Sazuna/UAT_keywords huggingface dataset:
The Astrophysical Distance Scale. III. Distance to the Local Group Galaxy WLM Using Multiwavelength Observations of the Tip of the Red Giant Branch, Cepheids, and JAGB Stars. The local determination of the Hubble constant sits at a crossroad. Current estimates of the local expansion rate of the universe differ by about 1.7σ, derived from the Cepheid- and TRGB-based calibrations, applied to Type Ia supernovae. To help elucidate possible sources of systematic error causing the tension, we show in this study the recently developed distance indicator, the J-region Asymptotic Giant Branch (JAGB) method, can serve as an independent cross-check and comparison with other local distance indicators. Furthermore, we make the case that the JAGB method has substantial potential as an independent, precise, and accurate calibrator of Type Ia supernovae for the determination of H0. Using the Local Group galaxy Wolf-Lundmark-Melotte (WLM), we present distance comparisons between the JAGB method, a TRGB measurement at near-infrared (JHK) wavelengths, a TRGB measurement in the optical I band, and a multiwavelength Cepheid period-luminosity relation determination. We find $\begin{eqnarray*}\begin{array}{rcl}{\mu }_{0}\,(\mathrm{JAGB}) &amp; = &amp; 24.97\pm 0.02\ (\mathrm{stat})\pm 0.04\ (\mathrm{sys})\ \mathrm{mag}\\ {\mu }_{0}\,({\mathrm{TRGB}}_{\mathrm{NIR}}) &amp; = &amp; 24.98\pm 0.04\ (\mathrm{stat})\pm 0.07\ (\mathrm{sys})\ \mathrm{mag}\\ {\mu }_{0}\,({\mathrm{TRGB}}_{{\rm{F}}814{\rm{W}}}) &amp; = &amp; 24.93\pm 0.02\ (\mathrm{stat})\pm 0.06\ (\mathrm{sys})\ \mathrm{mag}\\ {\mu }_{0}\,(\mathrm{Cepheids}) &amp; = &amp; 24.98\pm 0.03\ (\mathrm{stat})\pm 0.04\ (\mathrm{sys})\ \mathrm{mag}.\end{array}\end{eqnarray*}$. All four methods are in good agreement, confirming the local self-consistency of the four distance scales at the 3% level and adding confidence that the JAGB method is as accurate and as precise a distance indicator as either of the other three astrophysically based methods.

Keywords: Carbon stars, Observational cosmology, Distance indicators, Hubble constant, Asymptotic giant branch stars, Cepheid variable stars, Population II stars
Spherical Shocks in a Steep Density Gradient of Expanding Media. We study the propagation of a Newtonian shock in a spherically symmetric, homologously expanding ejecta. We focus on media with a steep power-law density profile of the form ρ ∝ t-3v-α, with α &gt; 5, where v is the velocity of the expanding medium and t is time. Such profiles are expected in the leading edge of supernovae ejecta and sub-relativistic outflows from binary neutron star mergers. We find that such shocks always accelerate in the lab frame and lose causal contact with the bulk of the driver gas, owing to the steep density profile. However, the prolonged shock evolution exhibits two distinct pathways: In one, the shock strength diminishes with time until the shock eventually dies out. In the other, the shock strength steadily increases, and the solution approaches the self-similar solution that a shock is a static medium. By mapping the parameter space of shock solutions, we find that the evolutionary pathways are dictated by α and by the initial ratio between the shock velocity and the local upstream velocity. We find that for α &lt; ωc (ωc ≈ 8), the shock always decays, and that for α &gt; ωc, the shock may decay or grow stronger depending on the initial value of the velocity ratio. These two branches bifurcate from a self-similar solution derived analytically for a constant velocity ratio. We analyze properties of the solutions that may have an impact on the observational signatures of such systems, and assess the conditions required for decaying shocks to break out from a finite medium.

