effects such as stellar radiation, magnetic fields, and the influence of magnetospheric plasma can significantly impact the dynamics of constituent particles and trigger their decay, highlighing the importance of future studies on these effects.

Knowing the kind of remnant produced after the merger of a binary neutron star system, e.g., if a black hole forms or not, would not only shed light on the equation of state describing the extremely dense matter inside neutron stars, but also help understand the physical processes involved in the postmerger phase. Moreover, in the event of a gravitational-wave detection, predicting the presence of a neutron star remnant is crucial in order to advise potential electromagnetic follow-up campaigns. In this work, we use Gradient Boosted Decision Trees and publicly available data from numerical-relativity simulations to construct a classifier that predicts the outcome of binary neutron star mergers, based on the binary's parameters inferred from gravitational-wave inspiral signals: total mass, mass-weighted tidal deformability, mass ratio, and effective inspiral spin. Employing parameters that can be estimated from the inspiral part of the signal only allows us to predict the remnant independently on the detection of a postmerger gravitational-wave signal. We build three different classifiers to distinguish between various potential scenarios, we estimate their accuracy and the confidence of their predictions. Finally, we apply the developed classifiers to real events data, finding that GW170817 most likely lead to the formation of a hypermassive neutron star, while GW190425 to a prompt collapse to a black hole.

Persistent tensions in the $\Lambda$CDM cosmological model underline the importance of tests of its basic assumptions. One such potential test arises from the fact that the surface of zero expansion around the collapsing object with spherical symmetry is strictly related to the object's mass and the value of the cosmological constant. We propose a complementary probe relating the averaged zero-expansion volume to the mass and the background cosmological Hubble parameter. Using the relativistic Zel'dovich approximation we are able to relax the spherical symmetry assumption and hence obtain a more general test of cosmological dynamics. Alternatively, our method can serve as a test of compatibility of relativistic N-body simulations and the scalar, averaged Einstein's equations with the relativistic Zel'dovich approximation serving as a closure condition.

High-resolution spectroscopy in soft X-rays ($<2$ keV) requires diffractive elements to resolve any astrophysically relevant diagnostics, such as closely spaced lines, weak absorption lines, or line profiles. The Rowland torus geometry describes how gratings and detectors need to be positioned to optimize the spectral resolving power. We describe how an on-axis Rowland geometry can be tilted to accommodate blazed gratings. In this geometry, two channels with separate optical axes can share the same detectors (double tilted Rowland spectrograph, DTRS). Small offsets between the channels can mitigate the effect of chip gaps and reduce the alignment requirements during the construction of the instrument. The DTRS concept is especially useful for sub-apertured mirrors, because it allows an effective use of space in the entrance aperture of a spacecraft. One mission that applies this concept is the Arcus Probe.

In this study, we present an analysis of the standard flat-$\Lambda$CDM model using a cosmographic approach, incorporating recent DESI BAO observations and Supernovae Type Ia catalogues (SNIa), including the DES-SN5YR and Pantheon+ compilations. We find full consistency between the standard model and the cosmographic approach when considering DESI BAO and SNIa catalogues independently. When combining DESI BAO with SNIa data, we examine the impact of the Planck prior on the sound horizon at the drag epoch, $r_d$, and the Cepheid prior on the absolute magnitude, $M$. Applying the Planck prior on $r_d$ alone yields an $H_0$ value consistent with the Planck measurement, while applying the Cepheid prior on $M$ alone results in an $H_0$ value consistent with the SH0ES measurement. Without any priors, the $H_0$ value obtained has a large error margin, reconciling the Planck and SH0ES measurements. In all cases where individual priors are applied, we observe no significant tension between the flat-$\Lambda$CDM model and the cosmographic approach. However, when both Planck and Cepheid priors are applied simultaneously, significant tensions arise between the model and cosmography. This tension is even more pronounced when excluding LRG1 and LRG2 from the DESI measurements. These results suggest that the standard model cannot simultaneously align with both high-redshift Planck CMB observations and local Cepheid measurements.

Several correlations among Gamma-Ray Bursts (GRBs) quantities, both in the prompt and afterglow emissions, have been established during the last decades, thus enabling the standardization of GRBs as cosmological probes. Since GRBs are observed up to redshift $z \sim 9$, they represent a valuable tool to fill in the gap of information on the Universe evolution between the farthest type Ia supernovae and the Cosmic Microwave Background Radiation and to shed new light on the current challenging cosmological tensions. Without claiming for completeness, here we describe the state of the art of GRB correlations, their theoretical interpretations, and their cosmological applications both as standalone probes and in combination with other probes. In this framework, we pinpoint the importance of correcting the correlations for selection biases and redshift evolution to derive intrinsic relations, the assets of combining probes at different scales, and the need for the employment of the appropriate cosmological likelihood to precisely constrain cosmological parameters. Furthermore, we emphasize the benefits of the cosmographic approach to avoid any cosmological assumptions and the valuable applications of machine learning techniques to reconstruct GRB light curves and predict unknown GRB redshifts. Finally, we stress the relevance of all these factors, along with future observations, to definitely boost the power of GRBs in cosmology.

The cellular structure is considered to be a key as a criterion in initiation, propagation, and quenching of terrestrial detonation. While a few studies on type Ia supernovae, which are known to involve detonation, have addressed the importance of the cellular structure, further detailed treatment will benefit enhanced understanding of the explosion outcomes. In the present study, we bridge this gap in the astrophysics and engineering fields, focusing on the detonation in a heliumrich white dwarf envelope as the triggering process for the so-called double-detonation model. The cellular structures are quantified via high-resolution two-dimensional simulations. We demonstrate that widely-accepted terrestrial-experimental criteria for quenching and initiation of detonation can indeed explain the results of previous hydrodynamic simulations very well. The present study highlights the potential of continuing to apply the insight from terrestrial detonation experiments to astrophysical problems, specifically the long unresolved problem of the explosion mechanism of type Ia supernovae.

