Sazuna/UAT_keywords huggingface dataset:
Magnetar Giant Flare Origin for GRB 210410A?. In general, giant flares (GFs) produced by magnetars have a very short-hard initial spike that is followed by a weak oscillatory phase. GFs from a nearby galaxy would appear as cosmic short-hard gamma-ray bursts (GRBs), such as GRB 200415A. In this paper, we search for GF-originated bursts in the Fermi GRB category and report GRB 210410A, which is presented with a very short-hard spike followed by an extended tail emission. In the E p,z  - E iso plane, GRB 210410A with a duration of T 90 ~ 48 s differs from long GRBs, might be classified as a short GRB with a redshift of z ~ 0.28, and could be regarded as a GF with a distance of ~2.7 Mpc. Here, E p,z , E iso, and L iso denote the rest-frame peak photon energy, the isotropic energy, and the isotropic luminosity of the burst, respectively. The radiation spectrum of GRB 210410A, similar to that of GRB 200415A, can be well fitted with a non-dissipative photospheric emission. However, GRB 210410A in the E p,z  - L iso plane is beyond the death line of cosmic GRBs for non-dissipated photospheric emission with a general initial size of the fireball. Since the E p,z  - L iso relation of GFs is far beyond the death line of cosmic GRBs, GRB 210410A may have originated from the same channel that produces GFs. We also perform the analysis and discuss both the highest photon energy event (4.2 GeV) and the extended tail emission in this burst.

Keywords: Magnetars, Gamma-ray bursts
The Properties of Small Magnetic Flux Ropes inside the Solar Wind Come from Coronal Holes, Active Regions, and Quiet Sun. The origination and generation mechanisms of small magnetic flux ropes (SMFRs), which are important structures in solar wind, are not clearly known. In the present study, 1993 SMFRs immersed in coronal holes, active regions, and quiet-Sun solar wind are analyzed and compared. We find that the properties of SMFRs immersed in three types of solar wind are significantly different. The SMFRs are further classified into hot-SMFRs, cold-SMFRs, and normal-SMFRs, according to whether the O7+/O6+ is 30% elevated or dropped inside SMFRs as compared with background solar wind. Our studies show that the parameters of normal-SMFRs are similar to background in all three types of solar wind. The properties of hot-SMFRs and cold-SMFRs seem to be lying in two extremes. Statistically, the hot-SMFRs (cold-SMFRs) are associated with longer (shorter) duration, lower (higher) speeds and proton temperatures, higher (lower) charge states, helium abundance, and first ionization potential bias as compared with normal-SMFRs and background solar wind. The anticorrelations between speed and O7+/O6+ inside hot-SMFRs (normal-SMFRs) are different from (similar to) those in background solar wind. Most hot-SMFRs and cold-SMFRs should come from the Sun. Hot-SMFRs may come from streamers associated with plasma blobs and/or small-scale activities on the Sun. Cold-SMFRs may be accompanied by small-scale eruptions with lower-temperature materials. Both hot-SMFRs and cold-SMFRs could also be formed by magnetic erosions of interplanetary coronal mass ejections that do not contain or do contain cold-filament materials. The characteristics of normal-SMFRs can be explained reasonably by the two originations, both from the Sun and generated in the heliosphere.

Keywords: Solar cycle, Solar wind, Interplanetary magnetic fields
Surrogate Forward Models for Population Inference on Compact Binary Mergers. Rapidly growing catalogs of compact binary mergers from advanced gravitational wave detectors allow us to explore the astrophysics of massive stellar binaries. Merger observations can constrain the uncertain parameters that describe the underlying processes in the evolution of stars and binary systems in population models. In this paper, we demonstrate that binary black hole populations-in particular, their detection rates, chirp masses, and redshifts-can be used to measure cosmological parameters describing the redshift-dependent star formation rate and metallicity distribution. We present a method that uses artificial neural networks to emulate binary population synthesis computer models, and construct a fast, flexible, parallelizable surrogate model that we use for inference.

