Sazuna/UAT_keywords huggingface dataset:
Why Do Semianalytic Models Predict Higher Scatter in the Stellar Mass–Halo Mass Relation Than Cosmological Hydrodynamic Simulations?. Semianalytic models (SAMs) systematically predict higher-stellar mass scatter at a given halo mass than hydrodynamical simulations and most empirical models. Our goal is to investigate the physical origin of this scatter by exploring modifications to the physics in the SAM DARK SAGE. We design two black hole formation models that approximate results from the ILLUSTRISTNG 300-1 hydrodynamical simulation. In the first model, we assign a fixed black hole mass of 106 M ⊙ to every halo that reaches 1010.5 M ⊙. In the second model, we disregard any black hole growth as implemented in the standard DARK SAGE model. Instead, we force all black hole masses to follow the median z = 0 black hole mass–halo mass relation in ILLUSTRISTNG 300-1 with an imposed fixed scatter. We find that each model on its own does not significantly reduce the scatter in stellar mass. To explore the effects of active galactic nucleus (AGN) feedback in addition to black hole seeding, we replace the native Dark Sage AGN feedback model with a simple model where we turn off cooling for galaxies with black hole masses above 108 M ⊙. With the additional modification in AGN feedback, we find that the supermassive black hole seeding and fixed conditional distribution models create a significant reduction in the scatter in stellar mass at halo masses between 1011–14 M ⊙. These results suggest that AGN feedback in SAMs acts in a qualitatively different way than feedback implemented in cosmological simulations. Either or both may require substantial modification to match the empirically inferred scatter in the stellar mass–halo mass relation.

Keywords: Hydrodynamical simulations, Galaxy formation, Galaxy evolution, Astronomical simulations
The Cosmic Ultraviolet Baryon Survey (CUBS). IX. The Enriched Circumgalactic and Intergalactic Medium Around Star-forming Field Dwarf Galaxies Traced by O VI Absorption. The shallow potential wells of star-forming dwarf galaxies make their surrounding circumgalactic and intergalactic medium (CGM/IGM) sensitive laboratories for studying the inflows and outflows thought to regulate galaxy evolution. We present new absorption-line measurements in quasar sight lines, probing within projected distances of &lt;300 kpc from 91 star-forming field dwarf galaxies with a median stellar mass of  logM⋆/M⊙≍8.3  at 0.077 &lt; z &lt; 0.73, from the Cosmic Ultraviolet Baryon Survey (CUBS). In this redshift range, the CUBS quasar spectra cover a suite of transitions including H I, low, and intermediate metal ions (e.g., C II, Si II, C III, and Si III), and highly ionized O VI. This CUBS-Dwarfs survey enables constraints with samples nine times larger than past dwarf CGM/IGM studies with similar ionic coverage. We find that low and intermediate ionization metal absorption is rare around dwarf galaxies, consistent with previous surveys of local dwarfs. In contrast, highly ionized O VI is commonly observed in sight lines that pass within the virial radius of a dwarf, and O VI detection rates are nonnegligible at projected distances of 1−2× the virial radius. Based on these measurements, we estimate that the O VI-bearing phase of the CGM/IGM accounts for a dominant share of the metal budget of dwarf galaxies. The absorption kinematics suggest that a relatively modest fraction of the O VI-bearing gas is formally unbound. Together, these results imply that low-mass systems at z ≲ 1 effectively retain a substantial fraction of their metals within the nearby CGM and IGM.

Keywords: Dwarf galaxies, Circumgalactic medium, Intergalactic medium
Equilibrium States of Galactic Atmospheres. I. The Flip Side of Mass Loading. This paper presents a new framework for understanding the relationship between a galaxy and its circumgalactic medium (CGM). It focuses on how imbalances between heating and cooling cause either expansion or contraction of the CGM. It does this by tracking all of the mass and energy associated with a halo's baryons, including their gravitational potential energy, even if feedback has pushed some of those baryons beyond the halo's virial radius. We show how a star-forming galaxy's equilibrium state can be algebraically derived within the context of this framework, and we analyze how the equilibrium star formation rate depends on supernova feedback. We consider the consequences of varying the mass loading parameter  ηM≡Ṁwind/Ṁ*  relating a galaxy's gas mass outflow rate ( Ṁwind ) to its star formation rate ( Ṁ* ) and obtain results that challenge common assumptions. In particular, we find that equilibrium star formation rates in low-mass galaxies are generally insensitive to mass loading, and when mass loading does matter, increasing it actually results in more star formation because more supernova energy is needed to resist atmospheric contraction.