Keywords: Gamma-ray bursts, Core-collapse supernovae, Hydrodynamics, Gravitational wave sources, Shocks, Astrophysical fluid dynamics, Supernova dynamics
From Haloes to Galaxies. II. The Fundamental Relations in Star Formation and Quenching. Star formation and quenching are two of the most important processes in galaxy formation and evolution. We explore in the local universe the interrelationships among key integrated galaxy properties, including stellar mass M*, star formation rate (SFR), specific SFR (sSFR), molecular gas mass ${M}_{{{\rm{H}}}_{2}}$ , star formation efficiency (SFE) of the molecular gas, and the molecular gas to stellar mass ratio μ. We aim to identify the most fundamental scaling relations among these key galaxy properties and their interrelationships. We show that the integrated ${M}_{{{\rm{H}}}_{2}}$ -SFR, SFR-M*, and ${M}_{{{\rm{H}}}_{2}}$ -M* relations can be simply transformed from the μ-sSFR, SFE-μ, and SFE-sSFR relations, respectively. The transformation, in principle, can increase or decrease the scatter of each relation. Interestingly, we find that the latter three relations all have significantly smaller scatter than the corresponding former three. We show that the probability to achieve the observed small scatter by accident is extremely close to zero. This suggests that the smaller scatters of the latter three relations are driven by a more universal physical connection among these quantities. We then show that the large scatters in the former relations are due to their systematic dependence on other galaxy properties, and on the star formation and quenching process. We propose the sSFR-μ-SFE relation as the fundamental formation relation (FFR), which governs the star formation and quenching process and provides a simple framework to study galaxy evolution. Other scaling relations, including the integrated Kennicutt-Schmidt law, star-forming main sequence, and molecular gas main sequence, can all be derived from the FFR.

Keywords: Galaxy formation, Star formation, Galaxy evolution, Interstellar medium
An X-Ray Study of the White Dwarf Binary AR Scorpii. We report a study of X-ray emission from the white dwarf/M-type star binary system AR Scorpii using archival data taken in 2016-2020. It has been known that the X-ray emission is dominated by optically thin thermal plasma emission and its flux level varies significantly over the orbital phase. The X-ray emission also contains a component that modulates with the beat frequency between the white dwarf's spin frequency and orbital frequency. In this new analysis, the 2020 data taken by NICER shows that the X-ray emission modulates with the spin frequency as well as with the beat frequency, indicating that part of the X-ray emission comes from the white dwarf's magnetosphere. It is found that the signal of the spin frequency appears only at a specific orbital phase, while the beat signal appears over the orbital phase. We interpret the X-ray emission modulating with the spin frequency and the beat frequency as a result of synchrotron emission from electrons with smaller and larger pitch angles, respectively. In the long-term evolution, the beat pulse profile averaged over the orbital phase changes from a single-peak structure in 2016/2018 to a double-peak structure in 2020. The observed X-ray flux levels measured in 2016/2017 are higher than those measured in 2018/2020. The plasma temperature and the amplitude of the orbital waveform might vary with time too. These results indicate that the X-ray emission from AR Scorpii evolves on a timescale of years. This long-term evolution would be explained by a superorbital modulation related to, for example, a precession of the white dwarf or a fluctuation of the system related to the activity of the companion star.

Keywords: Non-thermal radiation sources, White dwarf stars, X-ray binary stars, Binary stars
Statistics of the Chemical Composition of Solar Analog Stars and Links to Planet Formation. The Sun has been found to be depleted in refractory (rock-forming) elements relative to nearby solar analogs, suggesting a potential indicator of planet formation. Given the small amplitude of the depletion, previous analyses have primarily relied on high signal-to-noise stellar spectra and a strictly differential approach to determine elemental abundances. We present an alternative, likelihood-based approach that can be applied to much larger samples of stars with lower precision abundance determinations. We utilize measurements of about 1700 solar analogs from the Apache Point Observatory Galactic Evolution Experiment (APOGEE-2) and the APOGEE Stellar Parameter and Chemical Abundance Pipeline (ASPCAP DR16). By developing a hierarchical mixture model for the data, we place constraints on the statistical properties of the elemental abundances, including correlations with condensation temperature and the fraction of stars with refractory element depletions. We find evidence for two distinct populations: a depleted population of stars that makes up the majority of solar analogs including the Sun, and a not-depleted population that makes up between ∼10% and 30% of our sample. We find correlations with condensation temperature generally in agreement with higher precision surveys of a smaller sample of stars. Such trends, if robustly linked to the formation of planetary systems, provide a means to connect stellar chemical abundance patterns to planetary systems over large samples of Milky Way stars.

