adsabs/SciX_UAT_keywords huggingface dataset:
A JWST Project on 47 Tucanae. Overview, Photometry, and Early Spectroscopic Results of M Dwarfs and Observations of Brown Dwarfs

James Webb Space Telescope (JWST) observations have been demonstrated to be efficient in detecting multiple stellar populations in globular clusters (GCs) in the low-mass regime of M dwarfs. We present an overview, and first results, of different projects that can be explored by using the JWST observations gathered under program GO2560 for 47 Tucanae, the first program entirely devoted to the investigation of multiple populations in very-low-mass stars, which includes spectroscopic data for the faintest GC stars for which spectra are available. Our color–magnitude diagram (CMD) shows some substructures for ultracool stars, including gaps and breaks in slope. In particular, we observe both a gap and a minimum in the F322W2 luminosity function less than 1 mag apart, and discuss which it could be associated with the H-burning limit. We detect stars fainter than this minimum, very likely brown dwarfs. We corroborate the ubiquity of the multiple populations across different masses, from ∼0.1 M ⊙ up to red giants (∼0.8 M ⊙). The oxygen range inferred for the M dwarfs, both from the CMD and from the spectra of two M dwarfs associated with different populations, is similar to that observed for giants. We have not detected any difference between the fractions of stars in distinct populations across stellar masses ≳ 0.1 M ⊙. This work demonstrates the JWST's capability in uncovering multiple populations within M dwarfs and illustrates the possibility to analyze very-low-mass stars in GCs approaching the H-burning limit and the brown-dwarf sequence. *The main data set presented in this article was obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute. The specific observations analyzed can be accessed via doi:10.17909/6t82-4360.

Keywords: m dwarf stars; population ii stars; ccd photometry
General Physical Properties of Gamma-Ray-emitting Radio Galaxies

We study the radio galaxies with known redshifts detected by the Fermi satellite after 10 yr of data (4FGL-DR2). We use a one-zone leptonic model to fit the quasi-simultaneous multiwavelength data of these radio galaxies and study the distributions of the derived physical parameters as a function of black hole mass and accretion disk luminosity. The main results are as follows. (1) We find that the jet kinetic power of most radio galaxies can be explained by the hybrid jet model based on ADAFs surrounding Kerr black holes. (2) After excluding the redshift, there is a significant correlation between the radiation jet power and the accretion disk luminosity, while the jet kinetic power is weakly correlated with the accretion disk luminosity. (3) We also find a significant correlation between inverse Compton luminosity and synchrotron luminosity. The slope of the correlation for radio galaxies is consistent with the synchrotron self-Compton (SSC) process. The result may suggest that the high-energy components of radio galaxies are dominated by the SSC process.

Keywords: active galactic nuclei; gamma-rays; gamma-ray sources; radio galaxies; galaxy jets
The ALMA Spectroscopic Survey in the HUDF: The Cosmic Dust and Gas Mass Densities in Galaxies up to z ∼ 3

Using the deepest 1.2 mm continuum map to date in the Hubble Ultra Deep Field, which was obtained as part of the ALMA Spectroscopic Survey (ASPECS) large program, we measure the cosmic density of dust and implied gas (H2+H I) mass in galaxies as a function of look-back time. We do so by stacking the contribution from all H-band selected galaxies above a given stellar mass in distinct redshift bins, ρdust(M* > M,z) and ρgas (M* > M,z). At all redshifts, ρdust(M* > M,z) and ρgas(M* > M,z) grow rapidly as M decreases down to 1010 M⊙, but this growth slows down toward lower stellar masses. This flattening implies that at our stellar mass-completeness limits (108 M⊙ and 108.9 M⊙ at z ∼ 0.4 and z ∼ 3), both quantities converge toward the total cosmic dust and gas mass densities in galaxies. The cosmic dust and gas mass densities increase at early cosmic time, peak around z ∼ 2, and decrease by a factor ∼4 and 7, when compared to the density of dust and molecular gas in the local universe, respectively. The contribution of quiescent galaxies (I.e., with little on-going star formation) to the cosmic dust and gas mass densities is minor (≲10%). The redshift evolution of the cosmic gas mass density resembles that of the SFR density, as previously found by CO-based measurements. This confirms that galaxies have relatively constant star formation efficiencies (within a factor ∼2) across cosmic time. Our results also imply that by z ∼ 0, a large fraction (∼90%) of dust formed in galaxies across cosmic time has either been destroyed or ejected to the intergalactic medium.