Keywords: Gravitational wave astronomy, Stellar mass black holes, Neural networks
Star Formation in the Dwarf Seyfert Galaxy NGC 4395: Evidence for Both AGN and SN Feedback?. We present a detailed multiwavelength study of star formation in the dwarf galaxy NGC 4395, which hosts an active galactic nucleus (AGN). From our observations with the Ultra-Violet Imaging Telescope, we have compiled a catalog of 284 star-forming (SF) regions, out of which we could detect 120 SF regions in Hα observations. Across the entire galaxy, we found the extinction-corrected star formation rate (SFR) in the far ultraviolet (UV) to range from 2.0 × 10-5 M ⊙ yr-1 to 1.5 × 10-2 M ⊙ yr-1 with a median of 3.0 × 10-4 M ⊙ yr-1, and the age to lie in the range of ~1 to 98 Myr with a median of 14 Myr. In Hα we found the SFR to range from 7.2 × 10-6 M ⊙ yr-1 to 2.7 × 10-2 M ⊙ yr-1 with a median of 1.7 × 10-4 M ⊙ yr-1, and the age to lie between 3 to 6 Myr with a median of 5 Myr. The stellar ages derived from Hα show a gradual decline with galactocentric distance. We found three SF regions close to the center of NGC 4395 with high SFRs both from Hα and UV, which could be attributed to feedback effects from the AGN. We also found six other SF regions in one of the spiral arms having higher SFRs. These are very close to supernova remnants, which could have enhanced the SFR locally. We obtained a specific SFR (SFR per unit mass) for the whole galaxy of 4.64 × 10-10 yr-1.

Keywords: Seyfert galaxies, Star formation, Active galactic nuclei, Galaxy photometry, Radio continuum emission
Using Dark Energy Explorers and Machine Learning to Enhance the Hobby-Eberly Telescope Dark Energy Experiment. We present analysis using a citizen science campaign to improve the cosmological measures from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). The goal of HETDEX is to measure the Hubble expansion rate, H(z), and angular diameter distance, D A(z), at z = 2.4, each to percent-level accuracy. This accuracy is determined primarily from the total number of detected Lyα emitters (LAEs), the false positive rate due to noise, and the contamination due to [O II] emitting galaxies. This paper presents the citizen science project, Dark Energy Explorers (https://www.zooniverse.org/projects/erinmc/dark-energy-explorers), with the goal of increasing the number of LAEs and decreasing the number of false positives due to noise and the [O II] galaxies. Initial analysis shows that citizen science is an efficient and effective tool for classification most accurately done by the human eye, especially in combination with unsupervised machine learning. Three aspects from the citizen science campaign that have the most impact are (1) identifying individual problems with detections, (2) providing a clean sample with 100% visual identification above a signal-to-noise cut, and (3) providing labels for machine-learning efforts. Since the end of 2022, Dark Energy Explorers has collected over three and a half million classifications by 11,000 volunteers in over 85 different countries around the world. By incorporating the results of the Dark Energy Explorers, we expect to improve the accuracy on the D A(z) and H(z) parameters at z = 2.″4 by 10%-30%. While the primary goal is to improve on HETDEX, Dark Energy Explorers has already proven to be a uniquely powerful tool for science advancement and increasing accessibility to science worldwide.

Keywords: Cosmology, Dark energy, Astronomy education, Cosmological parameters
A Gaia Data Release 3 View on the Tip of the Red Giant Branch Luminosity. The tip of the red giant branch (TRGB) is a standard candle that can be used to help refine the determination of the Hubble constant. Gaia Data Release 3 (DR3) provides synthetic photometry constructed from low-resolution BP/RP spectra for Milky Way field stars that can be used to directly calibrate the luminosity of the TRGB in the Johnson-Cousins I band, where the TRGB is least sensitive to metallicity. We calibrate the TRGB luminosity using a two-dimensional maximum likelihood algorithm with field stars and Gaia synthetic photometry and parallaxes. For a high-contrast and low-contrast break (characterized by the values of the contrast parameter R or the magnitude of the break β), we find M TRGB  I  = -4.02 and -3.92 mag respectively, or a midpoint of -3.970 ${}_{-0.024}^{+0.042}$ (sys) ± 0.062 (stat) mag. This measurement improves upon the TRGB measurement from Li et al., as the higher precision photometry based on Gaia DR3 allows us to constrain two additional free parameters of the luminosity function. We also investigate the possibility of using Gaia DR3 synthetic photometry to calibrate the TRGB luminosity with ω Centauri, but find evidence of blending within the inner region for cluster member photometry that precludes accurate calibration with Gaia DR3 photometry. We instead provide an updated TRGB measurement of m TRGB  I  = 9.82 ± 0.04 mag in ω Centauri using ground-based photometry from the most recent version of the database described in Stetson et al., which gives M TRGB  I  = -3.97 ± 0.04 (stat) ± 0.10 (sys) mag when tied to the Gaia EDR3 parallax distance from the consensus of Vasiliev &amp; Baumgardt, Soltis et al., and Maíz Apellániz.

