Sazuna/UAT_keywords huggingface dataset:
Size─Stellar Mass Relation and Morphology of Quiescent Galaxies at z ≥ 3 in Public JWST Fields. We present the results of a systematic study of the rest-frame optical morphology of quiescent galaxies at z ≥ 3 using the Near-Infrared Camera (NIRCam) on board the James Webb Space Telescope (JWST). Based on a sample selected by UVJ color or NUVUVJ color, we focus on 26 quiescent galaxies with $9.8\lt \mathrm{log}({M}_{\star }/{M}_{\odot })\lt 11.4$ at 2.8 &lt; z phot &lt; 4.6 with publicly available JWST data. Their sizes are constrained by fitting the Sérsic profile to all available NIRCam images. We see a negative correlation between the observed wavelength and the size and derive their size at the rest frame 0.5 μm using size measurements in multiple bands. Our quiescent galaxies show a significant correlation between the rest-frame 0.5 μm size and the stellar mass at z ≥ 3. The analytical fit for them at $\mathrm{log}({M}_{\star }/{M}_{\odot })\gt 10.3$ implies that our size─stellar mass relations are below those at lower redshifts, with the amplitude of ∼0.6 kpc at M ⋆ = 5 × 1010 M ☉. This value agrees with the extrapolation of the size evolution of quiescent galaxies at z &lt; 3 in the literature, implying that the size of quiescent galaxies increases monotonically from z ∼ 3─5. Our sample mainly comprises galaxies with bulge-like structures according to their median Sérsic index and axis ratio of n ∼ 3─4 and q ∼ 0.6─0.8, respectively. On the other hand, there is a trend of increasing fraction of galaxies with low Sérsic index at higher redshift, suggesting 3 &lt; z &lt; 5 might be the epoch of onset of morphological transformation with a fraction of very notable disky quenched galaxies.

Keywords: Quenched galaxies, Galaxy evolution, Galaxy quenching, High-redshift galaxies, Galaxy radii
Probing the Diversity of Type Ia Supernova Light Curves in the Open Supernova Catalog. The ever-growing sample of observed supernovae (SNe) enhances our capacity for comprehensive SN population studies, providing a richer data set for understanding the diverse characteristics of Type Ia supernovae (SNe Ia) and possibly those of their progenitors. Here, we present a data-driven analysis of observed SN Ia photometric light curves collected in the Open Supernova Catalog. Where available, we add the environmental information from the host galaxy. We focus on identifying subclasses of SNe Ia without imposing the predefined subclasses found in the literature to date. To do so, we employ an implicit rank-minimizing autoencoder neural network for developing low-dimensional data representations, providing a compact representation of the SN light-curve diversity. When we analyze light curves alone, we find that one of our resulting latent variables is strongly correlated with redshift, allowing us to approximately "de-redshift" the other latent variables describing each event. After doing so, we find that three of our latent variables account for ∼95% of the variance in our sample, and provide a natural separation between 91T and 91bg thermonuclear SNe. Of note, the 02cx subclass is not unambiguously delineated from the 91bg sample in our results, nor do either the overluminous 91T or the underluminous 91bg/02cx samples form a clearly distinct population from the broader sample of "other" SN Ia events. We identify the physical characteristics of SN light curves that best distinguish SNe 91T from SNe 91bg and 02cx, and discuss prospects for future refinements and applications to other classes of SNe as well as other transients.

Keywords: Type Ia supernovae, Astronomy data analysis, Catalogs, Neural networks
Impact of Overlapping Signals on Parameterized Post-Newtonian Coefficients in Tests of Gravity. Gravitational waves have been instrumental in providing deep insights into the nature of gravity. Next-generation detectors, such as the Einstein Telescope, are predicted to have a higher detection rate given the increased sensitivity and lower cutoff frequency. However, this increased sensitivity raises challenges concerning parameter estimation due to the foreseeable overlap of signals from multiple sources. Overlapping signals (OSs), if not properly identified, may introduce biases in estimating post-Newtonian (PN) coefficients in parameterized tests of general relativity (GR). We investigate how OSs affect ‑1PN to 2PN terms in parameterized GR tests, examining their potential to falsely suggest GR deviations. We estimate the prevalence of such misleading signals in next-generation detectors, and their collective influence on GR tests. We compare the effects of OSs on coefficients at different PN orders, concluding that overall the 1PN coefficient suffers the most. Our findings also reveal that while a nonnegligible portion of OSs exhibit biases in PN coefficients that might individually prefer to conclude deviations from GR, collectively, the direction to deviate is random and a statistical combination will still be in favor of GR.