Keywords: Solar analogs, Stellar abundances, The Sun, Chemical abundances, Planetary system formation
Systematic Study of Acceleration Efficiency in Young Supernova Remnants with Nonthermal X-Ray Observations. Cutoff energy in a synchrotron radiation spectrum of a supernova remnant (SNR) contains a key parameter of ongoing particle acceleration. We systematically analyze 11 young SNRs, including all historical SNRs, to measure the cutoff energy, thus shedding light on the nature of particle acceleration at the early stage of SNR evolution. The nonthermal (synchrotron) dominated spectra in filament-like outer rims are selectively extracted and used for spectral fitting because our model assumes that accelerated electrons are concentrated in the vicinity of the shock front owing to synchrotron cooling. The cutoff energy parameter (ϵ0) and shock speed (vsh) are related as ${\varepsilon }_{0}\propto {v}_{\mathrm{sh}}^{2}{\eta }^{-1}$ with a Bohm factor of η. Five SNRs provide us with spatially resolved ϵ0-vsh plots across the remnants, indicating a variety of particle acceleration. With all SNRs considered together, the systematic tendency of η clarifies a correlation between η and an age of t (or an expansion parameter of m) as η ∝ t-0.4 (η ∝ m4). This might be interpreted as the magnetic field becomes more turbulent and self-generated, as particles are accelerated at a greater rate with time. The maximum energy achieved in SNRs can be higher if we consider the newly observed time dependence on η.

Keywords: Supernova remnants, Galactic cosmic rays, Non-thermal radiation sources, Interstellar medium, X-ray sources, Cosmic rays
Generation of Modern Satellite Data from Galileo Sunspot Drawings in 1612 by Deep Learning. Historical sunspot drawings are very important resources for understanding past solar activity. We generate solar magnetograms and EUV images from Galileo sunspot drawings using a deep learning model based on conditional generative adversarial networks. We train the model using pairs of sunspot drawings from the Mount Wilson Observatory and their corresponding magnetograms (or UV/EUV images) from 2011 to 2015 except for every June and December by the Solar Dynamic Observatory satellite. We evaluate the model by comparing pairs of actual magnetograms (or UV/EUV images) and the corresponding AI-generated ones in June and December. Our results show that bipolar structures of the AI-generated magnetograms are consistent with those of the original ones and their unsigned magnetic fluxes (or intensities) are consistent with those of the original ones. Applying this model to the Galileo sunspot drawings in 1612, we generate Helioseismic and Magnetic Imager-like magnetograms and Atmospheric Imaging Assembly-like EUV images of the sunspots. We hope that the EUV intensities can be used for estimating solar EUV irradiance at long-term historical times.

Keywords: The Sun, Sunspots, Solar active regions, Solar magnetic fields, Sunspot cycle
Deciphering the 3D Orion Nebula. II. A Low Ionization Region of Multiple Velocity Components Southwest of θ<SUP>1</SUP> Ori C Confounds Interpretation of Low Velocity Resolution Studies of Temperature, Density, and Abundance. We establish that there are two velocity systems along lines of sight that contribute to the emission-line spectrum of the brightest parts of the Orion Nebula. These overlie the Orion-S embedded molecular cloud southwest of the dominant ionizing star (θ1 Ori C). Examination of 10 × 10″ samples of high spectral resolution emission-line spectra of this region reveals it to be of low ionization, with velocities and ionization different from the central part of the nebula. These properties jeopardize earlier determinations of abundance and physical conditions since they indicate that this region is much more complex than has been assumed in analyzing earlier spectroscopic studies and argue for use of very high spectral resolution or known simple regions in future studies.

Keywords: H II regions
Modeling Light Curves of Bipolar Core Collapse Supernovae from the Equatorial Plane. We use the two-components bipolar toy model of core collapse supernova (CCSN) ejecta to fit the rapid decline from maximum luminosity in the light curve of the type IIb CCSN SN 2018gk (ASASSN-18am). In this toy model we use a template light curve from a different CCSN that is similar to SN 2018gk, but that has no rapid drop in its light curve. The bipolar morphology that we model with a polar ejecta and an equatorial ejecta increases the maximum luminosity and causes a steeper decline for an equatorial observer, relative to a similar spherical explosion. The total energy and mass of our toy model for SN 2018gk are ${E}_{\mathrm{SN}}=5\times {10}^{51}\,\mathrm{erg}$ and ${M}_{\mathrm{SN}}=2.7{M}_{\odot }$ . This explosion energy is more than what a neutrino driven explosion mechanism can supply, implying that jets exploded SN 2018gk. These energetic jets likely shaped the ejecta to a bipolar morphology, as our toy model requires. We crudely estimate that f ≈ 2%-5% of all CCSNe show this behavior, most being hydrogen deficient (stripped-envelope) CCSNe, as we observe them from the equatorial plane. We estimate the overall fraction of CCSNe that have a pronounced bipolar morphology to be fbip ≈ 5%-15% of all CCSNe.

