Sazuna/UAT_keywords huggingface dataset:
The Gas Accretion Rate of Galaxies over z ≈ 0-1.3. We present here estimates of the average rates of accretion of neutral gas onto main-sequence galaxies and the conversion of atomic gas to molecular gas in these galaxies at two key epochs in galaxy evolution: (i) z ≈ 1.3-1.0, toward the end of the epoch of peak star formation activity in the Universe, and (ii) z ≈ 1-0, when the star formation activity declines by an order of magnitude. We determine the net gas accretion rate R Acc and the molecular gas formation rate R Mol by combining the relations between the stellar mass and the atomic gas mass, the molecular gas mass, and the star formation rate (SFR) at three epochs, z = 1.3, z = 1.0, and z = 0, with the assumption that galaxies evolve continuously on the star-forming main sequence. We find that, for all galaxies, R Acc is far lower than the average SFR R SFR at z ≈ 1.3-1.0; however, R Mol is similar to R SFR during this interval. Conversely, both R Mol and R Acc are significantly lower than R SFR over the later interval, z ≈ 1-0. We find that massive main-sequence galaxies had already acquired most of their present-day baryonic mass by z ≈ 1.3. At z ≈ 1.3-1.0, the rapid conversion of the existing atomic gas to molecular gas was sufficient to maintain a high average SFR, despite the low net gas accretion rate. However, at later times, the combination of the lower net gas accretion rate and the lower molecular gas formation rate leads to a decline in the fuel available for star formation and results in the observed decrease in the SFR density of the Universe over the last 8 Gyr.

Keywords: Galaxies
XUE: Molecular Inventory in the Inner Region of an Extremely Irradiated Protoplanetary Disk. We present the first results of the eXtreme UV Environments (XUE) James Webb Space Telescope (JWST) program, which focuses on the characterization of planet-forming disks in massive star-forming regions. These regions are likely representative of the environment in which most planetary systems formed. Understanding the impact of environment on planet formation is critical in order to gain insights into the diversity of the observed exoplanet populations. XUE targets 15 disks in three areas of NGC 6357, which hosts numerous massive OB stars, including some of the most massive stars in our Galaxy. Thanks to JWST, we can, for the first time, study the effect of external irradiation on the inner (&lt;10 au), terrestrial-planet-forming regions of protoplanetary disks. In this study, we report on the detection of abundant water, CO, 12CO2, HCN, and C2H2 in the inner few au of XUE 1, a highly irradiated disk in NGC 6357. In addition, small, partially crystalline silicate dust is present at the disk surface. The derived column densities, the oxygen-dominated gas-phase chemistry, and the presence of silicate dust are surprisingly similar to those found in inner disks located in nearby, relatively isolated low-mass star-forming regions. Our findings imply that the inner regions of highly irradiated disks can retain similar physical and chemical conditions to disks in low-mass star-forming regions, thus broadening the range of environments with similar conditions for inner disk rocky planet formation to the most extreme star-forming regions in our Galaxy.

Keywords: Pre-main sequence stars, Protoplanetary disks, Planet formation
Formation of a Massive Lenticular Galaxy Under the Tidal Interaction with a Group of Dwarf Galaxies. Based on the atomic-hydrogen (H I) observations using the Five-hundred-meter Aperture Spherical radio Telescope, we present a detailed study of the gas-rich massive S0 galaxy NGC 1023 in a nearby galaxy group. The presence of a H I extended warped disk in NGC 1023 indicates that this S0 galaxy originated from a spiral galaxy. The data also suggest that NGC 1023 is interacting with four dwarf galaxies. In particular, one of the largest dwarf galaxies has fallen into the gas disk of NGC 1023, forming a rare bright-dark galaxy pair with a large gas clump. This clump shows the signature of a galaxy but has no optical counterpart, implying that it is a newly formed starless galaxy. Our results first suggest that a massive S0 galaxy in a galaxy group can form via the morphological transformation from a spiral under the joint action of multiple tidal interactions.