It is not straightforward to physically interpret the apparent morphology of galaxies. Recent observations by James Webb Space Telescope (JWST) revealed a dominant galaxy population at high redshifts ($z>2$) that were visually classified as discs for their flattened shapes and/or exponential light profiles. The extensively accepted interpretation is that they are dynamically cold discs supported by bulk rotation. However, it is long known that flattened shapes and exponential profiles are not exclusive for rotating disc structure. To break degeneracy and assess the rotational support of typical high-$z$ galaxies in the JWST samples, those with active star formation and stellar masses $\mathrm{lg}(\mathcal{M}_{\star}/\mathcal{M}_{\odot})\sim9$, we study the kinematics of their equal-mass counterparts at $z=0$. While these local star-forming low-mass galaxies are photometrically similar to real dynamically cold discs, they are not supported by ordered rotation but primarily by random motion, and their flattened shapes result largely from tangential orbital anisotropy. Given the empirical and theoretical evidence that young galaxies are dynamically hotter at higher redshifts, our results suggest that the high-$z$ JWST galaxies may not be cold discs but are dynamically warm/hot galaxies with flattened shapes driven by anisotropy. While both having low rotational support, local low-mass galaxies possess oblate shapes, contrasting the prolate shapes (i.e. cigar-like) of low-mass systems at high redshifts. Such shape transition (prolate$\Rightarrow$oblate) indicates an associated change in orbital anisotropy (radial$\Rightarrow$tangential), with roots likely in the assembly of their host dark matter halos.

Traditional models of coronal oscillations rely on modelling the coronal structures that support them as compact cylindrical waveguides. Recently, an alternative model of the structure of the corona has been proposed, where the thin strand-like coronal loops observable in the EUV emission are a result of line-of-sight integration of warps in more complex coronal structures, referred to as the coronal veil model. We extend the implications of the coronal veil model of the solar corona to models of coronal oscillations. Using the convection-zone-to-corona simulations with the radiation-magnetohydrodynamics code Bifrost, we analysed the structure of the self-consistently formed simulated corona. We focus on the spatial variability of the volumetric emissivity of the Fe IX 171.073 Å EUV line, and on the variability of the Alfvén speed, which captures the density and magnetic structuring of the simulated corona. We traced features associated with large magnitudes of the Alfvén speed gradient, which are the most likely to trap MHD waves and act as coronal waveguides, and looked for the correspondence with emitting regions which appear as strand-like loops in line-of-sight-integrated EUV emission. The waveguide filling factors corresponding to the fraction of the waveguides filled with plasma emitting in the given EUV wavelength range from 0.09 to 0.44. This suggests that we can observe only a small fraction of the waveguide. Similarly, the projected waveguide widths in the plane of the sky are several times larger than the widths of the apparent loops observable in EUV. We conclude that the 'coronal veil' structure is model-independent. As a result, we find a lack of straightforward correspondence between a peak in the integrated emission profile which constitutes an apparent coronal loop and regions of plasma bound by a large Alfvén speed gradient acting as waveguides.

To study the ejecta property dependence of the gamma-ray burst (GRB) afterglow, we carry out spherically symmetrical one-dimensional special relativistic magneto-hydrodynamic simulations of magnetized outflows with an adaptive mesh refinement method. The Lorentz factor evolutions of forward and reverse shocks induced by the interaction between magnetized ejecta and an ambient medium are investigated for a wide range of magnetization and width of the ejecta. The forward shock evolution is described by the magnetic acceleration, coasting, transition, and self-similar deceleration phases. According to our simulation results, we numerically calculate the corresponding radiation. Based on our numerical results, to model afterglow light curves in general cases, we construct semi-analytical formulae for the Lorentz factor evolutions. The magnetization and ejecta width dependence are clearly seen in the reverse shock light curves. The transition phase with a reasonable ejecta width can reproduce the shallow decay phase in the observed GRB afterglow. The inverse Compton emission in the magnetic acceleration phase can be responsible for the very steep rise of the early TeV emission in GRB221009A.

We present the results of a molecular survey of long period comets C/2021 A1 (Leonard) and C/2022 E3 (ZTF). Comet C/2021 A1 was observed with the IRAM 30-m radio telescope in November-December 2021 before perihelion when it was closest to the Earth. We observed C/2022 E3 in January-February 2023 with the Odin 1-m space telescope and IRAM 30-m, shortly after its perihelion, and when it was closest to the Earth. Snapshots were obtained during 12-16 November 2021 period for comet C/2021 A1. Spectral surveys were undertaken over the 8-13 December 2021 period for comet C/2021 A1 (8, 16, and 61 GHz bandwidth in the 3 mm, 2 mm, and 1 mm window) and over the 3-7 February 2023 period for comet C/2022 E3 (25 and 61 GHz at 2 and 1mm). We report detections of 14 molecular species (HCN, HNC, CH3CN, HNCO, NH2CHO, CH3OH, H2CO, HCOOH, CH3CHO, H2S, CS, OCS, C2H5OH and aGg-(CH2OH)2 ) in both comets plus HC3N and CH2OHCHO marginally detected in C/2021 A1 and CO and H2O (with Odin detected in C/2022 E3. The spatial distribution of several species is investigated. Significant upper limits on the abundances of other molecules and isotopic ratios are also presented. The activity of comet C/2021 A1 did not vary significantly between 13 November and 13 December 2021. Short-term variability in the outgassing of comet C/2022 E3 on the order of +-20% is present and possibly linked to its 8h rotation period. Both comets exhibit rather low abundances relative to water for volatiles species such as CO (< 2%) and H2S (0.15%). Methanol is also rather depleted in comet C/2021 A1 (0.9%). Following their revised photo-destruction rates, HNCO and HCOOH abundances in comets have been reevaluated. Both molecules are relatively enriched in these two comets (0.2% relative to water). We cannot exclude that these species could be produced by the dissociation of ammonium salts.

Gravitational waves (GWs) from gravitational three-body decay (graviton Bremsstrahlung process) can leave an indelible signal at ultrahigh frequencies. We focus on a scenario where superheavy particles are produced gravitationally at a transition between the inflationary and kination phases and analyze the detectability of the signal in the presence of GWs generated from the vacuum fluctuations during inflation. We find that, in many cases, GWs from the graviton Bremsstrahlung are buried in the stochastic gravitational wave background originating from inflation. However, if the superheavy particles are as heavy as the Planck scale, the graviton Bremsstrahlung can produce a sizable amount of GWs, surpassing the inflationary ones.