Keywords: General relativity, Gravitational waves, Compact binary stars
Contribution of γ-Ray Burst Afterglow Emissions to the Isotropic Diffuse γ-Ray Background. The isotropic diffuse γ-ray background (IGRB) serves as a fundamental probe of the evolution of the extreme Universe. Although various astrophysical sources have been proposed as potential contributors to the IGRB, the dominant population is still under debate. γ-ray bursts (GRBs) are among candidate contributors of IGRB, although they are not as frequently discussed as blazars or starburst galaxies. Recent observations of TeV emission from GRB afterglows have provided fresh insights into this subject. This work aims to investigate the potential contribution of GRB afterglows to the IGRB under the standard afterglow model. We carefully examine the influence of each microphysical parameter of the afterglow model on this contribution, with a particular emphasis on the significant role played by the initial kinematic energy. To determine the energy and quantify the contribution of GRB afterglow to IGRBs, we utilize the observed GRB afterglow energy emissions from the Swift X-ray Telescope and Fermi Large Area Telescope instruments. Our calculations, considering the synchrotron self-Compton emission, suggest that GRB afterglows make up less than 10% of the IGRBs. To enhance the precision of our findings, it is crucial to further constrain these parameters by conducting additional ground-based observations of GRB afterglows.

Keywords: Gamma-ray bursts
SN 2022joj: A Potential Double Detonation with a Thin Helium Shell. We present photometric and spectroscopic data for SN 2022joj, a nearby peculiar Type Ia supernova (SN Ia) with a fast decline rate (Δm 15,B = 1.4 mag). SN 2022joj shows exceedingly red colors, with a value of approximately B ‑ V ≈ 1.1 mag during its initial stages, beginning from 11 days before maximum brightness. As it evolves, the flux shifts toward the blue end of the spectrum, approaching B ‑ V ≈ 0 mag around maximum light. Furthermore, at maximum light and beyond, the photometry is consistent with that of typical SNe Ia. This unusual behavior extends to its spectral characteristics, which initially displayed a red spectrum and later evolved to exhibit greater consistency with typical SNe Ia. Spectroscopically, we find strong agreement between SN 2022joj and double detonation models with white dwarf masses of around 1 M ⊙ and a thin He shell between 0.01 and 0.05 M ⊙. Moreover, the early red colors are explained by line-blanketing absorption from iron peak elements created by the double detonation scenario in similar mass ranges. The nebular spectra in SN 2022joj deviate from expectations for double detonation, as we observe strong [Fe III] emission instead of [Ca II] lines as anticipated, though this is not as robust a prediction as early red colors and spectra. The fact that as He shells get thinner these SNe start to look more like normal SNe Ia raises the possibility that this is the triggering mechanism for the majority of SNe Ia, though evidence would be missed if the SNe are not observed early enough.

Keywords: Type Ia supernovae, Supernovae
Small-scale Anisotropies of Cosmic Rays from Turbulent Flow. Within the classical convection–diffusion approximation, we show that the angular distribution of cosmic rays (CRs) in a highly turbulent flow may exhibit significant small-scale anisotropies. The CR intensity angular power spectrum C  ℓ  is then a direct reflection of interstellar turbulence, from which one expects C  ℓ  ∝ ℓ ‑γ‑1 for ℓ ≫ 1, where γ is the power-law turbulence spectral index. Observations by IceCube and HAWC at TeV energies can be explained approximately with the Kolmogorov law γ = 5/3 with a convection velocity dispersion of 20 km s‑1 on the scale of 10 pc.