Keywords: Galaxy formation, Galaxy evolution
Electron Injection via Modified Diffusive Shock Acceleration in High-Mach-number Collisionless Shocks. The ability of collisionless shocks to efficiently accelerate nonthermal electrons via diffusive shock acceleration (DSA) is thought to require an injection mechanism capable of preaccelerating electrons to high enough energy where they can start crossing the shock front potential. We propose, and show via fully kinetic plasma simulations, that in high-Mach-number shocks electrons can be effectively injected by scattering in kinetic-scale magnetic turbulence produced near the shock transition by the ion Weibel, or current filamentation, instability. We describe this process as a modified DSA mechanism where initially thermal electrons experience the flow velocity gradient in the shock transition and are accelerated via a first-order Fermi process as they scatter back and forth. The electron energization rate, diffusion coefficient, and acceleration time obtained in the model are consistent with particle-in-cell simulations and with the results of recent laboratory experiments where nonthermal electron acceleration was observed. This injection model represents a natural extension of DSA and could account for electron injection in high-Mach-number astrophysical shocks, such as those associated with young supernova remnants and accretion shocks in galaxy clusters.

Keywords: Supernova remnants, Laboratory astrophysics, Cosmic ray sources
A Unified Picture of Short and Long Gamma-Ray Bursts from Compact Binary Mergers. The recent detections of the ~10 s long γ-ray bursts (GRBs) 211211A and 230307A followed by softer temporally extended emission (EE) and kilonovae point to a new GRB class. Using state-of-the-art first-principles simulations, we introduce a unifying theoretical framework that connects binary neutron star (BNS) and black hole-NS (BH-NS) merger populations with the fundamental physics governing compact binary GRBs (cbGRBs). For binaries with large total masses, M tot ≳ 2.8 M ⊙, the compact remnant created by the merger promptly collapses into a BH surrounded by an accretion disk. The duration of the pre-magnetically arrested disk (MAD) phase sets the duration of the roughly constant power cbGRB and could be influenced by the disk mass, M  d . We show that massive disks (M  d  ≳ 0.1 M ⊙), which form for large binary mass ratios q ≳ 1.2 in BNS or q ≲ 3 in BH-NS mergers, inevitably produce 211211A-like long cbGRBs. Once the disk becomes MAD, the jet power drops with the mass accretion rate as $\dot{M}\sim {t}^{-2}$ , establishing the EE decay. Two scenarios are plausible for short cbGRBs. They can be powered by BHs with less massive disks, which form for other q values. Alternatively, for binaries with M tot ≲ 2.8 M ⊙, mergers should go through a hypermassive NS (HMNS) phase, as inferred for GW170817. Magnetized outflows from such HMNSs, which typically live for ≲1 s, offer an alternative progenitor for short cbGRBs. The first scenario is challenged by the bimodal GRB duration distribution and the fact that the Galactic BNS population peaks at sufficiently low masses that most mergers should go through an HMNS phase.

Keywords: Neutron stars, Gamma-ray bursts, Jets, Black holes, Stellar mergers, Relativistic jets, Astrophysical black holes
Estimating Coronal Mass Ejection Mass and Kinetic Energy by Fusion of Multiple Deep-learning Models. Coronal mass ejections (CMEs) are massive solar eruptions, which have a significant impact on Earth. In this paper, we propose a new method, called DeepCME, to estimate two properties of CMEs, namely, CME mass and kinetic energy. Being able to estimate these properties helps better understand CME dynamics. Our study is based on the CME catalog maintained at the Coordinated Data Analysis Workshops Data Center, which contains all CMEs manually identified since 1996 using the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory. We use LASCO C2 data in the period between 1996 January and 2020 December to train, validate, and test DeepCME through 10-fold cross validation. The DeepCME method is a fusion of three deep-learning models, namely ResNet, InceptionNet, and InceptionResNet. Our fusion model extracts features from LASCO C2 images, effectively combining the learning capabilities of the three component models to jointly estimate the mass and kinetic energy of CMEs. Experimental results show that the fusion model yields a mean relative error (MRE) of 0.013 (0.009, respectively) compared to the MRE of 0.019 (0.017, respectively) of the best component model InceptionResNet (InceptionNet, respectively) in estimating the CME mass (kinetic energy, respectively). To our knowledge, this is the first time that deep learning has been used for CME mass and kinetic energy estimations.