Keywords: high-redshift galaxies; galaxy evolution; galaxy formation
The Second Catalog of Interplanetary Network Localizations of Konus Short-duration Gamma-Ray Bursts

We present the catalog of InterPlanetary Network (IPN) localizations for 199 short-duration gamma-ray bursts (sGRBs) detected by the Konus-Wind (KW) experiment between 2011 January 1 and 2021 August 31, which extends the initial sample of IPN-localized KW sGRBs to 495 events. We present the most comprehensive IPN localization data on these events, including probability sky maps in Hierarchical Equal Area isoLatitude Pixelization format.

Keywords: gamma-ray bursts
HATS-71b: A Giant Planet Transiting an M3 Dwarf Star in TESS Sector 1

We report the discovery of HATS-71b, a transiting gas giant planet on a $P=3.7955$ day orbit around a $G=15.35$ mag M3 dwarf star. HATS-71 is the coolest M dwarf star known to host a hot Jupiter. The loss of light during transits is 4.7%, more than in any other confirmed transiting planet system. The planet was identified as a candidate by the ground-based HATSouth transit survey. It was confirmed using ground-based photometry, spectroscopy, and imaging, as well as space-based photometry from the NASA Transiting Exoplanet Survey Satellite mission (TIC 234523599). Combining all of these data, and utilizing Gaia DR2, we find that the planet has a radius of $1.024\pm 0.018$ ${R}_{{\rm{J}}}$ and mass of $0.37\,\pm 0.24$ ${M}_{{\rm{J}}}$ (95% confidence upper limit of $\lt 0.80$ ${M}_{{\rm{J}}}$ ), while the star has a mass of $0.4861\pm 0.0060$ ${M}_{\odot }$ and a radius of $0.4783\pm 0.0060$ ${R}_{\odot }$ .

Keywords: exoplanets; exoplanet detection methods; transit photometry; radial velocity; astronomical instrumentation; observational astronomy
The Lick AGN Monitoring Project 2016: Dynamical Modeling of Velocity-resolved Hβ Lags in Luminous Seyfert Galaxies

We have modeled the velocity-resolved reverberation response of the Hβ broad emission line in nine Seyfert 1 galaxies from the Lick Active Galactic Nucleus (AGN) Monitoring Project 2016 sample, drawing inferences on the geometry and structure of the low-ionization broad-line region (BLR) and the mass of the central supermassive black hole. Overall, we find that the Hβ BLR is generally a thick disk viewed at low to moderate inclination angles. We combine our sample with prior studies and investigate line-profile shape dependence, such as ${\mathrm{log}}_{10}(\mathrm{FWHM}/\sigma )$ , on BLR structure and kinematics and search for any BLR luminosity-dependent trends. We find marginal evidence for an anticorrelation between the profile shape of the broad Hβ emission line and the Eddington ratio, when using the rms spectrum. However, we do not find any luminosity-dependent trends, and conclude that AGNs have diverse BLR structure and kinematics, consistent with the hypothesis of transient AGN/BLR conditions rather than systematic trends.

Keywords: active galaxies; active galactic nuclei; seyfert galaxies
Cluster Analysis of Presolar Silicon Carbide Grains: Evaluation of Their Classification and Astrophysical Implications

Cluster analysis of presolar silicon carbide grains based on literature data for 12C/13C, 14N/15N, δ30Si/28Si, and δ29Si/28Si including or not inferred initial 26Al/27Al data, reveals nine clusters agreeing with previously defined grain types but also highlighting new divisions. Mainstream grains reside in three clusters probably representing different parent star metallicities. One of these clusters has a compact core, with a narrow range of composition, pointing to an enhanced production of SiC grains in asymptotic giant branch (AGB) stars with a narrow range of masses and metallicities. The addition of 26Al/27Al data highlights a cluster of mainstream grains, enriched in 15N and 26Al, which cannot be explained by current AGB models. We defined two AB grain clusters, one with 15N and 26Al excesses, and the other with 14N and smaller 26Al excesses, in agreement with recent studies. Their definition does not use the solar N isotopic ratio as a divider, and the contour of the 26Al-rich AB cluster identified in this study is in better agreement with core-collapse supernova models. We also found a cluster with a mixture of putative nova and AB grains, which may have formed in supernova or nova environments. X grains make up two clusters, having either strongly correlated Si isotopic ratios or deviating from the 2/3 slope line in the Si 3-isotope plot. Finally, most Y and Z grains are jointly clustered, suggesting that the previous use of 12C/13C = 100 as a divider for Y grains was arbitrary. Our results show that cluster analysis is a powerful tool to interpret the data in light of stellar evolution and nucleosynthesis modeling and highlight the need of more multi-element isotopic data for better classification.