Keywords: Interstellar dynamics, High energy astrophysics, Cosmic ray astronomy, Interstellar plasma, Galactic cosmic rays, Interstellar medium, Particle astrophysics, Cosmic rays
Alpha-to-proton Temperature Ratio Distributions Using Parker Solar Probe Measurements. The distributions of the temperature excess of alphas to protons (ɛ) were studied using Parker Solar Probe measurements for Encounters 2 through 14. The distributions were mapped based on heliographic distance, Coulomb number, plasma β, and Alfvén Mach number (M  A ). The importance of collisional effects in the thermalization of solar wind is observed for a wide range of Coulomb numbers. The distributions correlate better with N β and NM  A  than just N. Furthermore, evidence was found for a narrow region immediately above the Alfvén surface (1 &lt; M  A  &lt; 2) where ɛ has values much higher than the mass ratio.

Keywords: Solar energetic particles, Space weather, Solar wind
The Optical to Infrared 0.6–5.3 μm Dust Extinction Law of the Milky Way with JWST NIRSpec: Westerlund 2. The interstellar extinction law is important for interpreting observations and inferring the properties of interstellar dust grains. Based on the 993 prism/CLEAR spectra from the James Webb Space Telescope (JWST), we investigate the 0.6–5.3 μm interstellar dust extinction law. We propose a pair method to obtain the reddening curves based only on JWST observed spectra. Most of the high-extinction sources are toward the young star cluster Westerlund 2. The infrared 1.0–5.3 μm reddening curves agree with the power law A  λ  ∝ λ ‑α  well. We determine an average value of α = 1.98 ± 0.15, which is consistent with the average value of the Galaxy. We find that α may be variable and independent of R  V . With the derived α, we convert the reddening curves into the extinction curves and establish the nonparameterized α-dependent extinction curves in the wavelength range of 0.6–5.3 μm. At λ &lt; 1 μm, the derived extinction law is not well described by the parameterized power-law-type curve. Our nonparameterized α-dependent extinction curves are suitable for the extinction correction of JWST-based photometry and spectra measurements at 0.6–5.3 μm. We also provide the extinction coefficients for the JWST NIRCam bandpasses with different α.

Keywords: Interstellar dust extinction, Reddening law, Interstellar reddening, Interstellar extinction, Star clusters
Effects of Type Ia Supernovae Absolute Magnitude Priors on the Hubble Constant Value. We systematically explore the influence of the prior of the peak absolute magnitude (M) of Type Ia supernovae (SNe Ia) on the measurement of the Hubble constant (H 0) from SNe Ia observations. We consider five different data-motivated M priors, representing varying levels of dispersion, and assume the spatially flat ΛCDM cosmological model. Different M priors lead to relative changes in the mean values of H 0 from 2% to 7%. Loose priors on M yield H 0 estimates consistent with both the Planck 2018 result and the SH0ES result at the 68% confidence level. We also examine the potential impact of peculiar velocity subtraction on the value of H 0 and show that it is insignificant for the SNe Ia observations with redshift z &gt; 0.01 used in our analyses. We also repeat the analysis in the cosmography model and find very similar results. This suggests that our results are robust and model independent.

Keywords: Cosmology, Observational cosmology, Hubble constant, Cosmological parameters
The Effect of Fast Solar Wind on Ion Distribution Downstream of Earth's Bow Shock. The solar wind gets thermalized and compressed when crossing a planetary bow shock, forming the magnetosheath. The angle between the upstream magnetic field and the shock normal vector separates the quasi-parallel from the quasi-perpendicular magnetosheath, significantly influencing the physical conditions in these regions. A reliable classification between both magnetosheath regions is of utmost importance since different phenomena and physical processes take place on each. The complexity of this classification is increased due to the origin and variability of the solar wind. Using measurements from the Time History of Events and Macroscale Interactions during Substorms mission and OMNI data between 2008 and 2023, we demonstrate the importance of magnetosheath classification across various solar wind plasma origins. We focus on investigating the ion energy fluxes in the high-energy range for each solar wind type, which typically serves as an indicator for foreshock activity and thus separating the quasi-parallel from quasi-perpendicular magnetosheath. Dividing the data set into different regimes reveals that fast solar wind plasma originating from coronal holes causes exceptionally high-energy ion fluxes even in the quasi-perpendicular environment. This stands in stark contrast to all other solar wind types, highlighting that magnetosheath classification is inherently biased if not all types of solar wind are considered in the classification. Combining knowledge of solar wind origins and structures with shock and magnetosheath research thus contributes to an improved magnetosheath characterization. This is particularly valuable in big-data machine-learning applications within heliophysics, which requires clean and verified data sets for optimal performance.