Keywords: Solar atmosphere, Convolutional neural networks, Solar coronal mass ejections
Solar Energetic Particle Track-production Rates at 1 au: Comparing In Situ Particle Fluxes with Lunar Sample-derived Track Densities. Heavy (Z &gt; 26) solar energetic particles (SEPs) with energies ~1 MeV nucleon-1 are known to leave visible damage tracks in meteoritic materials. The density of such "solar flare tracks" in lunar and asteroidal samples has been used as a measure of a sample's exposure time to space, yielding critical information on planetary space weathering rates, the dynamics and lifetimes of interplanetary dust grains, and the long-term history of solar particle fluxes. Knowledge of the SEP track accumulation rate in planetary materials at 1 au is critical for properly interpreting observed track densities. Here, we use in situ particle observations of the 0.50-3.0 MeV nuc-1 Fe-group SEP flux taken by NASA's Advanced Composition Explorer (ACE) to calculate a flux of track-inducing particles at 1 au of 6.0 × 105 cm-2 yr-1 str-1. Using the observed energy spectrum of Fe-group SEPs, we find that the depth distribution of SEP-induced damage tracks inferred from ACE measurements matches closely to that recently measured in lunar sample 64455; however, the magnitude of the ACE-inferred rate is approximately 25× higher than that observed in the lunar sample. We discuss several hypotheses for the nature of this discrepancy, including inefficiencies in track formation, thermal annealing of lunar samples, erosion via space weathering processing, and variations in the SEP flux at the Moon, yet find no satisfactory explanation. We encourage further research on both the nature of SEP track formation in meteoritic materials and the flux of Fe-group SEPs at the lunar surface in recent and geologic times to resolve this discrepancy.

Keywords: Solar energetic particles, Interplanetary dust
An Extended Lyα Outflow from a Radio Galaxy at z = 3.7?. Spatially resolved observations of active galactic nuclei (AGN) host galaxies undergoing feedback processes are one of the most relevant avenues through which galactic evolution can be studied, given the long-lasting effects AGN feedback has on gas reservoirs, star formation, and AGN environments at all scales. Within this context, we report results from Very Large Telescope/MUSE integral field optical spectroscopy of TN J1049-1258, one of the most powerful radio sources known, at a redshift of 3.7. We detected extended (~18 kpc) Lyα emission, spatially aligned with the radio axis, redshifted by 2250 ± 60 km s-1 with respect to the host galaxy systemic velocity, and cospatial with UV continuum emission. This Lyα emission could arise from a companion galaxy, although there are arguments against this interpretation. Alternatively, it might correspond to an outflow of ionized gas stemming from the radio galaxy. The outflow would be the highest redshift spatially resolved ionized outflow to date. The enormous amount of energy injected, however, appears to be unable to quench the host galaxy's prodigious star formation, occurring at a rate of ~4500 M ☉yr-1, estimated using its far-infrared luminosity. Within the field, we also found two companion galaxies at projected distances of ~25 and ~60 kpc from the host, which suggests the host galaxy is harbored within a protocluster.

Keywords: Radio galaxies, Active galactic nuclei, Radio jets, High-redshift galaxy clusters
The Preexplosion Environments and the Progenitor of SN 2023ixf from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). Supernova (SN) 2023ixf was discovered on 2023 May 19. The host galaxy, M101, was observed by the Hobby-Eberly Telescope Dark Energy Experiment collaboration over the period 2020 April 30-2020 July 10, using the Visible Integral-field Replicable Unit Spectrograph (3470 ≲ λ ≲ 5540 Å) on the 10 m Hobby-Eberly Telescope. The fiber filling factor within ±30″ of SN 2023ixf is 80% with a spatial resolution of 1″. The r &lt; 5.″5 surroundings are 100% covered. This allows us to analyze the spatially resolved preexplosion local environments of SN 2023ixf with nebular emission lines. The two-dimensional maps of the extinction and the star formation rate (SFR) surface density (ΣSFR) show weak increasing trends in the radial distributions within the r &lt; 5.″5 regions, suggesting lower values of extinction and SFR in the vicinity of the progenitor of SN 2023ixf. The median extinction and that of the surface density of SFR within r &lt; 3″ are E(B - V) = 0.06 ± 0.14, and ${{\rm{\Sigma }}}_{\mathrm{SFR}}={10}^{-5.44\pm 0.66}\,{M}_{\odot }\,{\mathrm{yr}}^{-1}\,{\mathrm{arcsec}}^{-2}.$ There is no significant change in extinction before and after the explosion. The gas metallicity does not change significantly with the separation from SN 2023ixf. The metal-rich branch of the R 23 calculations indicates that the gas metallicity around SN 2023ixf is similar to the solar metallicity (~Z ☉). The archival deep images from the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) show a clear detection of the progenitor of SN 2023ixf in the z band at 22.778 ± 0.063 mag, but nondetections in the remaining four bands of CFHTLS (u, g, r, i). The results suggest a massive progenitor of ≈22 M ☉.