The measurement of atmospheric parameters is fundamental for scientific research using stellar spectra. The Chinese Space Station Telescope (CSST), scheduled to be launched in 2024, will provide researchers with hundreds of millions of slitless spectra for stars during a 10 yr survey. And machine learning has unparalleled efficiency in processing large amounts of data compared to manual processing. Here we studied the stellar parameters of early-type stars (effective temperature Teff more than 15,000 K) based on the design indicators of the CSST slitless spectrum and the machine learning algorithm, Stellar LAbel Machine. We used the Potsdam Wolf-Rayet (POWR) synthetic spectra library for cross validation. Then we tested the reliability of machine learning results by using the Next Generation Spectrum Library (NGSL) from Hubble Space Telescope observation data. We use the spectra with the impact of interstellar extinction (AV = 0, 0.5, 1, 1.5, 2 mag) and radial velocity (RV = -50, -30, 0, 30, 50 km s-1) from the POWR library as the test set. When RV = 0 km s-1 and AV = 0 mag, the average value and standard deviation for 3 wavelength ranges (2550-4050 Ang (R = 287); 4050-6300 Ang (R = 232); 6300-10000 Ang (R = 207)) are -66 K, 550 K, and 356 K for Teff, and 0.004 c.g.s, -0.024 c.g.s, and 0.01 c.g.s for log g. When using the observed data from NGSL as the testing samples, the deviation of Teff is less than 5%, and the deviation of log g is less than 11%. In addition, we also test the influence of shifting of spectra on the parameters accuracy. The deviation of Teff for the case with a shift of 5 Ang and 10 Ang are 3.6% and 4.3%, respectively; the deviation of log g are 4.2% and 5.1%. These results demonstrate that we can obtain relatively accurate stellar parameters of a population of early-type stars with the CSST slitless spectra and a machine-learning method.

Context: On 2022 May 4, an M5.7 flare erupted in the active region NOAA 13004, which was the target of a coordinated campaign between GREGOR, IRIS, Hinode, and ground-based instruments at the Ondřejov observatory. A flare kernel located at the edge of a pore was co-observed by the IRIS slit and GREGOR HiFI+ imagers. Aims: We investigated the flare continuum enhancement at different wavelength ranges in order to derive the temperature of the chromospheric layer heated during the flare. Methods: All datasets were aligned to IRIS slit-jaw images. We selected a pixel along the IRIS slit where the flare kernel was captured and evaluated multi-wavelength light curves within it. We defined a narrow IRIS near-UV band that comprises only continuum emission. The method, which assumes that the flare continuum enhancement is due to optically thin emission from hydrogen recombination processes, was applied to obtain a lower limit on the temperature in the layer where the continuum enhancement was formed. Results: We determined a lower limit for the temperature and its time evolution in the chromospheric layer heated during the flare in the range of (3-15).10^3 K. The mean electron density in that layer was estimated to be about 1.10^(13) cm^(-3). Conclusions: Multi-wavelength flare co-observations are a rich source of diagnostics. Due to the rapidly evolving nature of flares, the sit-and-stare mode is key to achieving a high temporal cadence that allows one to thoroughly analyse the same flare structure.

Recent observational constraints on the internal structure of Jupiter and Saturn suggest that these planets have ``fuzzy" cores, i.e., radial gradients of the concentration of heavy elements that might span $50\%$ to $70\%$ of each planet's radius. These cores could be composed of a semi-convective staircase, i.e., multiple convective layers separated by diffusive interfaces arising from double-diffusive instabilities. However, to date, no study has demonstrated how such staircases can avoid layer mergers and persist over evolutionary time scales. In fact, previous work has found that these mergers occur rapidly, quickly leading to only a single convective layer. Using 3D simulations of convective staircases in non-rotating and rotating flows, we demonstrate that rotation prolongs the lifetime of a convective staircase by increasing the timescale for both layer merger and erosion of the interface between the final two layers. We present an analytic model for the erosion phase, predicting that rotation increases the erosion time by a factor of approximately $\mathrm{Ro}^{-1/2}$, where $\mathrm{Ro}$ is the Rossby number of the convective flows (the ratio of the rotation period to the convective turnover time). For Jovian conditions at early times after formation (when convection is vigorous enough to mix a large fraction of the planet), we find the erosion time to be roughly $10^{9}~\mathrm{yrs}$ in the non-rotating case and $10^{11}~\mathrm{yrs}$ in the rotating case. Thus, the current existence of convective staircases within the deep interiors of giant planets is a strong possibility, and rotation could be an important factor in the preservation of their fuzzy cores.

Many super-Earths are on very short orbits around their host star and, therefore, more likely to be tidally locked. Because this locking can lead to a strong contrast between the dayside and nightside surface temperatures, these super-Earths could exhibit mantle convection patterns and tectonics that could differ significantly from those observed in the present-day solar system. The presence of an atmosphere, however, would allow transport of heat from the dayside towards the nightside and thereby reduce the surface temperature contrast between the two hemispheres. On rocky planets, atmospheric and geodynamic regimes are closely linked, which directly connects the question of atmospheric thickness to the potential interior dynamics of the planet. Here, we study the interior dynamics of super-Earth GJ 486b ($R=1.34$ $R_{\oplus}$, $M=3.0$ $M_{\oplus}$, T$_\mathrm{eq}\approx700$ K), which is one of the most suitable M-dwarf super-Earth candidates for retaining an atmosphere produced by degassing from the mantle and magma ocean. We investigate how the geodynamic regime of GJ 486b is influenced by different surface temperature contrasts by varying possible atmospheric circulation regimes. We also investigate how the strength of the lithosphere affects the convection pattern. We find that hemispheric tectonics, the surface expression of degree-1 convection with downwellings forming on one hemisphere and upwelling material rising on the opposite hemisphere, is a consequence of the strong lithosphere rather than surface temperature contrast. Anchored hemispheric tectonics, where downwellings und upwellings have a preferred (day/night) hemisphere, is favoured for strong temperature contrasts between the dayside and nightside and higher surface temperatures.

