Sazuna/UAT_keywords huggingface dataset:
Diagonal Ridge Pattern of Different Age Populations Found in Gaia-DR2 with LAMOST Main-sequence Turnoff and OB-type Stars. We revisit the diagonal ridge feature (diagonal distributions in the R, vφ plane) found in Gaia and present a timing analysis for it between Galactocentric distances of R = 7.5 and 12 kpc, using main-sequence turnoff and OB stars selected from the LAMOST Galactic spectroscopic surveys. We recover the ridge pattern in the R-vφ plane color coded by mean radial velocity and find that this feature is presented from very young (OB stars, few hundred megayears) to very old populations (τ = 9-14 Gyr). Meanwhile, some ridge features are also revealed in the metallicity [Fe/H], [α/Fe], and vz distributions. In the LZ, vφ plane, one of the ridge patterns, with constant angular momentum per unit mass, shows variations with different age populations compared. However, the remaining two are relatively stable, implying there might be two kinds of ridge patterns with different dynamical origins and evolutions.

Keywords: Milky Way formation, Milky Way dynamics, Milky Way disk, Milky Way evolution, Milky Way Galaxy
Localization of Compact Binary Sources with Second-generation Gravitational-wave Interferometer Networks. GW170817 began gravitational-wave multimessenger astronomy. However, GW170817 will not be representative of detections in the coming years because typical gravitational-wave sources will be closer the detection horizon, have larger localization regions, and (when present) will have correspondingly weaker electromagnetic emission. In its design state, the gravitational-wave detector network in the mid-2020s will consist of up to five similar-sensitivity second-generation interferometers. The instantaneous sky-coverage by the full network is nearly isotropic, in contrast to the configuration during the first three observing runs. Along with the coverage of the sky, there are also commensurate increases in the average horizon for a given binary mass. We present a realistic set of localizations for binary neutron stars and neutron star-black hole binaries, incorporating intra-network duty cycles and selection effects on the astrophysical distributions. Based on the assumption of an 80% duty cycle, and that two instruments observe a signal above the detection threshold, we anticipate a median of 28 sq. deg. for binary neutron stars, and 50-120 sq. deg. for neutron star-black hole (depending on the population assumed). These distributions have a wide spread, and the best localizations, even for networks with fewer instruments, will have localizations of 1-10 sq. deg. range. The full five instrument network reduces localization regions to a few tens of degrees at worst.

Keywords: Gravitational wave astronomy, Gravitational wave detectors, Gravitational waves, Gravitational wave sources
A New Approach for the Regression of the Center Coordinates and Radius of the Solar Disk Using a Deep Convolutional Neural Network. This paper presents a new approach for the regression of the center coordinates and radius of the solar disk in Hα solar full-disk images by using a Deep Convolutional Neural Network. We use ∼100,000 original Hα solar full-disk images obtained from Huairou Solar Observing Station as the experimental data set. The data set includes two parts: the original image and three numeric values (center coordinates and radius). In order to deal with the uneven distribution of the solar disk position in the original image, we randomly shift the solar disk during image preprocessing. Furthermore, data augmentation is also used to increase the robustness of the model. By evaluating the model with R-square and relative error, the center coordinates and the radius of the solar disk are proved to be effectively regressed. The data sets we constructed and source code are available as open source on GitHub.

Keywords: Regression, Convolutional neural networks, Astronomy data analysis, Solar physics, Solar radius
Starspot Mapping with Adaptive Parallel Tempering. I. Implementation of Computational Code. Starspots are thought to be regions of locally strong magnetic fields, similar to sunspots, and they can generate photometric brightness modulations. To deduce stellar and spot properties, such as spot emergence and decay rates, we implement a computational code for starspot modeling. It is implemented with an adaptive parallel tempering algorithm and an importance sampling algorithm for parameter estimation and model selection in the Bayesian framework. For evaluating the performance of the code, we apply it to synthetic light curves produced with three spots. The light curves are specified in the spot parameters, such as the radii, intensities, latitudes, longitudes, and emergence/decay durations. The spots are circular with specified radii and intensities relative to the photosphere, and the stellar differential rotation coefficient is also included in the light curves. As a result, stellar and spot parameters are uniquely deduced, and the number of spots is correctly determined: the three-spot model is preferable because the model evidence is much greater than that of the two-spot model by orders of magnitude and more than that of the four-spot model by a more modest factor, whereas the light curves are produced to have two or one local minimum during one equatorial rotation period by adjusting the values of longitude. The spot emergence and decay rates can be estimated with error less than an order of magnitude, considering the difference of the number of spots.

