Sazuna/UAT_keywords huggingface dataset:
From Halos to Galaxies. X. Decoding Galaxy SEDs with Physical Priors and Accurate Star Formation History Reconstruction. The spectral energy distribution (SED) of galaxies is essential for deriving fundamental properties like stellar mass and star formation history (SFH). However, conventional methods, including both parametric and nonparametric approaches, often fail to accurately recover the observed cosmic star formation rate (SFR) density due to oversimplified or unrealistic assumptions about SFH and their inability to account for the complex SFH variations across different galaxy populations. To address this issue, we introduce a novel approach that improves galaxy broadband SED analysis by incorporating physical priors derived from hydrodynamical simulations. Tests using IllustrisTNG simulations demonstrate that our method can reliably determine galaxy physical properties from broadband photometry, including stellar mass within 0.05 dex, current SFR within 0.3 dex, and fractional stellar formation time within 0.2 dex, with a negligible fraction of catastrophic failures. When applied to the Sloan Digital Sky Survey (SDSS) main photometric galaxy sample with spectroscopic redshift, our estimates of stellar mass and SFR are consistent with the widely used MPA-JHU and GSWLC catalogs. Notably, using the derived SFHs of individual SDSS galaxies, we estimate the cosmic SFR density and stellar mass density with remarkable consistency to direct observations up to z ~ 6. This demonstrates a significant advancement in deriving SFHs from SEDs that closely align with observational data. Consequently, our method can reliably recover observed spectral indices such as Dn(4000) and HδA by synthesizing the full spectra of galaxies using the estimated SFHs and metal enrichment histories, relying solely on broadband photometry as input. Furthermore, this method is extremely computationally efficient compared to conventional approaches.

Keywords: Galaxy properties, Galaxy colors, Galaxy quenching, Galaxy stellar content, Galaxy ages, Star formation, Galaxy evolution, Galaxy masses
Alignment Parameters: Quantifying Dense Core Alignment in Star-forming Regions. Recent high-resolution observations at millimeter (mm) and submillimeter wavelengths reveal a diverse spatial distribution for subparsec-scale dense cores within star-forming regions, ranging from clustered to aligned arrangements. To address the increasing volume of observational and simulation data, we introduce "alignment parameters" as a quantitative and reproducible method to automatically assess core alignment. We first demonstrate the effectiveness of these parameters by applying them to artificial test clumps and comparing the results with labels from visual inspection. A threshold value is then proposed to differentiate between "clustered" and "aligned" categories. Subsequently, we apply these parameters to dense cores identified from a sample of Atacama Large Millimeter/submillimeter Array 1.3 mm dust continuum images in high-mass star-forming regions. Analysis exploring correlations between alignment parameters and clump properties rules out the presence of a moderate or strong correlation, indicating that clump properties do not appear to strongly influence the outcome of fragmentation. One possible explanation for this is that the fragmentation process is chaotic, meaning that small variations in initial conditions can lead to significant differences in fragmentation outcomes, thus obscuring any direct link between clump properties and core alignment/distribution.

Keywords: Star forming regions, Star formation, Interstellar medium
JWST Discovery of a Very Fast Biconical Outflow of Warm Molecular Gas in the Nearby Ultraluminous Infrared Galaxy F08572+3915 NW. We present new James Webb Space Telescope (JWST) Mid-Infrared Instrument Medium-Resolution Spectrometer observations of the nearby ultraluminous infrared galaxy (ULIRG) F08572+3915 NW. These integral field spectroscopic (IFS) data reveal a kpc-scale warm-molecular rotating disk and biconical outflow traced by the H2ν = 0–0 S(1), S(2), S(3), and S(5) rotational transitions. The outflow maintains a relatively constant median (maximum) projected velocity of 1100 km s‑1 (3000 km s‑1) out to ∼1.4 kpc from the nucleus. The outflowing H2 material is slightly warmer (640–700 K) than the rotating disk material (460–520 K), perhaps due to shock heating in the highly turbulent outflowing material. This outflow shares the same kinematics and orientation as the sub-kiloparsec scale warm H2 outflow traced by the rovibrational H2 lines in Keck AO near-infrared IFS data. However, this warm H2 outflow is significantly faster than the sub-kiloparsec-scale cold molecular outflow derived from multi-transition far-infrared OH observations with Herschel and the greater than or equivalent to kiloparsec-scale cold molecular outflow mapped by millimeter-wave interferometric CO 1–0 observations with IRAM-PdBI and NOEMA. The new JWST data bolster the scenario where the buried quasar in this ULIRG is excavating the dust screen, accelerating perhaps as much as 60% of the dusty warm molecular material to velocities beyond the escape velocity, and thus influencing the evolution of the host galaxy.