Keywords: Stellar jets, Supernovae
Model-independently Calibrating the Luminosity Correlations of Gamma-Ray Bursts Using Deep Learning. Gamma-ray bursts (GRBs) detected at high redshift can be used to trace the Hubble diagram of the universe. However, the distance calibration of GRBs is not as easy as that of SNe Ia. For the calibration method based on the empirical luminosity correlations, there is an underlying assumption that the correlations should be universal over the whole redshift range. In this paper, we investigate the possible redshift dependence of six luminosity correlations with a completely model-independent deep-learning method. We construct a network combining the recurrent neural networks (RNN) and the Bayesian neural networks (BNN), where RNN is used to reconstruct the distance-redshift relation by training the network with the Pantheon compilation, and BNN is used to calculate the uncertainty of the reconstruction. Using the reconstructed distance-redshift relation of Pantheon, we test the redshift dependence of six luminosity correlations by dividing the full GRB sample into two subsamples (low-z and high-z subsamples), and find that only the Ep - Eγ relation has no evidence for redshift dependence. We use the Ep - Eγ relation to calibrate GRBs, and the calibrated GRBs give tight constraints on the flat ΛCDM model, with the best-fitting parameter ${{\rm{\Omega }}}_{{\rm{M}}}={0.307}_{-0.073}^{+0.065}$ .

Keywords: Cosmology, Distance measure, Gamma-ray bursts
FIR-luminous [C II] Emitters in the ALMA-SCUBA-2 COSMOS Survey (AS2COSMOS): The Nature of Submillimeter Galaxies in a 10 Comoving Megaparsec-scale Structure at z ∼ 4.6. We report the discovery of a 10 comoving megaparsec (cMpc)-scale structure traced by massive submillimeter galaxies (SMGs) at z ∼ 4.6. These galaxies are selected from an emission line search of ALMA Band 7 observations targeting 184 luminous submillimeter sources (S850μm ≥ 6.2 mJy) across 1.6 degrees2 in the COSMOS field. We identify four [C II] emitting SMGs and two probable [C II] emitting SMG candidates at z = 4.60-4.64 with velocity-integrated signal-to-noise ratio of S/N &gt; 8. Four of the six emitters are near-infrared blank SMGs. After excluding one SMG whose emission line is falling at the edge of the spectral window, all galaxies show clear velocity gradients along the major axes that are consistent with rotating gas disks. The estimated rotation velocities of the disks are 330-550 km s-1 and the inferred host dark-matter halo masses are ∼2-8 × 1012 M☉. From their estimated halo masses and [C II] luminosity function, we suggest that these galaxies have a high (50%-100%) duty cycle and high (∼0.1) baryon conversion efficiency (SFR relative to baryon accretion rate), and that they contribute ≃2% to the total star formation rate density at z = 4.6. These SMGs are concentrated within just 0.3% of the full survey volume, suggesting they are strongly clustered. The extent of this structure and the individual halo masses suggest that these SMGs will likely evolve into members of a ∼1015 M☉ cluster at z = 0. This survey reveals a synchronized dusty starburst in massive halos at z &gt; 4, which could be driven by mergers or fed by smooth gas accretion.