Keywords: Starspots, Bayesian statistics, Model selection, Importance sampling, Astrostatistics, Markov chain Monte Carlo
Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548. We present geometric and dynamical modeling of the broad line region (BLR) for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The data set includes photometric and spectroscopic monitoring in the optical and ultraviolet, covering the Hβ, C IV, and Lyα broad emission lines. We find an extended disk-like Hβ BLR with a mixture of near-circular and outflowing gas trajectories, while the C IV and Lyα BLRs are much less extended and resemble shell-like structures. There is clear radial structure in the BLR, with C IV the three lines, we make three independent black hole mass measurements, all of which are consistent. Combining these results gives a joint inference of ${\mathrm{log}}_{10}({M}_{\mathrm{BH}}/{M}_{\odot })={7.64}_{-0.18}^{+0.21}$ . We examine the effect of using the V band instead of the UV continuum light curve on the results and find a size difference that is consistent with the measured UV-optical time lag, but the other structural and kinematic parameters remain unchanged, suggesting that the V band is a suitable proxy for the ionizing continuum when exploring the BLR structure and kinematics. Finally, we compare the Hβ results to similar models of data obtained in 2008 when the active galactic nucleus was at a lower luminosity state. We find that the size of the emitting region increased during this time period, but the geometry and black hole mass remained unchanged, which confirms that the BLR kinematics suitably gauge the gravitational field of the central black hole.

Keywords: Seyfert galaxies, Reverberation mapping, Active galaxies, Active galactic nuclei
Characteristic Mass in Galaxy Quenching: Environmental versus Internal Effects. A clear transition feature of galaxy quenching is identified in the multi-parameter space of stellar mass (M*), bulge-to-total mass ratio (B/Tm), halo mass (Mh) and halo-centric distance (r/r180). For a given halo mass, the characteristic stellar mass ( ${M}_{* ,\mathrm{ch}}$ ) for the transition is about one-fifth of that of the corresponding central galaxy, and almost independent of B/Tm. Once B/Tm is fixed, the quenched fraction of galaxies with ${M}_{* }\lt {M}_{* ,\mathrm{ch}}$ increases with Mh, but decreases with M* in the inner part of halos (r/r180 &lt; 0.5). In the outer part (r/r180 &gt; 0.5), the trend with Mh remains but the correlation with M* is absent or becomes positive. For galaxies above ${M}_{* ,\mathrm{ch}}$ and with B/Tm fixed, the quenched fraction increases with ${M}_{* }$ , but depends only weakly on Mh in both the inner and outer regions. At fixed B/Tm and M*, the quenched fraction increases with decreasing r/r180 for galaxies with ${M}_{* }\lt {M}_{* ,\mathrm{ch}}$ , and depends only weakly on r/r180 for galaxies with ${M}_{* }\gt {M}_{* ,\mathrm{ch}}$ . Our finding provides a physically motivated way to classify galaxies in halos into two classes based on their quenching properties: an "upper class" with ${M}_{* }\gt {M}_{* ,\mathrm{ch}}$ and a "lower class" with ${M}_{* }\lt {M}_{* ,\mathrm{ch}}$ . Environmental quenching is important for "lower class" galaxies, while internal quenching plays the dominating role for the "upper class."

Keywords: Galaxy dark matter halos, Galaxy environments, Galaxy evolution, Galaxy quenching, Galaxies
The CaFe Project: Optical Fe II and Near-infrared Ca II Triplet Emission in Active Galaxies. I. Photoionization Modeling. Optical Fe II emission is a strong feature in quasar spectra originating in the broad-line region (BLR). The difficulty in understanding the complex Fe II pseudo-continuum has led us to search for other reliable, simpler ionic species such as Ca II. In this first part of the series, we confirm the strong correlation between the strengths of two emission features, the optical Fe II and the NIR Ca II, both from observations and photoionization modeling. With the inclusion of an up-to-date compilation of observations with both optical Fe II and NIR Ca II measurements, we span a wider and more extended parameter space and confirm the common origin of these two spectral features with our photoionization models using CLOUDY. Taking into account the effect of dust into our modeling, we constrain the BLR parameter space (primarily in terms of the ionization parameter and local cloud density) as a function of the strengths of Fe II and Ca II emission.