Keywords: Infrared spectroscopy, Active galaxies, Galactic and extragalactic astronomy, Infrared astronomy, Galaxy winds, Infrared galaxies, Extragalactic astronomy, Ultraluminous infrared galaxies, Galaxies
Search for and Analysis of Eclipsing Binaries in the LAMOST Medium-resolution Survey Field. I. R.A.: 23<SUP>h</SUP>01<SUP>m</SUP>51<SUP>s</SUP>, Decl.: +34°36'45″. Eclipsing binaries (EBs) play an important astrophysical role in studying stellar properties and evolution. By analyzing photometric data in the the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Medium-Resolution Survey field, R.A.: 23h01m51 00, decl.: +34 , 48 EBs are detected and two are newly discovered. This specific field has been observed 52 times by the LAMOST Medium-Resolution Survey DR 9, which facilitates a comprehensive analysis of the EBs. For EBs with LAMOST medium-resolution spectra, radial velocity curves were obtained, and their precise orbital parameters were determined by simultaneously analyzing photometric light curves and radial velocity curves. For the other EBs with only photometric light curves, we used the q-search or the temperature ratio method to determine their initial mass ratios and then determined the orbital parameters. It is found that 15 EBs belong to detached systems, one to semi-detached systems, and 32 to contact systems. Based on the O ‑ C analysis for 26 EBs with sufficient eclipsing times, we found a long-term decrease in the orbital period of 11 EBs and a continuous increase of five EBs, which are due to the material transfer between the two components. The O ‑ C curve of 1 EB shows a distinct periodic variation, which is caused by the light travel time effect, and the third body is likely to be a black hole. By applying the spectral subtraction method to 13 EBs with LAMOST medium-resolution spectra, 10 systems exhibit distinct Hα emission lines, in which one system exhibits double-peaked lines near phases 0.25 and 0.75, implying strong chromospheric activity. In the massluminosities and mass–radius distributions, most of the more massive components are less evolved than the less massive ones.

Keywords: Close binary stars, Fundamental parameters of stars, Stellar activity, Eclipsing binary stars, Stellar evolution
An Enigmatic PeVatron in an Area around H II Region G35.6−0.5. Identifying Galactic PeVatrons (PeV particle accelerators) from ultrahigh-energy (UHE, &gt;100 TeV) γ-ray sources plays a crucial role in revealing the origin of Galactic cosmic rays. The UHE source 1LHAASO J1857+0203u is suggested to be associated with HESS J1858+020, which may be attributed to the possible PeVatron candidate supernova remnant (SNR) G35.6−0.4 or H II region G35.6−0.5. We perform detailed analysis on the very-high-energy and UHE γ-ray emissions toward this region with data from the Large High Altitude Air Shower Observatory (LHAASO). 1LHAASO J1857+0203u is detected with a significance of 11.6σ above 100 TeV, indicating the presence of a PeVatron. It has an extent of ∼0 18 with a power-law (PL) spectral index of ∼2.5 at 1─25 TeV and pointlike emission with a PL spectral index of ∼3.2 above 25 TeV. Using archival CO and H I data, we identify some molecular and atomic clouds that may be associated with the TeV γ-ray emissions. Our modeling indicates that the TeV γ-ray emissions are unlikely to arise from clouds illuminated by the protons that escaped from SNR G35.6−0.4. In the scenario in which H II region G35.6−0.5 could accelerate particles to the UHE band, the observed GeV─TeV γ-ray emission could be well explained by a hadronic model with a PL spectral index of ∼2.0 and cutoff energy of ∼450 TeV. However, an origin in an evolved pulsar wind nebula cannot be ruled out.