Keywords: Supernovae
Deciphering Solar Coronal Heating: Energizing Small-scale Loops through Surface Convection. The solar atmosphere is filled with clusters of hot small-scale loops commonly known as coronal bright points (CBPs). These ubiquitous structures stand out in the Sun by their strong X-ray and/or extreme-ultraviolet (EUV) emission for hours to days, which makes them a crucial piece when solving the solar coronal heating puzzle. In addition, they can be the source of coronal jets and small-scale filament eruptions. Here we present a novel 3D numerical model using the Bifrost code that explains the sustained CBP heating for several hours. We find that stochastic photospheric convective motions alone significantly stress the CBP magnetic field topology, leading to important Joule and viscous heating concentrated around the CBP's inner spine at a few megameters above the solar surface. We also detect continuous upflows with faint EUV signals resembling observational dark coronal jets and small-scale eruptions when Hα fibrils interact with the reconnection site. We validate our model by comparing simultaneous CBP observations from the Solar Dynamics Observatory (SDO) and the Swedish 1‑m Solar Telescope (SST) with observable diagnostics calculated from the numerical results for EUV wavelengths as well as for the Hα line using the Multi3D synthesis code. Additionally, we provide synthetic observables to be compared with Hinode, Solar Orbiter, and the Interface Region Imaging Spectrograph (IRIS). Our results constitute a step forward in the understanding of the many different facets of the solar coronal heating problem.

Keywords: Observational astronomy, Solar atmosphere, Magnetohydrodynamics, Computational methods, Solar corona, Solar chromosphere
A Self-interacting Dark Matter Solution to the Extreme Diversity of Low-mass Halo Properties. The properties of low-mass dark matter (DM) halos appear to be remarkably diverse relative to cold, collisionless DM predictions, even in the presence of baryons. We show that self-interacting DM (SIDM) can simultaneously explain observations of halo diversity at two opposite extremes-the inner density profile of the dense substructure perturbing the strong lens galaxy SDSSJ0946+1006 and the rotation curves of isolated, gas-rich ultradiffuse galaxies (UDGs). To achieve this, we present the first cosmological zoom-in simulation featuring strong DM self-interactions in a galaxy group environment centered on a 1013 M ⊙ host halo. In our SIDM simulation, most surviving subhalos of the group-mass host are deeply core-collapsed, yielding excellent candidates for the observed dense strong-lens perturber. Self-interactions simultaneously create kiloparsec-scale cores in low-concentration isolated halos, which could host the observed UDGs. Our scenario can be further tested with observations of DM structure and galaxies over a wide mass range.

Keywords: Galaxy dark matter halos, Strong gravitational lensing, N-body simulations, Dark matter, Low surface brightness galaxies
Accretion-modified Stars in Accretion Disks of Active Galactic Nuclei: The Low-luminosity Cases and an Application to Sgr A*. In this paper, we investigate the astrophysical processes of stellar-mass black holes (sMBHs) embedded in advection-dominated accretion flows (ADAFs) of supermassive black holes (SMBHs) in low-luminosity active galactic nuclei. The sMBH is undergoing Bondi accretion at a rate lower than the SMBH. Outflows from the sMBH-ADAF dynamically interact with their surroundings and form a cavity inside the SMBH-ADAF, thereby quenching the accretion onto the sMBH. Rejuvenation of the Bondi accretion is rapidly done by turbulence. These processes give rise to quasi-periodic episodes of sMBH activities and create flickerings from relativistic jets developed by the Blandford-Znajek mechanism if the sMBH is maximally rotating. Accumulating successive sMBH-outflows trigger a viscous instability of the SMBH-ADAF, leading to a flare following a series of flickerings. Recently, the similarity of near-infrared flare's orbits has been found by GRAVITY/VLTI astrometric observations of Sgr A∗: their loci during the last 4 yr consist of a ring in agreement with the well-determined SMBH mass. We apply the present model to Sgr A*, which shows quasi-periodic flickerings. An sMBH of ~40M ⊙ is preferred orbiting around the central SMBH of Sgr A* from fitting radio to X-ray continuum. Such an extreme mass ratio inspiraling provides an excellent laboratory for LISA/Taiji/Tianqin detection of mHz gravitational waves with strains of ~10-17, as well as their polarization.