Keywords: Accretion, Supermassive black holes, Quasars, Active galaxies, Scaling relations, Active galactic nuclei, Radiative transfer
CANDELS Meets GSWLC: Evolution of the Relationship between Morphology and Star Formation Since z = 2. Galaxy morphology and its evolution over the cosmic epoch hold important clues for understanding the regulation of star formation (SF). However, studying the relationship between morphology and SF has been hindered by the availability of consistent data at different redshifts. Our sample, combining CANDELS (0.8 &lt; z &lt; 2.5) and the GALEX-SDSS-WISE Legacy Catalog (GSWLC; z ∼ 0), has physical parameters derived using consistent SED fitting with flexible dust attenuation laws. We adopt visual classifications from Kartaltepe et al. and expand them to z ∼ 0 using SDSS images matching the physical resolution of CANDELS rest-frame optical images and deep FUV GALEX images matching the physical resolution of the CANDELS rest-frame FUV images. Our main finding is that disks with SF clumps at z ∼ 0 make a similar fraction (∼15%) of star-forming galaxies as at z ∼ 2. The clumpy disk contribution to the SF budget peaks at z ∼ 1, rather than z ∼ 2, suggesting that the principal epoch of disk assembly continues to lower redshifts. Star-forming spheroids ("blue nuggets"), though less centrally concentrated than quenched spheroids, contribute significantly (∼15%) to the SF budget at z ∼ 1-2, suggesting that compaction precedes quenching. Among green valley and quiescent galaxies, the pure spheroid fraction drops after z ∼ 1, whereas spheroids with disks (S0-like) become dominant. Mergers at or nearing coalescence are enhanced in SFR relative to the main sequence at all redshifts by a factor of ∼2, but contribute ≲5% to the SF budget, with their contribution remaining small above the main sequence.

Keywords: Galaxy formation, Late-type galaxies, Quenched galaxies, Disk galaxies, Galaxy classification systems, Star formation, Galaxy mergers, Galaxy evolution, Galaxy quenching, High-redshift galaxies, Galaxies
The Complete Redshift Distribution of Dusty Star-forming Galaxies from the SPT-SZ Survey. The South Pole Telescope (SPT) has systematically identified 81 high-redshift, strongly gravitationally lensed, dusty star-forming galaxies (DSFGs) in a 2500 square degree cosmological millimeter-wave survey. We present the final spectroscopic redshift survey of this flux-limited (S870 μm &gt; 25 mJy) sample, initially selected at 1.4 mm. The redshift survey was conducted with the Atacama Large Millimeter/submillimeter Array across the 3 mm spectral window, targeting carbon monoxide line emission. By combining these measurements with ancillary data, the SPT sample is now spectroscopically complete, with redshifts spanning 1.9 &lt; z &lt; 6.9 and a median of $z=3.9\pm 0.2$ . We present the millimeter through far-infrared photometry and spectral energy density fits for all sources, along with their inferred intrinsic properties. Comparing the properties of the SPT sources to the unlensed DSFG population, we demonstrate that the SPT-selected DSFGs represent the most extreme infrared-luminous galaxies, even after accounting for strong gravitational lensing. The SPT sources have a median star formation rate of $2.3(2)\times {10}^{3}{M}_{\odot }\,\,{\mathrm{yr}}^{-1}$ and a median dust mass of $1.4(1)\times {10}^{9}{M}_{\odot }$ . However, the inferred gas depletion timescales of the SPT sources are comparable to those of unlensed DSFGs, once redshift is taken into account. This SPT sample contains roughly half of the known spectroscopically confirmed DSFGs at z &gt; 5, making this the largest sample of high-redshift DSFGs to date, and enabling the "high-redshift tail" of extremely luminous DSFGs to be measured. Though galaxy formation models struggle to account for the SPT redshift distribution, the larger sample statistics from this complete and well-defined survey will help inform future theoretical efforts.