Due to strong irradiation, hot rocky exoplanets are able to sustain lava oceans. Direct interaction between these oceans and overlying atmospheres can provide insight into planetary interiors. In order to fully understand how the composition of the atmosphere of such planets are affected by the properties of the oceans, comprehensive chemical equilibrium models are required. Thus far, most models have only taken non-volatile species into account when calculating lava vaporisation. We investigate the effect of including C-, H-, N-, S-, and P-bearing species in the equilibrium lava vaporisation calculations on the overall atmospheric composition of hot rocky exoplanets by expanding our LavAtmos code. In LavAtmos 2.0 we integrate the chemical equilibrium code FastChem to expand the considered gas phase species to 523. We apply this new approach to calculate the composition of "pure" atmospheres which contain only a single volatile element and more complex atmospheres which contain C, H, N, S, and P. We also test two proposed compositions for the atmosphere of 55-Cnc e. We find that the inclusion of volatile elements in vaporisation calculations increases the partial pressures of vaporised species for all tested atmospheric compositions. Our models indicate that the tested volatile atmospheres above a lava ocean have a relatively low C-O ratio. This demonstrates the utility of complex chemical models that better describe the chemical behavior of atmospheres across a wide range of pressures and temperatures. Volatile elements must be taken into account for comprehensive modeling of vaporisation from a surface lava ocean into a volatile atmosphere. Vaporised species such as SiO, TiO, and Na may be present in greater abundances than previously estimated. A low atmospheric C/O ratio may be able to function as a new tracer for the presence of surface lava oceans on hot rocky exoplanets.

The forthcoming generation of radio telescope arrays promises significant advancements in sensitivity and resolution, enabling the identification and characterization of many new faint and diffuse radio sources. Conventional manual cataloging methodologies are anticipated to be insufficient to exploit the capabilities of new radio surveys. Radio interferometric images of diffuse sources present a challenge for image segmentation tasks due to noise, artifacts, and embedded radio sources. In response to these challenges, we introduce Radio U-Net, a fully convolutional neural network based on the U-Net architecture. Radio U-Net is designed to detect faint and extended sources in radio surveys, such as radio halos, relics, and cosmic web filaments. Radio U-Net was trained on synthetic radio observations built upon cosmological simulations and then tested on a sample of galaxy clusters, where the detection of cluster diffuse radio sources relied on customized data reduction and visual inspection of LOFAR Two Metre Sky Survey (LoTSS) data. The 83% of clusters exhibiting diffuse radio emission were accurately identified, and the segmentation successfully recovered the morphology of the sources even in low-quality images. In a test sample comprising 246 galaxy clusters, we achieved a 73% accuracy rate in distinguishing between clusters with and without diffuse radio emission. Our results establish the applicability of Radio U-Net to extensive radio survey datasets, probing its efficiency on cutting-edge high-performance computing systems. This approach represents an advancement in optimizing the exploitation of forthcoming large radio surveys for scientific exploration.

We investigate the ability of a simultaneous fitting of comet 67P/Churyumov-Gerasimenko's non-gravitational forces, torques and total water-outgassing rate, as observed by Rosetta, to constrain complex thermophysical models of cometary material. We extend the previous work of fitting geographically defined surface outgassing models to the Rosetta observations by testing the effects of a more detailed geomorphological mapping, the resolution of the shape-model used, self-heating by neighbouring facets on the shape-model, thermal inertia in the outgassing solution, and variation in the momentum coupling between the gas and the nucleus. We also directly compare the non-gravitational acceleration curves available in the literature. We correct an error in the calculation of pole-orientation in the previous paper. We find that, under the assumptions of the model: non-gravitational forces and torques are driven by water sublimation from the nucleus, thermal inertia and self-heating have only minor effects, spatially uniform activity cannot explain 67P's non-gravitational dynamics, spatially uniform momentum transfer cannot explain 67P's non-gravitational dynamics, and different terrain types have different instantaneous responses to insolation. Consolidated terrain facing south on 67P/Churyumov-Gerasimenko has a high outgassing flux, steep response to insolation, and large gas momentum transfer coefficient. Meanwhile, that facing north behaves differently, producing low-to-no water outgassing, and with a lower momentum transfer efficiency. Dusty terrain also has a lower outgassing rate and momentum transfer efficiency, and either depletes its volatile component or is buried in fall-back as the comet approaches the Sun. Momentum transfer appears correlated with insolation, likely due to an increased enhancement in the gas temperature as the dust it flows through is heated.

The cores of pulsars are expected to become superconducting soon after birth. The transition to type-II superconductivity is associated with the bunching of magnetic field lines into discrete superconducting flux tubes which possess enormous tension. The coupling of the crust to the flux tubes implies the existence of huge tangential magnetic fields at the crust-core interface. We show that the transition to superconductivity triggers a highly non-linear response in the Hall drift of the crustal magnetic field, an effect which was neglected in previous numerical modelling. We argue that at the time of the phase transition giant Hall waves are launched from the crust-core interface toward the surface. Our models show that if the crust contains a multipolar magnetic field $\sim 10^{13}$ G, the amplitude of the Hall waves is $\sim 10^{15}$ G. The elastic deformation of the lattice is included in our models, which allows us to track the time-dependent shear stresses everywhere in the crust. The simulations indicate that the Hall waves may be strong enough to break the crust, and could cause star quakes which trigger rotation glitches and changes in the radio pulse profile. The Hall waves also couple to slow magnetospheric changes which cause anomalous braking indices. The emission of the giant Hall waves from the crust-core interface facilitates fast flux expulsion from the superconducting core, provided that the flux tubes in the core are themselves sufficiently mobile. For all of the flux tube mobility prescriptions implemented in this work, the core approaches the Meissner state with B=0 at late times.

The world's first ever ''adaptive stellar coronagraph'' facility will be the PLACID instrument, installed on Turkey's new national observatory 4-m DAG telescope. PLACID incorporates a customized spatial light modulator (SLM) acting as a dynamically addressed focal-plane phase mask (FPM) coronagraph in the H-Ks bands. This new approach to high-contrast imaging will be applied on-sky in late 2024/early 2025. We present a first estimate of the science discovery space for PLACID, in terms of known exoplanets and brown dwarfs, considering raw lab contrast, contrast ratios, limiting magnitudes, coronagraphic inner working angle etc. In the future, we will also look into predicted disk and binary or multiple stars systems imaging performance, with the latter being a possible niche science case for the instrument (adaptive FPM for multiple stars). This work will inform on the first light PLACID commissioning activities and early science on the DAG telescope and is deemed to evolve in function of future developments on the DAG AO instrumentation suite.