Keywords: Galaxy evolution, Galactic winds, Stellar feedback, Circumgalactic medium
Equilibrium States of Galactic Atmospheres. II. Interpretation and Implications. The scaling of galaxy properties with halo mass suggests that feedback loops regulate star formation, but there is no consensus yet about how those feedback loops work. To help clarify discussions of galaxy-scale feedback, Paper I presented a very simple model for supernova feedback that it called the minimalist regulator model. This follow-up paper interprets that model and discusses its implications. The model itself is an accounting system that tracks all of the mass and energy associated with a halo's circumgalactic baryons—the central galaxy's atmosphere. Algebraic solutions for the equilibrium states of that model reveal that star formation in low-mass halos self-regulates primarily by expanding the atmospheres of those halos, ultimately resulting in stellar masses that are insensitive to the mass-loading properties of galactic winds. What matters most is the proportion of supernova energy that couples with circumgalactic gas. However, supernova feedback alone fails to expand galactic atmospheres in higher-mass halos. According to the minimalist regulator model, an atmospheric contraction crisis ensues, which may be what triggers strong black hole feedback. The model also predicts that circumgalactic medium properties emerging from cosmological simulations should depend largely on the specific energy of the outflows they produce, and we interpret the qualitative properties of several numerical simulations in light of that prediction.

Keywords: Galactic winds, Galaxy evolution, Stellar feedback, Circumgalactic medium
Sigmoid Eruption Associated with the X9.3 Flare from AR 12673 Drives the Gradual Solar Energetic Particle Event on 2017 September 6. Large gradual solar energetic particle (SEP) events can pose a radiation risk to crewed spaceflight and a significant threat to near-Earth satellites; however, the origin of the SEP seed particle population, and how these particles are released, accelerated and transported into the heliosphere are not well understood. We analyze NOAA active region (AR) 12673, which was the source responsible for multiple large gradual SEP events during 2017 September, and found that almost immediately after each significant eruptive event associated with SEPs an enhanced Si/S abundance ratio was measured by Wind, consistent with the previous work by Brooks et al. The EUV Imaging Spectrometer (EIS) onboard Hinode took data roughly 8 hr before the second SEP event on 2017 September 6, which allowed the regions of enhanced Si/S abundance ratio in the AR to be determined. We have shown that the AR contains plasma with elemental abundance values detected in situ by Wind. In particular, the plasma originates from the core of the AR, similar to Brooks et al., but in the moss (footpoints) associated with hot sigmoidal AR loops. The sigmoid, which contains highly fractionated plasma, erupts and propagates toward an Earth-connected magnetic null point, providing a direct channel for the highly fractionated plasma to escape and be detected in the near-Earth environment.

Keywords: Solar flares, Solar magnetic reconnection, Solar energetic particles, Solar abundances, Solar coronal mass ejections, Solar magnetic fields
Multispectral Sirens: Gravitational-wave Cosmology with (Multi-) Subpopulations of Binary Black Holes. The cosmic expansion rate can be directly measured with gravitational-wave (GW) data of the compact binary mergers by jointly constraining the mass function of the population and the cosmological model via the so-called spectral sirens. Such a method relies on the features in the mass functions, which may originate from some individual subpopulations and hence become blurred/indistinct due to the superposition of different subpopulations. In this work, we propose a novel approach to constrain the cosmic expansion rate with subpopulations of GW events, named multispectral sirens. The advantage of the multispectral sirens compared to the traditional spectral sirens is demonstrated by the simulation with the mock data. The application of this approach to the GWTC-3 data yields  H0=73.3‑25.6+29.9Mpc‑1kms‑1  (median and symmetric 68.3% credible interval), which is about 19% tighter than the result inferred with the traditional spectral sirens utilizing a POWERLAW+PEAK mass function. The incorporation of the bright standard siren GW170817 with a uniform prior in [10, 200] (log-uniform prior in [20,140]) Mpc‑1 km s‑1 gives  H0=71.1‑7.5+15.0(70.3‑7.1+12.9)Mpc‑1kms‑1  (68.3% confidence level), corresponding to an improvement of ∼26% (23%) with respect to the measurement from sole GW170817.