Keywords: nucleosynthesis; interstellar dust; clustering; stellar evolution
L-dwarf Detection from SDSS Images using Improved Faster R-CNN

We present a data-driven approach to automatically detect L dwarfs from Sloan Digital Sky Survey (SDSS) images using an improved Faster R-CNN framework based on deep learning. The established L-dwarf automatic detection (LDAD) model distinguishes L dwarfs from other celestial objects and backgrounds in SDSS field images by learning the features of 387 SDSS images containing L dwarfs. Applying the LDAD model to the SDSS images containing 93 labeled L dwarfs in the test set, we successfully detected 83 known L dwarfs with a recall rate of 89.25% for known L dwarfs. Several techniques are implemented in the LDAD model to improve its detection performance for L dwarfs, including the deep residual network and the feature pyramid network. As a result, the LDAD model outperforms the model of the original Faster R-CNN, whose recall rate of known L dwarfs is 80.65% for the same test set. The LDAD model was applied to detect L dwarfs from a larger validation set including 843 labeled L dwarfs, resulting in a recall rate of 94.42% for known L dwarfs. The newly identified candidates include L dwarfs, late M and T dwarfs, which were estimated from color (i - z) and spectral type relation. The contamination rates for the test candidates and validation candidates are 8.60% and 9.27%, respectively. The detection results indicate that our model is effective to search for L dwarfs from astronomical images.

Keywords: astronomy data analysis; l dwarfs
Astrometric and Photometric Investigation of Three Old Age Open Clusters in the Gaia Era: Berkeley 32, Berkeley 98, and King 23

Using the photometric and kinematical data from Gaia Data Release 2, three old open clusters namely Berkeley 32 (Be 32), Berkeley 98 (Be 98), and King 23 are investigated. The latter two of these clusters are poorly studied in the literature. The numbers of the most probable cluster members are 563, 260, and 114 for Be 32, Be 98, and King 23, respectively, with membership probabilities higher than 80% and lying within the clusters' limiting radii. Mean proper motions (PMs; ${\mu }_{\alpha }\cos \delta $ and μδ) of the clusters are determined as (-0.34 ± 0.008, -1.60 ± 0.006), (-1.34 ± 0.007, -3.22 ± 0.008), and (-0.46 ± 0.009, -0.87 ± 0.012) mas yr-1. The errors mentioned in the PMs are the Gaussian fitting errors. The blue straggler stars (BSS) in all three old clusters were found to exhibit centralized radial distribution. The clusters' radii are determined as 9'4, 12'95, and 6'6 for Be 32, Be 98, and King 23 using radial density profiles. Ages of the clusters determined by isochrone fitting are 4.90 ± 0.22, 3.23 ± 0.15, and 1.95 ± 0.22 Gyr. The errors given in the clusters' ages are the internal errors. The mass function slopes are found to be flatter than Salpeter's value for all three clusters. All three clusters are found to be dynamically relaxed. Galactic orbits are derived for these clusters, which demonstrate that the studied clusters follow a circular path around the Galactic center.

Keywords: hertzsprung russell diagram; star clusters; open star clusters; initial mass function; orbit determination
The 14 Her Planetary System: Companion Masses and Architecture from Radial Velocities and Astrometry

We combine Hubble Space Telescope (HST) Fine Guidance Sensor, Hipparcos, and Gaia DR3 astrometric observations of the K0 V star 14 Her with the results of an analysis of extensive ground-based radial velocity data to determine perturbation orbits and masses for two previously known companions, 14 Her b and c. Radial velocities obtained with the Hobby-Eberly Telescope and from the literature now span over 25 years. With these data we obtain improved radial velocity (RV) orbital elements for both the inner companion, 14 Her b and the long-period outer companion, 14 Her c. We also find evidence of an additional RV signal with P ~ 3789d. We then model astrometry from Hipparcos, HST, and Gaia with RV results to obtain system parallax and proper motion, perturbation periods, inclinations, and sizes due to 14 Her b and c. We find P b = 1767.6 ± 0.2 days, perturbation semimajor axis α b = 1.3 ± 0.1 mas, and inclination i b = 36° ± 3°, P c = 52160 ± 1028 days, perturbation semimajor axis α c = 10.3 ± 0.7 mas, and inclination i c = 82° ± 14°. In agreement with a past investigation, the 14 Her b, c orbits exhibit significant mutual inclination. Assuming a primary mass M * = 0.98 ± 0.04M ⊙, we obtain companion masses ${{ \mathcal M }}_{{\rm{b}}}={8.5}_{-0.8}^{+1.0}$ ${{ \mathcal M }}_{\mathrm{Jup}}\,$ and ${{ \mathcal M }}_{{\rm{c}}}={7.1}_{-0.6}^{+1.0}$ ${{ \mathcal M }}_{\mathrm{Jup}}$ .