Keywords: Gamma-ray sources, Supernova remnants, H II regions, Gamma-rays
Unveiling the Dark Side of Ultraviolet/Optical Bright Galaxies: Optically Thick Dust Absorption. Over the past decades, a population of galaxies invisible in optical/near-infrared (NIR), but bright at longer wavelengths, have been identified through color selections. These so-called optically faint/dark galaxies are considered to be massive quiescent galaxies or highly dust-attenuated galaxies. Having the entire galaxy obscured by dust, however, is likely an extreme case of the much more common occurrence of optically thin and thick absorption coexisting in the same system. With the power of JWST imaging, we are able to spatially resolve massive galaxies at z ∼ 3, accurately model their spectral energy distributions, and identify candidate optically thick substructures. We target galaxies with  10.3 and 2.5 &lt; z &lt; 3.5, and get 486 galaxies in Cosmic Evolution Early Release Science Survey and Public Release Imaging for Extragalactic Research fields. Based on excess NIR luminosity, we identify 162 galaxies (∼33% of the parent sample) as candidate hosts of optically thick substructures. We then carry out spatially resolved spectral energy distribution modeling to explore the physical properties of those dark substructures and estimate the amount of optically thick obscuration. We find that optically thick dust is ubiquitous in normal massive galaxies with a wide variety of star formation rate (SFR) and morphology. 10%–20% of the stellar mass/SFR are unaccounted for in our selected galaxies, and the fraction is insensitive to stellar mass or SFR. The dark substructures are generally dustier than the rest of the galaxies and are irregularly distributed, arguing against an obscured active galactic nucleus as the source of the NIR excess. A correlation between the obscured luminosity and the presence of a recent starburst in the past ≲100 Myr is also observed.

Keywords: Interstellar dust extinction, James Webb Space Telescope, Star formation, Spectral energy distribution, High-redshift galaxies
Spectrum and Location of Ongoing Extreme Particle Acceleration in Cassiopeia A. Young supernova remnants (SNRs) are believed to be the origin of energetic cosmic rays (CRs) below the "knee" of their spectrum at ∼3 PeV (1015 eV). Nevertheless, the precise location, duration, and operation of CR acceleration in young SNRs are open questions. Here, we report on multiepoch X-ray observations of Cassiopeia A (Cas A), a 350 yr old SNR, in the 15–50 keV band that probes the most energetic CR electrons. The observed X-ray flux decrease (15% ± 1% over 10 yr), contrary to the expected &gt;90% decrease based on previous radio, X-ray, and gamma-ray observations, provides unambiguous evidence for CR electron acceleration operating in Cas A. A temporal model for the radio and X-ray data accounting for electron cooling and continuous injection finds that the freshly injected electron spectrum is significantly harder (exponential cutoff power-law index q = 2.15), and its cutoff energy is much higher (Ecut = 36 TeV), than the relic electron spectrum (q = 2.44 ± 0.03, Ecut = 4 ± 1 TeV). Both electron spectra are naturally explained by the recently developed modified nonlinear diffusive shock acceleration (mNLDSA) mechanism. The CR protons producing the observed gamma rays are likely accelerated at the same location by the same mechanism as the injected electrons. The Cas A observations and spectral modeling represent the first time radio, X-ray, gamma-ray, and CR spectra have been self-consistently tied to a specific acceleration mechanism—mNLDSA—in a young SNR.

Keywords: Supernova remnants, X-ray astronomy, Galactic cosmic rays
A Subclass of Gamma-Ray Burst Originating from Compact Binary Merger. Type I gamma-ray bursts (GRBs) are believed to originate from compact binary mergers usually with a duration of main emission less than 2 s. However, recent observations of GRB 211211A and GRB 230307A indicate that some merger-origin GRBs could last much longer. Since they show strikingly similar properties (indicating a common mechanism), which are different from the classic "long"-short burst (e.g., GRB 060614), we find they form an interesting subclass of type I GRBs, and we suggest to name them as type IL GRB. We find that the prompt emission of type IL GRB is composed of three episodes: (1) a precursor followed by a short quiescent (or weak emission) period, (2) a long-duration main emission, and (3) an extended emission. With this burst pattern, a good candidate, GRB 170228A, was found in the Fermi/Gamma-ray Burst Monitor archive data. Temporal and spectral analyses indeed show that GRB 170228A falls in the same group with GRB 211211A and GRB 230307A in many diagnostic figures. Thus, this burst pattern could be a good reference for rapidly identifying type IL GRBs and very helpful for conducting low-latency follow-up observation. We estimated the occurrence rate and discussed the physical origins and implications for the three emission episodes of type IL GRBs. Our analysis suggests the premerger precursor model, especially the magnetar super flare model, is more favored for type IL GRBs. More observations in multiwavelength and multimessenger are required to deepen our understanding of this subclass of GRB.