The programmable Liquid-crystal Active Coronagraphic Imager for the DAG Telescope (PLACID) instrument will be installed on the Turkish 4-m Telescope by the fall of 2024 and is expected to be on-sky by the end of the year. PLACID will be the first ''active stellar coronagraph instrument'', equipped with a customized spatial light modulator (SLM), which performs as a dynamically programmable focal-plane phase mask (FPM) from H- to Ks- band. A Python-based numerical simulator of SLM-based focal-plane phase coronagraph is developed to investigate the effects of discrete pixelated FPM patterns in place of classical phase masks. The simulator currently explores the impacts of two design choices, spatial sampling in the coronagraphic focal-plane (number of SLM pixels per $\lambda$/D) and phase resolution (SLM greylevel steps). The preliminary results of the monochromatic simulations show that in ideal conditions (no wavefront errors) it is sufficient to use FPMs with spatial sampling of 10 SLM pixel per $\lambda$/D and phase resolution of 8 bits. The tool is expected to enable detailed simulations of PLACID or similar SLM-based instruments, and to help with real-time operations (optimal choice of FPM for given observing conditions) and interpretation of real data. Additionally, the tool is designed to integrate and simulate advanced operation modes, in particular focal-plane phase diversity for coherent differential imaging (CDI) of exoplanets.

The Programmable Liquid-crystal Active Coronagraphic Imager for the DAG telescope (PLACID) instrument is a novel high-contrast direct imaging facility that was recently delivered to the Turkish 4-m DAG telescope, with first light anticipated by the end of 2024. In a nutshell, PLACID consists in a fore-optics coronagraphic intermediate stage platform, installed in-between the TROIA XAO system and the DIRAC HAWAII-1RG focal-plane array. The PLACID project, led by a consortium of Swiss Universities contracted by the Atatürk University Astrophysics Research and Application Center (ATASAM), has passed the Delivery Readiness Review (DRR) milestone in September 2023, and was delivered to ATASAM campus facilities in March 2024. The PLACID commissioning activities with the calibration light source at the summit, on the DAG telescope Nasmyth platform, are foreseen to take place this fall, with first light scheduled to take place before the end of the year. When on-sky, PLACID will be the world's first ''active coronagraph'' facility, fielding a customized spatial light modulator (SLM) acting as a dynamically programmable focal-plane phase mask (FPM) coronagraph from H- to Ks-band. This will provide a wealth of novel options to observers, among which software-only abilities to change or re-align the FPM pattern in function of conditions or science requirements, free of any actuator motion. Future features will include non-common path aberrations (NCPA) self-calibration, optimized coronagraphy for binary stars, as well as coherent differential imaging (CDI). We hereby present the delivered PLACID instrument, its current capabilities, and Factory Acceptance commissioning results with relevant performance metrics.

Primordial black holes (PBHs) with initial mass $\sim5\times10^{14}$ g are evaporating due to Hawking radiation, leading to bursts of very-high-energy gamma rays. In this work, we investigate the prospective sensitivity of the Large High Altitude Air Shower Observatory (LHAASO) to measure the local burst rate density of PBHs. Our findings reveal that LHAASO is capable of searching for the PBH bursts within a distance $\sim0.1$ pc from the sun and thereby measure the local burst rate density $\sim$ 1164 (or 699)$\,\mathrm{pc}^{-3}\,\mathrm{yr}^{-1}$ at $99\%$ confidence level during a 3 (or 5) year observing run. This stands for a sensitivity that is one order of magnitude stronger than the strongest observational constraint from the High Altitude Water Cherenkov Observatory (HAWC). In addition, we further suggest an observing strategy to search for the PBH bursts during upcoming observing runs of LHAASO.

It has been generally accepted that the originators of the double star astronomy were Christian Mayer and William Herschel. We recovered the memory of the poorly known Italian astronomer Giovanni Battista Hodierna, who published the first catalogue of stellar binaries over a century before Mayer and Herschel. We analysed the fourth section of 1654 G. B. Hodierna's book "De systemate orbis cometici deque admirandis coeli characteribus". There, Hodierna listed a dozen pairs of stars whose identification with modern star names had been lost for centuries. To identify the pairs, we used Hodierna's Latin descriptions of location in constellations for all primary stars, ecliptic coordinates and angular separations to companions for some, and the Washington Double Star, Hipparcos, and Gaia catalogues. We were able to identify the twelve primaries and eleven multiple systems with companions, of which nine were double and two were triple. Besides, with up-to-date data, we confirmed that four systems are physically bound: Atlas and Pleione, alpha1,2 Lib, nu1,2 Dra, and theta1 Ori A, C, and D. The other seven pairs are alignments of very bright stars at different distances.

Tidal disruption events (TDE) occur when a star ventures too close to a massive black hole. In a partial TDE (pTDE), the star only grazes the tidal radius, causing the outer envelope of the star to be stripped away while the stellar core survives. Previous research has shown that a star, once tidally stripped in a parabolic orbit, can acquire enough orbital energy for its remnant to become a high-velocity star potentially capable of escaping the galaxy. Conversely, some studies have reported that the remnant may lose orbital energy and undergo re-disruption, leading to a recurring pTDE. This study aims to uncover the physical mechanisms and determine the conditions that lead to these divergent outcomes. We find that the orbital energy change only depends on the impact factor and the stellar structure, and barely depends on the mass of the black hole or the exact mass or orbital eccentricity of the star. For a $\gamma=5/3$ (or $\gamma=4/3$) polytropic star, after a pTDE its remnant gains orbital energy when the impact factor $\beta \gtrsim 0.62$ (or $\gtrsim 1.1$) or loses energy vice versa. Additionally, we verify an analytical equation for orbital energy change that is applicable across various systems. Through hydrodynamic simulations, we also explore the structure of the stellar remnant post-tidal stripping. Our findings provide critical insights for interpreting observed pTDEs and advancing knowledge on the orbital evolution and event rate of these events.