Keywords: Hubble constant, Stellar mass black holes, Astrophysical black holes
Test of Cosmic Web-feeding Model for Star Formation in Galaxy Clusters in the COSMOS Field. It is yet to be understood how large-scale environments influence star formation activity in galaxy clusters. One recently proposed mechanism is that galaxy clusters can remain star forming when fed by infalling groups and star-forming galaxies from large-scale structures (LSSs) surrounding them (the "web-feeding" model). Using the COSMOS2020 catalog that has half a million galaxies with high-accuracy (σ ∆z/1+z  ∼ 0.01) photometric redshifts, we study the relationship between star formation activities in galaxy clusters and their surrounding environment to test the web-feeding model. We first identify 68 cluster candidates at 0.3 ≤ z ≤ 1.4 with halo masses at 1013.0─1014.5 M ⊙ and the surrounding LSSs with the friends-of-friends algorithm. We find that clusters with low fractions of quiescent galaxies tend to be connected with extended LSSs as expected in the web-feeding model. We also investigated the time evolution of the web-feeding trend using the IllustrisTNG cosmological simulation. Even though no clear correlation between the quiescent galaxy fraction of galaxy clusters and the significance of LSSs around them is found in the simulation, we verify that the quiescent galaxy fractions of infallers such as groups (M 200 ≥ 1012 M ⊙) and galaxies (M 200 &lt; 1012 M ⊙) are smaller than the quiescent fraction of cluster members and that infallers can lower the quiescent fraction of clusters. These results imply that cluster-to-cluster variations of quiescent galaxy fraction at z ≤ 1 can at least partially be explained by feeding materials through cosmic webs to clusters.

Keywords: Extragalactic astronomy, Galaxy clusters, Large-scale structure of the universe
Could the Interband Lag of Active Galactic Nucleus Vary Randomly?. The interband lags among the optical broad-band continua of active galactic nuclei (AGNs) have been intensively explored over the past decade. However, the nature of the lags remains under debate. Here, utilizing two distinct scenarios for AGN variability, i.e., the thermal fluctuation of accretion disk and the reprocessing of both the accretion disk and clouds in the broad line region, we show that, owing to the random nature of AGN variability, the interband lags of an individual AGN would vary from one campaign with a finite baseline to another. Specifically, the thermal fluctuation scenario implies larger variations in the lags than the reprocessing scenario. Moreover, the former predicts a positive correlation between the lag and variation amplitude, while the latter does not result in such a correlation. For both scenarios, averaging the lags of an individual AGN measured with repeated and nonoverlapping campaigns would give rise to a stable lag, which is larger for a longer baseline and gets to saturation for a sufficiently long baseline. However, obtaining the stable lag for an individual AGN is very time-consuming. Alternatively, it can be equivalently inferred by averaging the lags of a sample of AGNs with similar physical properties, and thus can be properly compared with predictions of AGN models. In addition, several new observational tests suggested by our simulations are discussed, as well as the role of the deep high-cadence surveys of the Wide Field Survey Telescope in enriching our knowledge of the lags.

Keywords: Active galactic nuclei, Time domain astronomy
Constraints on Remnant Planetary Systems as a Function of Main-sequence Mass with HST/COS. As the descendants of stars with masses less than 8 M ⊙ on the main sequence, white dwarfs provide a unique way to constrain planetary occurrence around intermediate-mass stars (spectral types BAF) that are otherwise difficult to measure with radial-velocity or transit surveys. We update the analysis of more than 250 ultraviolet spectra of hot (13,000 K &lt; T eff &lt; 30,000 K), young (less than 800 Myr) white dwarfs collected by the Hubble Space Telescope, which reveals that more than 40% of all white dwarfs show photospheric silicon and sometimes carbon, signposts for the presence of remnant planetary systems. However, the fraction of white dwarfs with metals significantly decreases for massive white dwarfs (M WD &gt; 0.8 M ⊙), descendants of stars with masses greater than 3.5 M ⊙ on the main sequence, as just  11‑4+6 % exhibit metal pollution. In contrast, 44% ± 6% of a subset of white dwarfs (M WD &lt; 0.7 M ⊙) unbiased by the effects of radiative levitation are actively accreting planetary debris. While the population of massive white dwarfs is expected to be influenced by the outcome of binary evolution, we do not find merger remnants to broadly affect our sample. We connect our measured occurrence rates of metal pollution on massive white dwarfs to empirical constraints of planetary formation and survival around stars with masses greater than 3.5 M ⊙ on the main sequence.