Keywords: Red giant tip, Parallax, Field stars, Distance indicators, Hubble constant, Calibration, Absolute magnitude, Maximum likelihood estimation, Milky Way Galaxy
The Interstellar Medium Scaling Relations Using Inner H I and an Application of Estimating Dust Mass. We select a disk-like galaxy sample with observations of the H I, H2, and dust from the Herschel Reference Survey, and derive inner H I masses within the optical radius. We find that the inner gas-to-dust ratio is almost independent of gas-phase metallicity, and confirm that the inner gas mass (H I+H2) shows a tighter relation with dust mass and monochromatic 500 μm luminosity than the integral gas mass. It supports that dust is more closely associated with cospatial cold gas than the overall cold gas. Based on the newly calibrated relationship between inner gas mass and dust mass, we predict dust masses for disk-dominated galaxies from the xCOLD GASS sample. The predicted dust masses show scaling relations consistent with fiducial ones in the literature, supporting their robustness. Additionally, we find that at a given dust mass and star formation rate (SFR), the galactic Wide-field Infrared Explorer W3 luminosities show a significant dependence on the [N II] luminosity and the stellar mass surface density. Such dependence highlights the caveat of using the W3 luminosity as an integral SFR indicator, and is consistent with findings of studies that target star-forming regions in more nearby galaxies and accurately derive dust masses based on mapping-mode spectroscopy.

Keywords: Gas-to-dust ratio, Polycyclic aromatic hydrocarbons, Late-type galaxies, Star formation, Interstellar medium
The Assembly of Black Hole Mass and Luminosity Functions of High-redshift Quasars via Multiple Accretion Episodes. The early evolution of the quasar luminosity function (QLF) and black hole mass function (BHMF) encodes key information on the physics determining the radiative and accretion processes of supermassive black holes (BHs) in high-z quasars. Although the QLF shape has been constrained by recent observations, it remains challenging to develop a theoretical model that explains its redshift evolution associated with BH growth self-consistently. In this study, based on a semianalytical model for the BH formation and growth, we construct the QLF and BHMF of the early BH population that experiences multiple accretion bursts, in each of which a constant Eddington ratio is assigned following a Schechter distribution function. Our best-fit model to reproduce the observed QLF and BHMF at z ≃ 6 suggests that several episodes of moderate super-Eddington accretion occur and each of them lasts for τ ≃ 20-30 Myr. The average duty cycle in super-Eddington phases is ≃15% for massive BHs that reach ≳108 M ⊙ by z ≃ 6, which is nearly twice that of the entire population. We find that the observed Eddington ratio distribution function is skewed to a lognormal shape owing to detection limits of quasar surveys. The predicted redshift evolution of the QLF and BHMF suggests a rapid decay of their number and mass density in a cosmic volume toward z ≳ 6. These results will be unveiled by future deep and wide surveys with the James Webb Space Telescope, Roman Space Telescope, and Euclid.

Keywords: Supermassive black holes, Quasars
One Relation for All Wavelengths: The Far-ultraviolet to Mid-infrared Milky Way Spectroscopic R(V)-dependent Dust Extinction Relationship. Dust extinction is one of the fundamental measurements of dust grain sizes, compositions, and shapes. Most of the wavelength-dependent variations seen in Milky Way extinction are strongly correlated with the single parameter R(V) = A(V)/E(B - V). Existing R(V)-dependent extinction relationships use a mixture of spectroscopic and photometry observations, and hence do not fully capture all the important dust features or continuum variations. Using four existing samples of spectroscopically measured dust extinction curves, we consistently measure the R(V)-dependent extinction relationship spectroscopically from the far-ultraviolet (FUV) to mid-infrared for the first time. Linear fits of A(λ)/A(V) dependent on R(V) are done using a method that fully accounts for their significant and correlated uncertainties. These linear parameters are fit with analytic wavelength-dependent functions to determine the smooth R(V) (2.3-5.6) and wavelength (912 Å-32 μm) dependent extinction relationship. This relationship shows that the FUV rise, 2175 Å bump, and the three broad optical features are dependent on R(V), but the 10 and 20 μm features are not. Existing literature relationships show significant deviations compared to this relationship especially in the FUV and infrared (IR). Extinction curves that clearly deviate from this relationship illustrate that this relationship only describes the average behavior versus R(V). We find tentative evidence that the relationship may not be linear with R(V)-1 especially in the ultraviolet (UV). For the first time, this relationship provides measurements of dust extinction that spectroscopically resolve the continuum and features in the UV, optical, and IR as a function of R(V), enabling detailed studies of dust grain properties and full spectroscopic accounting for the effects of dust extinction on astrophysical objects.