Keywords: Gamma-ray bursts
Early Enrichment Population Theory at High Redshift. An early enrichment population (EEP) has been theorized to produce the observed intracluster medium (ICM) metallicity of galaxy clusters. This population likely existed at high redshifts (z ∼ 10), relics of which we posit exist today as dwarf galaxies. Previous work has argued that the initial mass function (IMF) of the EEP must be flatter than those found at lower redshifts, but with considerable uncertainties. In this work, we present a more quantitative model for the EEP and demonstrate how observational constraints can be applied to the IMF using supernova Type Ia (SN Ia) rates, delay time distributions (DTDs), and the luminosity functions (LFs) of galaxy clusters. We determine best-fit values for the slope and mass break of the IMF by comparing IMFs from literature with observed DTDs and the low-luminosity component (M(R) &gt; −12) of the Coma LF. We derive two best-fit IMFs, flatter than standard IMFs: (1) αlo = −0.13 ± 0.24 for 0.07 &lt; M/M⊙ &lt; 1.75 and αhi = 0.53 ± 0.01 for 1.75 &lt; M/M⊙ &lt; 150; and (2) αlo = 1.06 ± 0.11 for 0.07 &lt; M/M⊙ &lt; 6 and αhi = 0.53 ± 0.01 for 6 &lt; M/M⊙ &lt; 150. We compare these with sl-5 from M. Loewenstein (2013), with α = 0.5 for 0.07 &lt; M/M⊙ &lt; 8 and α = 0.3 for 8 &lt; M/M⊙ &lt; 150. This EEP model, along with stars formed at later times, can produce the observed ICM metallicity, is consistent with observations, and predicts a significant rise in the SN Ia rate at increasing redshift.

Keywords: Galaxy clusters, Luminosity function, Initial mass function, Intracluster medium, Metallicity, Supernovae
The Multiple Extended Tidal Tails of NGC 288. Using photometry and proper motions from Pan-STARRS, DECaLS, and Gaia Data Release 3, we detect a ∼35°–70° long trailing stellar debris stream associated with the globular cluster NGC 288. The trajectory of the trailing tail is not well matched by a model stream evolved in a static Galactic potential, but is reasonably well matched by a stream modeled in a potential that incorporates a massive, infalling Large Magellanic Cloud. We also detect a broad, at least ∼40° long leading tail that appears to be composed of at least two narrower, spatially offset, and kinematically distinct streams. Stream modeling predicts a similar broad composite of streams and suggests that these narrower components could each be made up of one or more generations of tidal tails, each formed during different orbits over the past few gigayears. On the other hand, NGC 288 is believed to have been brought into the Galactic halo during the Gaia–Enceladus–Sausage accretion event, and the tangential velocity dispersions of our stream candidates are indeed mostly consistent with having been stripped in a parent galaxy that had a large, cored dark matter halo. Tables of the most highly ranked stream star candidates are provided for ongoing and future spectroscopic surveys.

Keywords: Globular star clusters, Milky Way dark matter halo, Tidal tails, Stellar streams
A Magnetohydrodynamics Simulation of Coronal Mass Ejections in the Upper Corona at 2.5R<SUB>⊙</SUB> ≤ r ≤ 19R<SUB>⊙</SUB>. The methodology of a new magnetohydrodynamics simulation model of the propagation of coronal mass ejections (CMEs) in the near-Sun solar wind region at 2.5R⊙ ≥ r ≥ 19R⊙ is presented. The simulation model first determines the steady state of the transonic/Alfvénic solar wind with the characteristic-based inner boundary treatment for the middle of the corona at r = 2.5R⊙ (K. Hayashi et al. 2023). To determine the numerical perturbation on the 2.5 R⊙inner boundary surface, a kinetic self-similar model with a torus-shaped magnetic-field rope and a spherically symmetric plasma structure translating and expanding at the constant speed (named TICK model) is developed. A solar-wind MHD model (C.-C. Wu et al. 2020b) traces the temporal evolution of the injected CME through the inner boundary surface. We conducted test simulations with various choices of plasma density and temperature. The test simulation results show that the injected CME, particularly its internal magnetic structure, can be substantially altered through the interactions with the preexisting slow and dense ambient solar wind at the early phase of the propagation in the near-Sun region. The propagation speed of the discontinuity front is found to be dependent on the plasma parameters of the CME perturbation. Therefore, for better simulating the propagation of the CME, it is important for the CME models to include the nonlinear MHD interactions in the subsonic/Alfvénic regions.