Keywords: Interstellar molecules, Early universe, Observational cosmology, Galaxy evolution, High-redshift galaxies
Incompleteness Matters Not: Inference of H<SUB>0</SUB> from Binary Black Hole-Galaxy Cross-correlations. We show how the angular clustering between gravitational-wave (GW) standard sirens and galaxies with known redshifts allows an inference of the Hubble constant regardless of whether the host galaxies of any of these sirens are present in the galaxy catalog. We demonstrate this for the first time with realistic simulations of GW signals from binary black holes in a three-detector network with Advanced LIGO and Advanced Virgo sensitivities. We show that with such a network, the cross-correlation technique can be used to infer the Hubble parameter with a precision of less than 10% (2%) at 90% confidence with 50 (500) sources, even with a 100% incomplete catalog, which does not contain the hosts of any of the GW events. We compare our method with the current state-of-the-art techniques used for the inference of the Hubble parameter from real data. We argue that, if the clustering information is not used explicitly, the inference of H0 from real data is expected to be prior-dominated.

Keywords: Hubble constant, Gravitational waves, Large-scale structure of the universe
Comprehensive Analysis of Magnetospheric Gaps around Kerr Black Holes Using 1D GRPIC Simulations. Spark gaps are likely the source of plasma in active black hole (BH) magnetospheres. In this paper, we present results of 1D general relativistic particle-in-cell simulations of a starved BH magnetosphere with a realistic treatment of inverse-Compton scattering and pair production, for a broad range of conditions, run times longer than in previous studies, and different setups. We find that following the initial discharge, the system undergoes gradual evolution over prolonged time until either restoring the vacuum state or reaching a state of quasiperiodic oscillations, depending on the spectral shape and luminosity of the ambient radiation field. The oscillations occur near the null charge surface in cases where the global magnetospheric current is in the direction defined by the product of the asymptotic Goldreich-Julian charge density and the radial velocity, while they occur near the boundary of the simulation box when it is the opposite direction (return current). Their amplitude and the resultant luminosity of TeV photons emitted from the gap depend sensitively on the conditions; for the cases studied here the ratio of TeV luminosity to the Blandford-Znajek power ranges from 10-5 to 10-2, suggesting that strong flares may be generated by moderate changes in disk emission. We also examined the dependence of the solution on the initial number of particles per cell (PPC) and found convergence for PPC of about 50 for the cases examined. At lower PPC values the pair multiplicity is found to be artificially high, affecting the solution considerably.

Keywords: Black hole physics, Non-thermal radiation sources, Plasma astrophysics, High energy astrophysics
Pulsation-driven Mass Loss from Massive Stars behind Stellar Mergers in Metal-poor Dense Clusters. The recent discovery of high-redshift (z &gt; 6) supermassive black holes (SMBH) favors the formation of massive seed BHs in protogalaxies. One possible scenario is the formation of massive stars $\simeq {10}^{3}\mbox{--}{10}^{4}\,{M}_{\odot }$ via runaway stellar collisions in a dense cluster, leaving behind massive BHs without significant mass loss. We study the pulsational instability of massive stars with the zero-age main-sequence (ZAMS) mass ${M}_{\mathrm{ZAMS}}/{M}_{\odot }=300\mbox{--}3000$ and metallicity $Z/{Z}_{\odot }=0\mbox{--}{10}^{-1}$ , and discuss whether or not pulsation-driven mass loss prevents massive BH formation. In the MS phase, the pulsational instability excited by the ɛ-mechanism grows in $\sim {10}^{3}\,\mathrm{yr}$ . As the stellar mass and metallicity increase, the mass-loss rate increases to $\lesssim {10}^{-3}\ {M}_{\odot }\,{\mathrm{yr}}^{-1}$ . In the red supergiant (RSG) phase, the instability is excited by the κ-mechanism operating in the hydrogen ionization zone and grows more rapidly in $\sim 10\,\mathrm{yr}$ . The RSG mass-loss rate is almost independent of metallicity and distributes in the range of $\sim {10}^{-3}\mbox{--}{10}^{-2}\ {M}_{\odot }\,{\mathrm{yr}}^{-1}$ . Conducting stellar structure calculations including feedback due to pulsation-driven winds, we find that the stellar models of ${M}_{\mathrm{ZAMS}}/{M}_{\odot }=300\mbox{--}3000$ can leave behind remnant BHs more massive than $\sim 200\mbox{--}1200\ {M}_{\odot }$ . We conclude that massive merger products can seed monster SMBHs observed at z &gt; 6.