Keywords: Interstellar dust, Interstellar dust extinction, Reddening law, Interstellar reddening, Ultraviolet extinction, Interstellar medium, Interstellar extinction, Spectroscopy, Reddened stars, Milky Way Galaxy
A Generalist, Automated ALFALFA Baryonic Tully-Fisher Relation. The baryonic Tully-Fisher relation (BTFR) has applications in galaxy evolution as a test bed for the galaxy-halo connection and in observational cosmology as a redshift-independent secondary distance indicator. This analysis leverages the 31,000+ galaxy Arecibo Legacy Fast ALFA (Arecibo L-band Feed Array) Survey (ALFALFA) sample-which provides redshifts, velocity widths, and H I content for a large number of gas-bearing galaxies in the local universe-to fit and test an extensive local universe BTFR. The fiducial relation is fit using a 3000-galaxy subsample of ALFALFA, and is shown to be consistent with the full sample. This BTFR is designed to be as inclusive of ALFALFA and comparable samples as possible. Velocity widths measured via an automated method and M  b  proxies extracted from survey data can be uniformly and efficiently measured for other samples, giving this analysis broad applicability. We also investigate the role of sample demographics in determining the best-fit relation. We find that the best-fit relations are changed significantly by changes to the sample mass range and to second order by changes to mass sampling, gas fraction, different stellar mass and velocity width measurements. We use a subset of ALFALFA with demographics that reflect the full sample to measure a robust BTFR slope of 3.30 ± 0.06. We apply this relation and estimate source distances, finding general agreement with flow-model distances as well as average distance uncertainties of ~0.17 dex for the full ALFALFA sample. We demonstrate the utility of these distance estimates by applying them to a sample of sources in the Virgo vicinity, recovering signatures of infall consistent with previous work.

Keywords: Galaxy distances, Spiral galaxies, Galaxy dynamics, H I line emission, Galactic and extragalactic astronomy
Simulated Observations of Star Formation Regions: Infrared Evolution of Globally Collapsing Clouds. A direct comparison between hydrodynamical simulations and observations is needed to improve the physics included in the former and to test biases in the latter. Post-processing radiative transfer and synthetic observations are now the standard way to do this. We report on the first application of the SKIRT radiative-transfer code to simulations of a star-forming cloud. The synthetic observations are then analyzed following traditional observational workflows. We find that in the early stages of the simulation, stellar radiation is inefficient in heating dust to the temperatures that are observed in Galactic clouds, thus the addition of an interstellar radiation field is necessary. The spectral energy distribution of the cloud settles rather quickly after ~3 Myr of evolution from the onset of star formation, but its morphology continues to evolve for ~8 Myr due to the expansion of H II regions and the respective creation of cavities, filaments, and ridges. Modeling synthetic Herschel fluxes with one- or two-component modified blackbodies underestimates total dust masses by a factor of ~2. However, spatially resolved fitting recovers up to about 70% of the intrinsic value. This "missing mass" is located in a very cold dust component with temperatures below 10 K, which does not contribute appreciably to the far-infrared flux. This effect could bias real observations if this dust exists in large amounts. Finally, we tested observational calibrations of the SFR based on infrared fluxes and concluded that they are in agreement when compared to the intrinsic SFR of the simulation averaged over ~100 Myr.