Keywords: Ultraviolet astronomy, Stellar kinematics, White dwarf stars, Exoplanets
Streaming Instabilities in Accreting Protoplanetary Disks: A Parameter Study. The streaming instability (SI) is currently the leading candidate for triggering planetesimal formation in protoplanetary disks. Recently, a novel variation, the "azimuthal-drift" streaming instability (AdSI), was discovered in disks exhibiting laminar gas accretion. Unlike the classical SI, the AdSI does not require pressure gradients and can concentrate dust even at low abundances. We extend previous simulations of the AdSI to explore the impact of dust abundance, accretion-flow strength, pressure gradients, and grain size. For a dimensionless accretion-flow strength α M = 0.1 and particle Stokes number St = 0.1, we find the AdSI produces dust filaments for initial dust-to-gas ratios as low as ϵ = 0.01. For ϵ ≳ 1, maximum dust-to-gas ratios of order 100 are attained, which can be expected to undergo gravitational collapse. Furthermore, even in systems dominated by the classical SI, an accretion flow drives filament formation, without which the disk remains in a state of small-scale turbulence. Our results suggest that an underlying accretion flow facilitates dust concentration and may thus promote planetesimal formation.

Keywords: Hydrodynamical simulations, Magnetohydrodynamics, Protoplanetary disks, Astrophysical fluid dynamics, Planet formation
Evolutionary States and Triplicity of Four Massive Semidetached Binaries with Long-term Decreasing Orbital Periods in the LMC. The massive semidetached binary with a long-term decreasing orbital period may involve a rapid mass-transfer phase in Case A, and thus, they are good astrophysical laboratories for investigating the evolution of massive binary stars. In this work, by using the long-term observational light curves from the Optical Gravitational Lensing Experiment project and other data in the low-metallicity Large Magellanic Cloud, four semidetached massive binaries with long-term decreases in the orbital periods are detected from 165 EB-type close binaries. It is found that the more massive component in S07798 is filling its Roche lobe, where the period decrease is caused by mass transfer from the primary to the secondary. However, the other three (S03065, S12631, S16873) are semidetached binaries with a lobe-filling secondary where the mass transfer between the components should cause the period to increase if the angular momentum is conservative. The long-term period decreases in these three systems may be caused by angular momentum loss. Additionally, the orbital periods of three systems (S03065, S07798, S16873) are detected to show cyclic variation with periods shorter than 11 yr, which can be plausibly explained by the presence of close-in third bodies in these massive binaries. Based on all of these results, it is suggested that the detected four semidetached binaries almost have multiplicity. The companion stars are crucial for the origin and evolution of these massive close binaries.

Keywords: Eclipsing binary stars, Early-type stars, Multiple stars, Early stellar evolution
WALLABY Pilot Survey: Gas-rich Galaxy Scaling Relations from Marginally Resolved Kinematic Models. We present the first set of galaxy scaling relations derived from kinematic models of the Widefield Australian Square Kilometer Array Pathfinder (ASKAP) L-band Legacy All-sky Blind surveY (WALLABY) pilot phase observations. Combining the results of the first and second pilot data releases, there are 236 available kinematic models. We develop a framework for robustly measuring H I disk structural properties from these kinematic models, applicable to the full WALLABY survey. Utilizing this framework, we obtained the H I size, a measure of the rotational velocity, and angular momentum for 148 galaxies. These comprise the largest sample of galaxy properties from an untargeted, uniformly observed, and modeled H I survey to date. We study the neutral atomic hydrogen (H I) size–mass, size–velocity, mass–velocity, and angular momentum–mass scaling relations. We calculate the slope, intercept, and scatter for these scaling relations and find that they are similar to those obtained from other H I surveys. We also obtain stellar masses for 92 of the 148 robustly measured galaxies using multiband photometry through Dark Energy Sky Instrument Legacy Imaging Survey Data Release 10 images. We use a subset of 61 of these galaxies that have consistent optical and kinematic inclinations to examine the stellar and baryonic Tully–Fisher relations as well as the gas fraction–disk stability and gas fraction–baryonic mass relations. These measurements and relations demonstrate the unprecedented resource that WALLABY will represent for resolved galaxy scaling relations in H I.