Fast, collimated jets are ubiquitous features of young stellar objects (YSOs). They are generally thought to be powered by disk accretion, but the details are debated. Through 2D (axisymmetric) MHD simulations, we find that a fast ($>100$~km/s) collimated bipolar jet is continuously driven along the north and south poles of the circumstellar disk that is initially magnetized by a large-scale open poloidal field and contains a thermally ionized inner magnetically active zone surrounded by a dead zone. The fast jet is primarily driven magneto-centrifugally by the release of the gravitational binding energy of the so-called ``avalanche accretion streams" near the boundary of an evacuated poloidal field-dominated polar region and a thick disk atmosphere raised by a toroidal magnetic field. Specifically, the fast outflow is driven along the upper (open) branch of the highly pinched poloidal field lines threading the (strongly magnetically braked) accretion streams where the density is relatively low so that the lightly loaded material can be accelerated magneto-centrifugally along the open field line to a high speed. The highly pinched poloidal magnetic fields threading the avalanche accretion streams tend to reconnect, enabling mass to accrete to the center without dragging along the poloidal magnetic flux with it. The reconnection provides a potential heating source for producing chondrules and calcium- and aluminum-rich inclusions (CAIs).

We present the first global Bayesian analysis of the time-ordered DIRBE data within the Cosmoglobe framework, building on the same methodology that has previously been successfully applied to Planck LFI and WMAP. These data are analyzed jointly with COBE-FIRAS, Gaia, Planck HFI, and WISE, allowing for more accurate instrumental and astrophysical characterization than possible through single-experiment analysis. This paper provides an overview of the analysis pipeline and main results, and we present and characterize a new set of zodiacal light subtracted mission average (ZSMA) DIRBE maps spanning 1.25 to 240 $\mu$m. A novel aspect of this processing is the characterization and removal of excess radiation between 4.9 and 60$\,\mu$m that appears static in solar-centric coordinates. The DR2 ZSMA maps have several advantages with respect to the previously available maps, including 1) lower zodiacal light (and possibly straylight) residuals; 2) better determined zero-levels; 3) natively HEALPix tessellated maps with a $7'$ pixel size; 4) nearly white noise at pixel scales; and 5) a more complete and accurate noise characterization established through the combination of MCMC samples and half-mission maps. In addition, because the model has been simultaneously fitted with both DIRBE and HFI data, this is the first consistent unification of the infrared and CMB wavelength ranges into one global sky model covering 100 GHz to 1 $\mu$m. However, even though the new maps are improved with respect to the official maps, and should be preferred for most future analyses that require DIRBE sky maps, they still exhibit non-negligible zodiacal light residuals between 12 and 60$\,\mu$m. Further improvements should be made through joint analysis with complementary infrared experiments such IRAS, AKARI, WISE and SPHEREx, and releasing the full combined potential of all these powerful infrared observatories.

Remote sensing observations by Hayabusa2 and laboratory measurements have revealed that the phyllosilicates on asteroid (162173) Ryugu are dehydrated/dehydroxylated due to space weathering. Reactive molecular dynamics simulations were performed to evaluate the magnitude of the dehydroxylation of Mg-rich serpentine by micrometeoroid impacts. When micrometeoroids were not coupled with interplanetary magnetic fields, serpentine could be dehydroxylated by micrometeoroids as small as 2 nm in size. In particular, ~200 O-H bonds dissociated when the meteoroids were derived from cometary activity (the impact velocity was ~20 km s$^{-1}$). When nano-sized dust particles were accelerated to ~300 km s$^{-1}$ by the magnetic fields of solar wind plasma, the number of dissociated O-H bonds increased by one order of magnitude. Consequently even 1 nm-sized dust particles can contribute to the space weathering of Ryugu. In all cases, Si-OH, H2O, and free OH were generated from the hydroxyls initially connected to Mg, which could partially offset dehydration. Despite the limitations of our computational resources, which restricted the simulation time scale to 1 ps, reactive molecular dynamic simulations demonstrated that micrometeoroid bombardment could influence the space weathering of asteroids.

We report the identification of two galaxy overdensities at $z\sim5.7$ in the sightline of the galaxy cluster Abell 2744. These overdensities consist of 25 and 17 member galaxies, spectroscopically confirmed with JWST NIRSpec/MSA and NIRCam/WFSS. Each overdensity has a total stellar mass of $\sim2\times10^{10} M_\odot$ and a star formation rate of $\sim200 M_\odot$/yr within a central region of radius $R=2$ Mpc (physical). The sensitive PRISM spectra allow us to identify six galaxies that show weak Ha+[NII] emissions within the overdensities ($27\pm6\%$), whereas the fraction of such galaxies is found significantly lower ($6\pm2\%$) in field samples of the equivalent redshift range. These weak emission line galaxies, dubbed as wELGs, exhibit a strong continuum break at $4000$AA rest-frame, a characteristic feature of evolved stellar populations. The high observed fraction of wELGs in the two overdensities is consistent with the idea that high-density environments are an ideal site where galaxies can accelerate their evolutionary pace compared to field analogs. Our study pinpoints an early onset of environmental effects, already important within one billion years after the Big Bang, and provides a complementary perspective on the emergence of quenched, massive galaxies at lower redshifts. Potential contributions from black hole accretion feedback to the reduction of star formation activity are discussed, but the connection to the local environments remains unclear.

The double detonation model is one of the prevalent explosion mechanisms of Type Ia Supernovae (SNe Ia) wherein an outer helium shell detonation triggers a core detonation in the white dwarf (WD). The dynamically driven double degenerate double detonation (D6) is the double detonation of the more massive WD in a binary WD system where the localized impact of the mass transfer stream from the companion sets off the initial helium shell detonation. To have high numerical resolution and control over the stream parameters, we have implemented a study of the local interaction of the stream with the WD surface in 2D. In cases with lower base density of the shell, the stream's impact can cause surface detonation soon after first impact. With higher base densities, after the stream hits the surface, hot material flows around the star and interacts with the incoming stream to produce a denser and narrower impact. Our results therefore show that (1) a directly impacting stream for both a relatively high resolution and for a range of stream parameters can produce a surface detonation, (2) thinner helium shells ignite more promptly via impact, doing so sooner, and (3) there are lower limits on ignition in both shell density and incoming stream speed with lower limits on density being well below those shown by other work to be required for normal appearing SN Ia. This supports stream ignition and therefore the D6 scenario, as a viable mechanism for normal SNe Ia.