Keywords: Interstellar radiation field, Star forming regions, Computational methods, Interstellar medium, Radiative transfer simulations
High-energy (&gt;40 MeV) Proton Intensity Enhancements Associated with the Passage of Interplanetary Shocks at 1 au. We analyze periods with elevated &gt;40 MeV proton intensities observed near Earth over a time span of 43 yr (1973-2016) that coincide with the passage of interplanetary (IP) shocks. Typically, elevated proton intensities result from large solar energetic particle (SEP) events. The IP shocks observed during these elevated-intensity periods may or may not be related to the origin of the SEP events. By choosing those cases when the shocks can be confidently associated with the solar eruption that generated the SEP event, we analyze the components of these SEP events that are localized in the vicinity of the shock (so-called "energetic storm particles", ESPs), focusing on those events where the ESP component exceeds 40 MeV. We examine the interdependence of these high-energy ESPs with (i) the properties of the solar eruptions that generated the shocks and the SEP events, and (ii) the parameters of the shocks at their arrival at 1 au. The solar eruptions at the origin of the shocks producing &gt;40 MeV proton ESP intensity enhancements are within ±50° longitude of central meridian and are associated with fast coronal mass ejections (plane-of-sky speeds ≳1000 km s-1). The ESP events with the largest &gt;40 MeV proton intensity increases tend to occur when there are structures such as intervening IP coronal mass ejections and other unrelated shocks present in the solar wind through which the shock is propagating. Among the various local shock parameters considered, only the shock speed shows a certain degree of correlation with the observed ESP intensity increase.

Keywords: Solar energetic particles, Interplanetary particle acceleration, Interplanetary shocks
Far-ultraviolet Spectroscopy of Active Galactic Nuclei with ASTROSAT/UVIT. We study accretion disk emission from eight Seyfert 1-1.5 active galactic nuclei (AGN) using far-ultraviolet (FUV) (1300-1800 Å) slitless grating spectra acquired with AstroSat/UVIT. We correct for the Galactic and intrinsic extinction, contamination from the host galaxies, narrow and broad-line regions, Fe II emission, and Balmer continuum, and derive the intrinsic continua. We use Hubble Space Telescope COS/FOS spectra to account for the emission/absorption lines in the low-resolution UVIT spectra. We find generally redder power-law (f  ν  ∝ ν  α ) slopes (α ~ -1.1 to 0.3) in the FUV band than predicted by the standard accretion disk model in the optical/UV band. We fit accretion disk models such as the multitemperature disk blackbody (DISKBB) and relativistic disk (ZKERRBB, OPTXAGNF) models to the observed intrinsic continuum emission. We measure the inner disk temperatures using the DISKBB model for seven AGN. These temperatures in the range ~3.6-5.8 eV are lower than the peak temperatures predicted for standard disks around maximally spinning supermassive black holes accreting at Eddington rates. The inner disks in two AGN, NGC 7469, and Mrk 352, appear to be truncated at ~35-125 and 50-135 r  g , respectively. While our results show that the intrinsic FUV emission from the AGN is consistent with the standard disks, it is possible that UV continua may be affected by the presence of soft X-ray excess emission, X-ray reprocessing, and thermal Comptonization in the hot corona. Joint spectral modeling of simultaneously acquired UV/X-ray data may be necessary to further investigate the nature of accretion disks in AGN.

Keywords: Extragalactic astronomy, Spectral index, Active galactic nuclei, Ultraviolet spectroscopy
The Anatomy of a Turbulent Radiative Mixing Layer: Insights from an Analytic Model with Turbulent Conduction and Viscosity. Turbulent radiative mixing layers (TRMLs) form at the interface of cold, dense gas and hot, diffuse gas in motion with each other. TRMLs are ubiquitous in and around galaxies on a variety of scales, including galactic winds and the circumgalactic medium. They host the intermediate-temperature gases that are efficient in radiative cooling, thus playing a crucial role in controlling the cold gas supply, phase structure, and spectral features of galaxies. In this work, we develop an intuitive analytic 1.5-dimensional model for TRMLs that includes a simple parameterization of the effective turbulent conductivity and viscosity and a piecewise power-law cooling curve. Our analytic model reproduces the mass flux, total cooling, and phase structure of 3D simulations of TRMLs at a fraction of the computational cost. It also reveals essential insights into the physics of TRMLs, particularly the importance of the viscous dissipation of relative kinetic energy in balancing radiative cooling as the shear Mach number approaches unity. This dissipation takes place both in the intermediate-temperature phase, which reduces the enthalpy flux from the hot phase, and in the cold phase, which enhances radiative cooling. Additionally, our model provides a fast and easy way of computing the column density and surface brightness of TRMLs, which can be directly linked to observations.

Keywords: Galactic winds, Galaxy physics, Galactic and extragalactic astronomy, Galaxy evolution, Circumgalactic medium, Galaxies