Keywords: Population II stars, Population III stars, Stellar evolution
A Late-time Radio Survey of Short Gamma-ray Bursts at z &lt; 0.5: New Constraints on the Remnants of Neutron-star Mergers. Massive, rapidly spinning magnetar remnants produced as a result of binary neutron-star (BNS) mergers may deposit a fraction of their energy into the surrounding kilonova ejecta, powering a synchrotron radio signal from the interaction of the ejecta with the circumburst medium. Here, we present 6.0 GHz Very Large Array (VLA) observations of nine, low-redshift short gamma-ray bursts (GRBs; z &lt; 0.5) on rest-frame timescales of ≈2.4-13.9 yr following the bursts. We place 3σ limits on radio continuum emission of Fν ≲ 6-20 μJy at the burst positions, or Lν ≲ (0.6-8.3) × 1028 erg s-1 Hz-1. Comparing these limits with new light-curve modeling that properly incorporates relativistic effects, we obtain limits on the energy deposited into the ejecta of Eej ≲ (0.6-6.7) × 1052 erg ( ${E}_{\mathrm{ej}}\lesssim (1.8\mbox{--}17.6)\times {10}^{52}$ erg) for an ejecta mass of 0.03 M⊙ (0.1 M⊙). We present a uniform reanalysis of 27 short GRBs with 5.5-6.0 GHz observations, and find that ≳50% of short GRBs did not form stable magnetar remnants in their mergers. Assuming short GRBs are produced by BNS mergers drawn from the Galactic BNS population plus an additional component of high-mass GW194025-like mergers in a fraction fGW190425 of cases, we place constraints on the maximum mass of a nonrotating neutron star (NS; Tolman-Oppenheimer-Volkoff mass; MTOV), finding ${M}_{{\rm{T}}{\rm{O}}{\rm{V}}}\lesssim 2.23\,{M}_{\odot }$ for fGW190425 = 0.4; this limit increases for larger values of fGW190425. The detection (or lack thereof) of radio remnants in untargeted surveys such as the VLA Sky Survey (VLASS) could provide more stringent constraints on the fraction of mergers that produce stable remnants. If $\gtrsim \,30\mbox{--}300$ radio remnants are discovered in VLASS, this suggests that short GRBs are a biased population of BNS mergers in terms of the stability of the remnants they produce.

Keywords: Neutron stars, Magnetars, Gamma-ray bursts
The Jet Structure and the Intrinsic Luminosity Function of Short Gamma-Ray Bursts. The joint observation of GW170817 and GRB 170817A indicated that short gamma-ray bursts (SGRBs) can originate from binary neutron star mergers. Moreover, some SGRBs could be detected off axis, while the SGRB jets are highly structured. Then, by assuming a universal angular distribution of the jet emission for all SGRBs, we reproduce the flux and redshift distributions of the cosmological SGRBs detected by Swift and Fermi. For self-consistency, this angular distribution is simultaneously constrained by the luminosity and event rate of GRB 170817A. As a result, it is found that the universal jet structure of SGRBs could approximately have a two-Gaussian profile. Meanwhile, the intrinsic luminosity function (LF) of the on-axis emission of the jets can be simply described by a single power law with a low-luminosity exponential cutoff. The usually discovered broken-power-law apparent LF for relatively high luminosities can naturally result from the coupling of the intrinsic LF with the angular distribution of the jet emission, as the viewing angles to the SGRBs are arbitrarily distributed.

Keywords: Gamma-ray bursts
On the Scaling Properties of Magnetic-field Fluctuations through the Inner Heliosphere. Although the interplanetary magnetic-field variability has been extensively investigated in situ using data from several space missions, newly launched missions providing high-resolution measures and approaching the Sun offer the possibility to study the multiscale variability in the innermost solar system. Here, using Parker Solar Probe measurements, we investigate the scaling properties of solar wind magnetic-field fluctuations at different heliocentric distances. The results show a clear transition at distances close to say 0.4 au. Closer to the Sun fluctuations show a f-3/2 frequency power spectra and regular scaling properties, while for distances larger than 0.4 au fluctuations show a Kolmogorov spectrum f-5/3 and are characterized by anomalous scalings. The observed statistical properties of turbulence suggest that the solar wind magnetic fluctuations, in the late stage far from the Sun, show a multifractal behavior typical of turbulence and described by intermittency, while in the early stage, when leaving the solar corona, a breakdown of these properties is observed, thus showing a statistical monofractal global self-similarity. Physically, the breakdown observed close to the Sun should be due either to a turbulence with regular statistics or to the presence of intense stochastic fluctuations able to cancel out the correlations necessary for the presence of anomalous scaling.

Keywords: Interplanetary turbulence, Solar wind, Interplanetary magnetic fields, Time series analysis