We search for gamma-ray emission from the galaxy cluster SPT-CL J2012-5649 in the energy range from 3 GeV to 1 TeV using the DArk Matter Particle Explorer (DAMPE) telescope. For our analysis, we use three different templates: point source, radial disk and radial Gaussian. We do not detect a signal with significance $>3\sigma$ for any of these templates at any location with $R_{200}$ of the cluster center. We obtain 95\% c.l. upper limit on the energy flux between $\sim 10^{-6}$ and $10^{-4} \rm{MeV~cm^{-2}~s^{-1}}$ depending on the energy range. These upper limits are consistent with the a non-zero flux detected by Fermi-LAT (at $6\sigma$ significance) for this cluster. This work represents the first proof of principle search for gamma-ray emission from a single galaxy cluster using DAMPE data.

We report observations of the highly active FRB 20240114A with MeerKAT using the Ultra-High Frequency (UHF; $544\text{--}1088$ MHz) and L-band ($856\text{--}1712$ MHz) receivers. A total of 62 bursts were detected in coherent tied-array beams using the MeerTRAP real-time transient detection pipeline. We measure a structure-optimising dispersion measure of $527.65\pm0.01\,\text{pc}\,\text{cm}^{-3}$ using the brightest burst in the sample. We find the bursts of FRB 20240114A are generally detected in part of the broad band of MeerKAT, $\sim40\%$ in the UHF and $\sim30\%$ in the L-band, indicating the band limited nature. We analyse the fluence distribution of the 44 bursts detected at UHF, constraining the fluence completeness limit to $\sim1\,$Jy ms, above which the cumulative burst rate follows a power law $R (>F)\propto (F/1\,\text{Jy}\,\text{ms})^\gamma$ with $\gamma=-1.8\pm0.2$. Using channelised telescope data captured in our transient buffer we localise FRB 20240114A in the image domain to RA = 21h27m39.86s, Dec = +04d19m45.01s with an uncertainty of 1.4 arcsec. This localisation allows us to confidently identify the host galaxy of FRB 20240114A. Also using the transient buffer data we perform a polarimetric study and demonstrate that most of the bursts have $\sim100\%$ linear polarisation fractions and up to $\sim20\%$ circular polarisation fractions. Finally, we predict the flux density of a potential persistent radio source (PRS) associated with FRB 20240114A is $\backsimeq[0.6\text{--}60]\,\mu\text{Jy}$ based on the simple relation between the luminosity of the PRS and the rotation measure arising from the FRB local environment.

Measurement of lithium abundances in solar-type stars have shown that standard models of stellar evolution are incapable of explaining the observed depletion as a function of stellar age. Beryllium is one of the lightest elements that can be measured in stellar photospheres, and it can be burned in relatively low temperatures. Studying its abundances as a function of stellar age can provide important constraints to stellar mixing models, as the level of depletion as a function of time will indicate how deep the photospheric material must be dredged to explain the observed abundances of both elements. In an effort to provide the most stringent constraints for non-standard stellar mixing models, we observed a sample of solar-twins and concomitantly analyzed their lithium and beryllium abundances. Unlike what is typically observed for lithium, we find that beryllium does not decrease as a function of stellar age, constraining models that predict burning of both materials. Based on our data, models that invoke convective overshoot and convective settling are preferred over typical rotationaly-induced mixing models, as the later burn Be in excess while the former do not. Previous works also proposed mixing due to gravity waves as a possible explanation for observed abundances, which can fit our data as well. We also confirm previous finds of an increase in Be abundance as a function of metallicity, indicative of galactic production via cosmic ray spallation.

We present an improved zodiacal light model for COBE-DIRBE derived through global Bayesian analysis within the Cosmoglobe Data Release 2 framework. The parametric form of the ZL model is identical to that introduced by Kelsall et al. (1998), but the specific best-fit parameter values are re-derived using the combination of DIRBE Calibrated Individual Observations, Planck HFI sky maps, and WISE and Gaia compact object catalogs. Furthermore, the ZL parameters are fitted jointly with astrophysical parameters, such as thermal dust and starlight emission, and the new model takes into account excess radiation that appears stationary in solar-centric coordinates as reported in a companion paper. The relative differences between the predicted signals from K98 and our new model are $\lesssim 5\%$ in the 12 and 25 $\mu$m channels over the full sky. The zero-levels of the cleaned DR2 maps are lower than those of the K98 Zodiacal light Subtracted Mission Average maps by $\sim 10$ kJy/sr at 1.25-3.5 $\mu$m, which is larger than the entire predicted contribution from high-redshift galaxies to the Cosmic Infrared Background at the same wavelengths. The total RMS of each DR2 map at wavelengths up to and including 25 $\mu$m are $\sim 30$ $\%$ lower at high Galactic latitudes than the corresponding DIRBE ZSMA maps. Still, obvious ZL residuals can be seen in several of the DR2 maps, and further work is required to mitigate these. Joint analysis with existing and future high-resolution full-sky surveys such as AKARI, IRAS, Planck HFI, and SPHEREx will be essential both to break key degeneracies in the current model and to determine whether the reported solar-centric excess radiation has a ZL or instrumental origin. Thus, while the results presented in this paper do redefine the state-of-the-art for DIRBE modelling, it also only represents the first among many steps toward a future optimal Bayesian ZL model.

Analyzing images of the Cygnus Loop, a core-collapse supernova (CCSN) remnant, in different emission bands, we identify a point-symmetrical morphology composed of three symmetry axes that we attribute to shaping by three pairs of jets. The main jet axis has an elongated S shape, appearing as a faint narrow zone in visible and UV. We term it the S-shaped hose, and the structure of three symmetry lines, the point-symmetric wind rose. The two other lines connect a protrusion (an ear or a bulge) with a hole on the opposite side of the center (a nozzle or a cavity), structures that we identify in the X-ray, UV, visible, IR, and/or radio images. There is a well-known blowout at the southern end of the S-shaped hose, and we identify a possible opposite blowout at the northern end of the S-shaped hose. The point-symmetrical morphology of the Cygnus Loop is according to the expectation of the jittering jets explosion mechanism (JJEM) of CCSNe, where several to few tens of pairs of jets with stochastically varying directions explode the star. The three pairs of jets that shaped the wind-rose structure of the Cygnus Loop are the last energetic pairs of this series of jets. Our study further supports the JJEM as the main explosion mechanism of CCSNe.