Keywords: Solar wind, Solar coronal mass ejections, Magnetohydrodynamical simulations
Foreshock Ultralow Frequency Waves at Mars: Consequence on the Particle Acceleration Mechanisms at the Martian Bow Shock. Using Mars Atmosphere and Volatile EvolutioN Magnetometer observations, we report the first statistical study of ultralow frequency (ULF) waves at the Martian foreshock. The analyzed foreshock ULF wave events are observed in the 0.008–0.086 Hz frequency range, with nearly circular and elliptical left-handed polarization in the spacecraft reference frame. These waves are propagated quasi-parallel to the ambient magnetic field, with a moderate wave amplitude. All these properties are consistent with fast magnetosonic waves, most likely generated through the ion–ion right-hand resonant instability. In addition, our results suggest that the associated resonant backstreaming protons' velocities parallel to the mean magnetic field in the solar wind reference frame are 1.33 ± 0.40 times the solar wind velocity. The similarity between our results and previous reports at other foreshocks may indicate the presence of a common acceleration process acting in planetary bow shocks and that is responsible for this particular backstreaming population.

Keywords: Planetary magnetospheres, Plasma physics
An Effect Study of Structural Jets on the Long Gamma-Ray Burst Formation Rate at Low Redshift. Gamma-ray bursts (GRBs) are considered the most violent explosions in the Universe. Numerous studies have analyzed the formation rate of long gamma-ray bursts (LGRBs), which originate from the core collapse of massive stars, in comparison with the star formation rate (SFR). It is found that the LGRB formation rate at redshift z &lt; 1 is significantly distinct from the SFR and is higher. Moreover, due to the threshold of detectors, the structured jets of GRBs also affect detection numbers at different redshifts, which all influence the calculation of the formation rate. Thus we investigate the LGRB formation rate at low redshift and further explore the possible correlation between the LGRB formation rate under the influence of structural jets and the SFR. We use Lynden-Bell's c‑ method to study the luminosity function and rate of Swift LGRBs without any assumptions. After correcting for the redshift evolution, the luminosity function can be expressed as   for dim LGRBs and   for bright LGRBs, and the formation rate at z &lt; 1 shows an increase. Then we use Monte Carlo simulations to create pseudo-GRBs with structured jets and calculate the formation rates assuming that the actual LGRB formation rate at low redshift is proportional to the SRF. The results demonstrate that structural jets increase the number of detections at low redshift in response to observational effects. Compared with the observed formation rate, the structured jet model with Gauss-cocoon is found to be relatively more efficient, and the parameters η of this model are limited and analyzed to [0.5, 5].

Keywords: Burst astrophysics, Gamma-ray bursts, Star formation
Most Super-Earths Have Less Than 3% Water. Super-Earths are highly irradiated, small planets with bulk densities approximately consistent with Earth. We construct combined interior atmosphere models of super-Earths that trace the partitioning of water throughout a planet, including an iron-rich core, silicate-rich mantle, and steam atmosphere. We compare these models with exoplanet observations to infer a 1σ upper limit on the total water mass fraction of ≲3% at the population level. We consider end-member scenarios that may change this value, including the efficiency of mantle outgassing, escape of high mean molecular weight atmospheres, and increased iron core mass fractions. Although our constraints are agnostic as to the origin of water, we show that our upper limits are consistent with its production via chemical reactions of primordial hydrogen-dominated atmospheres with magma oceans. This mechanism has also been hypothesised to explain Earth's water content, possibly pointing to a unified channel for the origins of water on small terrestrial planets.

Keywords: Exoplanet structure, Exoplanet evolution, Exoplanet formation, Exoplanets