Keywords: Galaxy kinematics, Galaxies, Scaling relations
Searching for Emission Lines at z &gt; 11: The Role of Damped Lyα and Hints About the Escape of Ionizing Photons. We describe new ultradeep James Webb Space Telescope (JWST) NIRSpec PRISM and grating spectra for the galaxies JADES-GS-z11-0 ( zspec=11.122‑0.003+0.005 ) and JADES-GS-z13-0 ( zspec=13.20‑0.04+0.03 ), the most distant spectroscopically confirmed galaxy discovered in the first year of JWST observations. The extraordinary depth of these observations (75 hr and 56 hr, respectively) provides a unique opportunity to explore the redshifts, stellar properties, UV magnitudes, and slopes for these two sources. For JADES-GS-z11-0, we find evidence for multiple emission lines, including [O II]λ λ3726, 3729 and [Ne III]λ3869, resulting in a spectroscopic redshift we determine with 94% confidence. We present stringent upper limits on the emission-line fluxes and line equivalent widths for JADES-GS-z13-0. At this spectroscopic redshift, the Lyα break in JADES-GS-z11-0 can be fit with a damped Lyα absorber with  log(NHI/cm‑2)=22.42‑0.120+0.093 . These results demonstrate how neutral hydrogen fraction and Lyman-damping wings may impact the recovery of spectroscopic redshifts for sources like these, providing insight into the overprediction of the photometric redshifts seen for distant galaxies observed with JWST. In addition, we analyze updated NIRCam photometry to calculate the morphological properties of these resolved sources, and find a secondary source 0.″3 south of JADES-GS-z11-0 at a similar photometric redshift, hinting at how galaxies grow through interactions in the early Universe.

Keywords: Galaxy abundances, High-redshift galaxies, Galaxy evolution
Exploration of Halo Substructures in Integrals-of-motion Space with Gaia Data Release 3. Using kinematic data from the Gaia Data Release 3 catalog, along with metallicity estimates robustly derived from Gaia BP/RP spectra, we have explored the Galactic stellar halo in search of both known and potentially new substructures. By applying the Hierarchical Density-Based Spatial Clustering of Applications with Noise clustering algorithm in integrals-of-motion space (i.e., E, L  z , and L ⊥  =Lx2+Ly2 ), we identified five previously known substructures: Gaia-Sausage-Enceladus (GSE), Helmi streams, I'itoi and Sequoia, and the hot thick disk. We additionally found NGC 3201 and NGC 5139 in this work, and NGC 3201 shares similar distributions in phase space and metallicities to Arjuna, which possibly implies that they have the same origin. Three newly discovered substructures are Prograde Substructure 1 (PG1), Prograde Substructure 2 (PG2), and the Low Energy Group. PG1, with a higher V  ϕ  than typical GSE member stars, is considered as either a low-eccentricity and metal-rich part of GSE or part of the metal-poor disk. PG2, sharing kinematic similarities with Aleph, is thought to be its relatively highly eccentric component or the mixture of Aleph and the disk. The Low Energy Group, whose metal-poor component of metallicity distribution function has a mean value [M/H] ∼ ‑1.29 (compared to that of Heracles [M/H] ∼ ‑1.26), may have associations with Heracles.

Keywords: Galaxy stellar halos, Galaxy dynamics, Galaxy kinematics
Proposed Importance of HOCO Chemistry: Inefficient Formation of CO<SUB>2</SUB> from CO and OH Reactions on Ice Dust. With the advent of JWST ice observations, dedicated studies on the formation reactions of detected molecules are becoming increasingly important. One of the most interesting molecules in interstellar ice is CO2. Despite its simplicity, the main formation reaction considered, CO + OH → CO2 + H through the energetic HOCO* intermediate on ice dust, is subject to uncertainty because it directly competes with the stabilization of HOCO as a final product, which is formed through energy dissipation of HOCO* to the water ice. When energy dissipation to the surface is effective during the reaction, HOCO can be a dominant product. In this study, we experimentally demonstrate that the major product of the reaction is indeed not CO2, but rather the highly reactive radical HOCO. The HOCO radical can later evolve into CO2 through H-abstraction reactions, but these reactions compete with additional reactions, leading to the formation of carboxylic acids (R-COOH). Our results highlight the importance of HOCO chemistry and encourage further exploration of the chemistry of this radical.

Keywords: Molecular data, Laboratory astrophysics, Astrochemistry, Dense interstellar clouds, Interstellar medium, Interstellar dust processes