We present an up-to-date compilation of published Hubble constant ($H_0$) measurements that are independent of the CMB sound horizon scale. This compilation is categorized into two distinct groups: A. Distance Ladder Measurements: This group comprises 19 recent measurements, primarily from the past four years, utilizing various rung 2 calibrators and rung 3 cosmic distance indicators. B.One-Step Measurements: This category includes 31 measurements of $H_0$ that are independent of both the CMB sound horizon scale and the distance ladder approach. These are derived from diverse probes such as Cosmic Chronometers, gamma-ray attenuation, time-delay strong lensing, megamasers etc. Statistical analysis reveals a significant distinction between these two groups. The distance ladder-based measurements yield a weighted mean $H_0 = 72.76 \pm 0.50$ km s$^{-1}$ Mpc$^{-1}$, while the one-step measurements result in a weighted mean $H_0 = 69.01 \pm 0.49$ km s$^{-1}$ Mpc$^{-1}$. To quantify the statistical significance of this difference, we implemented a Kolmogorov-Smirnov (KS) test, which yielded a p-value of 0.000102. This extremely low p-value strongly indicates that the two samples are fundamentally distinct, with a probability of less than 0.01\% that they are drawn from the same underlying distribution. These findings suggest that late-time one-step measurements of $H_0$ are more consistent with early-time measurements, indicating that the core of the Hubble tension lies not between early-time and late-time measurements per se, but specifically between distance ladder measurements and all other $H_0$ determinations. This discrepancy points to either a systematic effect influencing all distance ladder measurements or a fundamental physics anomaly affecting at least one rung of the distance ladder.

FU Ori objects are the most extreme eruptive young stars known. Their 4 to 5 magnitude photometric outbursts last for decades and are attributed to a factor of up to 10,000 increase in the stellar accretion rate. The nature of the accretion disk-to-star interface in FU Ori objects has remained a mystery for decades. To date, attempts to directly observe a shock or boundary layer have been thwarted by the apparent lack of emission in excess of the accretion disk photosphere down to $\lambda = 2300$ Å. We present a new NUV and the first high-sensitivity FUV spectrum of FU Ori. The FUV continuum is detected for the first time and, at $\lambda = 1400$ Å, is more than $10^4$ times brighter than predicted by a viscous accretion disk. We interpret the excess as arising from a shock at the boundary between the disk and the stellar surface. We model the shock emission as a blackbody and find that the temperature of the shocked material is $T_\mathrm{FUV} \approx 16,000 \pm 2000$ K. The shock temperature corresponds to an accretion flow along the surface of the disk that reaches a velocity of 40 km s$^{-1}$ at the boundary, consistent with predictions from simulations.

We use the First Light And Reionisation Epoch Simulations (FLARES) to study the evolution of the rest-frame ultraviolet (UV) and far-infrared (FIR) sizes for a statistical sample of massive ($\gtrsim10^{9}$M$_{\odot}$) high redshift galaxies (z $\in$ [5,10]). Galaxies are post-processed using the SKIRT radiative transfer code, to self-consistently obtain the full spectral energy distribution and surface brightness distribution. We create mock observations of the galaxies for the Near Infrared Camera (NIRCam) to study the rest-frame UV 1500 $\unicode{xC5}$ morphology. We also generate mock rest-frame FIR (50 $\mu$m) photometry and mock ALMA (158 $\mu$m) (0.01"-0.03" and $\approx$0.3" angular resolution) observations to study the dust-continuum. We find the effect of dust on observed sizes reduces with increasing wavelength from the UV to optical ($\sim$0.6 times the UV at 0.4$\mu$m), with no evolution in FIR sizes. Observed sizes vary within 0.4-1.2 times the intrinsic sizes at different signal to noise ratios (SNR = 5-20) across redshifts. The effect of PSF and noise makes bright structures prominent, whereas fainter regions blend with noise, leading to an underestimation (factor of 0.4-0.8) of sizes at SNR=5. At SNR=15-20, the underestimation reduces (factor of 0.6-0.9) at z=5-8 but due to PSF, at z=9-10, bright cores are dominant, resulting in an overestimation (factor of 1.0-1.2). For ALMA, low resolution sizes are effected by noise which acts as extended emission. The size evolution in UV broadly agrees with current observational samples and other simulations. This work is one of the first to analyse the panchromatic sizes of a statistically significant sample of simulated high-redshift galaxies, complementing a growing body of research highlighting the importance of conducting an equivalent comparison between observed galaxies and their simulated counterparts in the early Universe.

We explore correlations between the orientations of small galaxy groups, or "multiplets", and the large-scale gravitational tidal field. Using data from the Dark Energy Spectroscopic Instrument (DESI) Y1 survey, we detect the intrinsic alignment (IA) of multiplets to the galaxy-traced matter field out to separations of 100 Mpc/h. Unlike traditional IA measurements of individual galaxies, this estimator is not limited by imaging of galaxy shapes and allows for direct IA detection beyond redshift z = 1. Multiplet alignment is a form of higher-order clustering, for which the scale-dependence traces the underlying tidal field and amplitude is a result of small-scale (< 1 Mpc/h) dynamics. Within samples of bright galaxies (BGS), luminous red galaxies (LRG) and emission-line galaxies (ELG), we find similar scale-dependence regardless of intrinsic luminosity or colour. This is promising for measuring tidal alignment in galaxy samples that typically display no intrinsic alignment. DESI's LRG mock galaxy catalogues created from the AbacusSummit N-body simulations produce a similar alignment signal, though with a 33% lower amplitude at all scales. An analytic model using a non-linear power spectrum (NLA) only matches the signal down to 20 Mpc/h. Our detection demonstrates that galaxy clustering in the non-linear regime of structure formation preserves an interpretable memory of the large-scale tidal field. Multiplet alignment complements traditional two-point measurements by retaining directional information imprinted by tidal forces, and contains additional line-of-sight information compared to weak lensing. This is a more effective estimator than the alignment of individual galaxies in dense, blue, or faint galaxy samples.