Keywords: Interplanetary medium, Space plasmas, Heliosphere, Fast solar wind, Plasma physics, Shocks, Solar wind, Planetary bow shocks, Plasma astrophysics, Space weather, Solar-terrestrial interactions, Solar coronal holes
Which Black Hole Is Spinning? Probing the Origin of Black Hole Spin with Gravitational Waves. Theoretical studies of angular momentum transport suggest that isolated stellar-mass black holes are born with negligible dimensionless spin magnitudes χ ≲ 0.01. However, recent gravitational-wave observations indicate ≳40% of binary black hole systems contain at least one black hole with a nonnegligible spin magnitude. One explanation is that the firstborn black hole spins up the stellar core of what will become the second-born black hole through tidal interactions. Typically, the second-born black hole is the "secondary" (less massive) black hole though it may become the "primary" (more massive) black hole through a process known as mass-ratio reversal. We investigate this hypothesis by analyzing data from the third gravitational-wave transient catalog using a "single-spin" framework in which only one black hole may spin in any given binary. Given this assumption, we show that at least 28% (90% credibility) of the LIGO–Virgo–KAGRA binaries contain a primary with significant spin, possibly indicative of mass-ratio reversal. We find no evidence for binaries that contain a secondary with significant spin. However, the single-spin framework is moderately disfavored (natural log Bayes factor $\mathrm{ln}{ \mathcal B }=3.1$ ) when compared to a model that allows both black holes to spin. If future studies can firmly establish that most merging binaries contain two spinning black holes, it may call into question our understanding of formation mechanisms for binary black holes or the efficiency of angular momentum transport in black hole progenitors.

Keywords: Gravitational wave astronomy, Gravitational waves, Black holes, Compact objects
A Relativistic Double Neutron Star Binary PSR J1846-0513. We report the timing analysis of PSR J1846‑0513, a pulsar discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in Commensal Radio Astronomy FAST Survey. The pulsar possesses a spin period of 23.36 ms and a spin-down rate ( ) of 1.0106(3) × 10‑18 s s‑1, and it is located in an eccentric orbit (e ∼0.208) with an orbital period of 0.61 days. The characteristic age and surface magnetic field of the pulsar are found to be 366.62 Myr and 4.9178 × 109 G, respectively, indicating that it is a recycled pulsar. Using over two years of timing data, we measure the periastron advance   = 0.8956(8) deg yr‑1. By assuming that this effect is purely relativistic, we have estimated the total mass M = 2.6287(35)M ⊙ and obtained an upper limit for the pulsar mass and a lower limit for the companion's mass. Our results indicate that this is a double neutron star system.

Keywords: Binary pulsars, Pulsars
Modeling Ion Acceleration and Transport in Corotating Interaction Regions: The Mass-to-charge Ratio Dependence of the Particle Spectrum. We investigate the role of perpendicular diffusion in shaping the energetic ion spectrum in corotating interaction regions (CIRs), focusing on its mass-to-charge (A/Q) ratio dependence. We simulate a synthetic CIR using the EUropean Heliospheric FORecasting Information Asset and model the subsequent ion acceleration and transport by solving the focused transport equation incorporating both parallel and perpendicular diffusion. Our results reveal distinct differences in ion spectra between scenarios with and without perpendicular diffusion. In the absence of perpendicular diffusion, ion spectra near CIRs show a strong (A/Q) ϵ  dependence with ϵ depending on the turbulence spectral index, agreeing with theoretical predictions. In contrast, the incorporation of perpendicular diffusion, characterized by a weak A/Q dependence, leads to similar spectra for different ion species. This qualitatively agrees with observations of energetic particles in CIRs.