Keywords: Active galaxies
Gas-phase Ortho-to-para Ratio of Formaldehyde Formed at Low Temperatures in Laboratory Ices. The ortho-to-para ratio (OPR) of formaldehyde (H2CO) has been used as a probe to estimate the formation temperature of molecules in interstellar, circumstellar, and cometary environments, relying on the assumption that nuclear spin conversion is extremely slow, preserving the OPR from molecular formation. An OPR for H2CO less than 3 corresponds to a spin temperature below 30 K and has been proposed to result from formation at low temperatures within an ice, whereas an OPR of 3 is interpreted as arising from warmer formation in the gas phase. In spite of this common assumption, there is no laboratory evidence in the literature to date in support of it. Here, in the first study of its kind for H2CO, we report rotational spectroscopy measurements of the OPR of H2CO sublimated after its formation in methanol (CH3OH) ice samples that were photolyzed by ultraviolet light at 10, 15, 20, and 40 K. None of the measured OPR values correlated with the ice formation temperature.

Keywords: Molecular physics, Laboratory astrophysics, Molecular spectroscopy, Astrochemistry
Formation of a Long Filament Through the Connection of Two Filament Segments Observed by CHASE. We present imaging and spectroscopic diagnostics of a long filament during its formation with the observations from the Chinese Hα Solar Explorer and Solar Dynamics Observatory. The seed filament first appeared at about 05:00 UT on 2022 September 13. Afterward, it grew gradually and connected to another filament segment nearby, building up a long filament at about 20:00 UT on the same day. The CHASE Hα spectra show an obvious centroid absorption with mild broadening at the main spine of the long filament, which is interpreted as evidence of filament material accumulation. More interestingly, near the footpoints of the filament, persistent redshifts have been detected in the Hα spectra during the filament formation, indicating continuous drainage of filament materials. Furthermore, through inspecting the extreme-ultraviolet (EUV) images and magnetograms, it was found that EUV jets and brightenings appeared repeatedly at the junction of the two filament segments, where opposite magnetic polarities converged and canceled each other continuously. These results suggest the occurrence of intermittent magnetic reconnection that not only connects magnetic structures of the two filament segments but also supplies cold materials for the filament channel likely by the condensation of injected hot plasma, even though a part of the cold materials falls down to the filament footpoints at the same time.

Keywords: Solar filaments, Solar magnetic reconnection
Rapid Premerger Localization of Binary Neutron Stars in Third-generation Gravitational-wave Detectors. Premerger localization of binary neutron stars (BNSs) is one of the most important scientific goals for the third-generation (3G) gravitational-wave detectors. It will enable the electromagnetic observation of the whole process of BNS coalescence, especially for the premerger and merger phases, which have not been observed yet, opening a window for deeper understandings of compact objects. To reach this goal, we describe a novel combination of multiband matched filtering and semianalytical localization algorithms to achieve early-warning localization of long BNS signals in 3G detectors. Using our method we are able to efficiently simulate one month of observations with a three-detector 3G network, and show that it is possible to provide accurate sky localizations more than 30 minutes before the merger. Our simulation shows that there could be ~10 (~100) BNS events localized within 100 deg2, 20 (6) minutes before merger, per month of observation.

Keywords: Gravitational wave astronomy, Compact binary stars, Gravitational waves
On the Lifetime of Molecular Clouds with the "Tuning-fork" Analysis. The "tuning-fork" (TF) analysis of CO and Hα emission has been used to estimate the lifetimes of molecular clouds in nearby galaxies. With simple model calculations, we show that this analysis does not necessarily estimate cloud lifetimes, but instead captures a duration of the cloud evolutionary cycle, from dormant to star-forming, and then back to a dormant phase. We adopt a hypothetical setup in which molecular clouds (e.g., traced in CO) live forever and form stars (e.g., H II regions) at some frequency, which then drift away from the clouds. The TF analysis still returns a timescale for the immortal clouds. This model requires drifting motion to separate the newborn stars from the clouds, and we discuss its origin. We also discuss the physical origin of the characteristic spatial separation term in the TF analysis and a bias due to systematic error in the determination of the reference timescale.

Keywords: Galaxy evolution, Star formation, Molecular clouds, Interstellar medium