Keywords: Galaxy formation, High-redshift galaxy clusters, Galaxy environments, Galaxy evolution, Submillimeter astronomy
Spin Parity of Spiral Galaxies. III. Dipole Analysis of the Distribution of SDSS Spirals with 3D Random Walk Simulations. Observation has not yet determined whether the distribution of spin vectors of galaxies is truly random. It is unclear whether is there any large-scale symmetry-breaking in the distribution of the vorticity field in the universe. Here, we present a formulation to evaluate the dipole component Dmax of the observed spin distribution, whose statistical significance σD can be calibrated by the expected amplitude for 3D random walk (random flight) simulations. We apply this formulation to evaluate the dipole component in the distribution of Sloan Digital Sky Survey (SDSS) spirals. Shamir published a catalog of spiral galaxies from the SDSS DR8, classifying them with his pattern recognition tool into clockwise and counterclockwise (Z-spiral and S-spiral, respectively). He found significant photometric asymmetry in their distribution. We have confirmed that this sample provides dipole asymmetry up to a level of σD = 4.00. However, we also found that the catalog contains a significant number of multiple entries of the same galaxies. After removing the duplicated entries, the number of samples shrunk considerably to 45%. The actual dipole asymmetry observed for the "cleaned" catalog is quite modest, σD = 0.29. We conclude that SDSS data alone do not support the presence of a large-scale symmetry-breaking in the spin vector distribution of galaxies in the local universe. The data are compatible with a random distribution.

Keywords: Galaxy formation, Spiral galaxies, Galaxy rotation, Cosmic anisotropy, Catalogs
A Luminous Quasar at Redshift 7.642. Distant quasars are unique tracers to study the formation of the earliest supermassive black holes (SMBHs) and the history of cosmic reionization. Despite extensive efforts, only two quasars have been found at z ≥ 7.5, due to a combination of their low spatial density and the high contamination rate in quasar selection. We report the discovery of a luminous quasar at z = 7.642, J0313-1806, the most distant quasar yet known. This quasar has a bolometric luminosity of 3.6 × 1013L☉. Deep spectroscopic observations reveal a SMBH with a mass of (1.6 ± 0.4) × 109 M☉ in this quasar. The existence of such a massive SMBH just ∼670 million years after the big bang challenges significantly theoretical models of SMBH growth. In addition, the quasar spectrum exhibits strong broad absorption line (BAL) features in C IV and Si IV, with a maximum velocity close to 20% of the speed of light. The relativistic BAL features, combined with a strongly blueshifted C IV emission line, indicate that there is a strong active galactic nucleus (AGN)-driven outflow in this system. Atacama Large Millimeter/submillimeter Array observations detect the dust continuum and [C II] emission from the quasar host galaxy, yielding an accurate redshift of 7.6423 ± 0.0013 and suggesting that the quasar is hosted by an intensely star-forming galaxy, with a star formation rate of ∼200 M☉ yr-1 and a dust mass of ∼7 × 107 M☉. Follow-up observations of this reionization-era BAL quasar will provide a powerful probe of the effects of AGN feedback on the growth of the earliest massive galaxies.

Keywords: Supermassive black holes, Early universe, Broad-absorption line quasar, Quasars
Turbulence and Particle Acceleration in Shearing Flows. We explore constraints imposed by shear-driven instabilities on the acceleration of energetic particles in relativistic shearing flows. We show that shearing layers in large-scale AGN jets are likely to encompass a sizeable fraction (≳0.1) of the jet radius, requiring seed injection of GeV electrons for efficient acceleration. While the diffusion process may depend on predeveloped turbulence if injection occurs at higher energies, electron acceleration to PeV and proton acceleration to EeV energies appears possible within the constraints imposed by jet stability.

Keywords: Radio jets, High energy astrophysics, Relativistic jets, Active galactic nuclei, Non-thermal radiation sources
Deep Optical Observations Contemporaneous with Emission from the Periodic FRB 180916.J0158+65. We present deep Apache Point Observatory optical observations within seconds of radio emission from the periodic fast radio burst (FRB) 180916.J0158+65 obtained on 2020 September 3. FRB 180916.J0158+65 is located in a nearby spiral galaxy 150 Mpc away and has an "active phase" with a well-measured period of approximately 16.3 days. Targeting the FRB at the peak of its expected active phase and during a recent 30 minute observing window by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) in which a radio burst was detected, we did not detect any transient optical emission at ${m}_{i}$ ≈ 24.7 mag (3σ) from 2.2 to 1938.1 s after the burst arrival time in optical bands (corrected for dispersion). Comparing our limiting magnitudes to models of a synchrotron maser formed in the circumburst environment of FRB 180916+J0158.65, we constrain scenarios where the burst energy was $\gt {10}^{44}$ erg and the circumburst density was &gt;104 cm-3.

Keywords: Radio bursts, Transient sources, Radio transient sources