Keywords: Solar energetic particles, Interplanetary particle acceleration, Solar wind, Corotating streams
What Powered the Kilonova-like Emission after GRB 230307A in the Framework of a Neutron Star–White Dwarf Merger?. The second brightest gamma-ray burst, GRB 230307A (with a duration T 90 ∼ 40 s), exhibited characteristics indicative of a magnetar engine during the prompt emission phase. Notably, a suspected kilonova was identified in its follow-up optical and infrared observations. Here we propose that the origin of GRB 230307A is a neutron star–white dwarf (NS–WD) merger as this could naturally explain the long duration and the large physical offset from the center of its host galaxy. In the framework of such an NS–WD merger event, the late-time kilonova-like emission is very likely to be powered by the spin-down of the magnetar and the radioactive decay of 56Ni, rather than by the decay of r-process elements as these heavy elements may not easily be synthesized in an NS-WD merger. It is demonstrated that the above scenario can be supported by our fit to the late-time observational data, where a mass of ∼10‑3 M ⊙ 56Ni is involved in the ejecta of a mass of ∼0.1 M ⊙. Particularly, the magnetar parameters required by the fit are consistent with those derived from the early X-ray observation.

Keywords: Gamma-ray bursts
Remarkably Compact Quiescent Candidates at 3 &lt; z &lt; 5 in JWST-CEERS. In this Letter, we measure the rest-frame optical and near-infrared sizes of 10 quiescent candidates at 3 &lt; z &lt; 5, first reported by Carnall et al. We use James Webb Space Telescope Near-Infrared Camera F277W and F444W imaging obtained through the public CEERS Early Release Science program and imcascade, an astronomical fitting code that utilizes multi-Gaussian expansion, to carry out our size measurements. When compared to the extrapolation of rest-optical size–mass relations for quiescent galaxies at lower redshift, 8 out of 10 candidates in our sample (80%) are on average more compact by ∼40%. A total of 7 out of 10 candidates (70%) exhibit rest-frame infrared sizes ∼10% smaller than rest-frame optical sizes, indicative of negative color gradients. Two candidates (20%) have rest-frame infrared sizes ∼1.4× larger than rest-frame optical sizes; one of these candidates exhibits signs of ongoing or residual star formation, suggesting this galaxy may not be fully quenched. The remaining candidate is unresolved in both filters, which may indicate an active galactic nucleus. Strikingly, we observe three of the most massive galaxies in the sample (log(M ⋆/M ⊙) = 10.74–10.95) are extremely compact, with effective radii ∼0.7 kpc. Our findings provide no indication that the size evolution relation flattens out, and may indicate that the size evolution of quiescent galaxies is steeper than previously anticipated beyond z &gt; 3.

Keywords: Galaxy evolution, Galaxy formation, Quenched galaxies, Astronomical location
X-Ray Diagnostics of Cassiopeia A's "Green Monster": Evidence for Dense Shocked Circumstellar Plasma. The recent survey of the core-collapse supernova remnant Cassiopeia A (Cas A) with the MIRI instrument on board the James Webb Space Telescope (JWST) revealed a large structure in the interior region, referred to as the "Green Monster." Although its location suggests that it is an ejecta structure, the infrared properties of the "Green Monster" hint at a circumstellar medium (CSM) origin. In this companion paper to the JWST Cas A paper, we investigate the filamentary X-ray structures associated with the "Green Monster" using Chandra X-ray Observatory data. We extracted spectra along the "Green Monster" as well as from shocked CSM regions. Both the extracted spectra and a principal component analysis show that the "Green Monster" emission properties are similar to those of the shocked CSM. The spectra are well fit by a model consisting of a combination of a nonequilibrium ionization model and a power-law component, modified by Galactic absorption. All the "Green Monster" spectra show a blueshift corresponding to a radial velocity of around ‑2300 km s‑1, suggesting that the structure is on the near side of Cas A. The ionization age is around n e t ≈ 1.5 × 1011 cm‑3 s. This translates into a preshock density of ∼12 cm‑3, higher than previous estimates of the unshocked CSM. The relatively high n e t and relatively low radial velocity suggest that this structure has a relatively high density compared to other shocked CSM plasma. This analysis provides yet another piece of evidence that the CSM around Cas A's progenitor was not that of a smooth steady wind profile.

Keywords: Supernova remnants, Circumstellar matter, X-ray astronomy