Keywords: exoplanets
ALMA CO Observations of the Mixed-morphology Supernova Remnant W49B: Efficient Production of Recombining Plasma and Hadronic Gamma Rays via Shock-Cloud Interactions

We carried out new CO(J = 2-1) observations toward the mixed-morphology supernova remnant (SNR) W49B with the Atacama Large Millimeter/submillimeter Array. We found that CO clouds at ~10 km s-1 show a good spatial correspondence to the synchrotron radio continuum as well as to an X-ray deformed shell. The bulk mass of molecular clouds accounts for the western part of the shell, not the eastern shell, where near-infrared H2 emission is detected. The molecular clouds at ~10 km s-1 show higher kinetic temperatures of ~20-60 K, suggesting that modest shock heating occurred. The expanding motion of the clouds with ΔV ~ 6 km s-1 was formed by strong winds from the progenitor system. We argue that the barrel-like structure of Fe-rich ejecta was possibly formed not only by an asymmetric explosion, but also by interactions with dense molecular clouds. We also found a negative correlation between the CO intensity and the electron temperature of recombining plasma, implying that the origin of the high-temperature recombining plasma in W49B can be understood to be the thermal conduction model. The total energy of accelerated cosmic-ray protons Wp is estimated to be ~2 × 1049 erg by adopting an averaged gas density of ~650 ± 200 cm-3. The SNR age-Wp diagram indicates that W49B shows one of the highest in situ values of Wp among gamma-ray-bright SNRs.

Keywords: supernova remnants; interstellar medium; cosmic ray sources; gamma-ray sources; x-ray sources
Modeling Interactions of Narrowband Large Amplitude Whistler-mode Waves with Electrons in the Solar Wind inside 0.3 au and at 1 au Using a Particle Tracing Code

The discovery of large amplitude narrowband whistler-mode waves at frequencies oftenths of the electron cyclotron frequency in large numbers both inside 0.3 au and at 1 au provides an answer to longstanding questions about scattering and energization of solar wind electrons. The waves can have rapid nonlinear interactions with electrons over a broad energy range. Counter propagation between electrons and waves is not required for resonance with the obliquely propagating waves in contrast to the case for parallel propagation. Using a full 3D particle tracing code, we have examined interactions of electrons with energies from 0 eV to 2 keV with whistler-mode waves with amplitudes of 20 mV m1 andpropagation angles from 0 to 180 to the background magnetic field. Interactions with wave packets and single waves are both modeled based on observations at 0.3 au and 1 au. A test particle simulation approach allows us to examine the particle motion in detail, which reveals kinetic effects of resonant interactions. The simulations demonstrate the key role played by these waves in rapid scattering and energization of electrons. Strong scattering and energization for some initial energy and pitch angle ranges occurs for both counter-propagating and obliquely propagating waves. Strong scattering of strahl electrons counteracts the pitch angle narrowing due to conservation of the first adiabatic invariant as electrons propagate from the Sun into regions of smaller magnetic field. Scattering also produces the hotter isotropic halo. The concomitant limiting of the electron heat flux is also relevant in other astrophysical settings.

Keywords: plasma physics; plasma astrophysics; solar physics
Magnetic Field Intermittency in the Solar Wind: Parker Solar Probe and SolO Observations Ranging from the Alfvén Region up to 1 AU

Parker Solar Probe (PSP) and SolO data are utilized to investigate magnetic field intermittency in the solar wind (SW). Small-scale intermittency (20-100 d i ) is observed to radially strengthen when methods relying on higher-order moments are considered (SF q ; SDK), but no clear trend is observed at larger scales. However, lower-order moment-based methods (e.g., partial variance of increments; PVI) are deemed more appropriate for examining the evolution of the bulk of coherent structures (CSs), PVI ≥ 3. Using PVI, we observe a scale-dependent evolution in the fraction of the data set occupied by CSs, f PVI≥3. Specifically, regardless of the SW speed, a subtle increase is found in f PVI≥3 for ℓ = 20 d i , in contrast to a more pronounced radial increase in CSs observed at larger scales. Intermittency is investigated in relation to plasma parameters. Though, slower SW speed intervals exhibit higher f PVI≥6 and higher kurtosis maxima, no statistical differences are observed for f PVI≥3. Highly Alfvénic intervals display lower levels of intermittency. The anisotropy with respect to the angle between the magnetic field and SW flow, ΘVB is investigated. Intermittency is weaker at ΘVB ≈ 0° and is strengthened at larger angles. Considering the evolution at a constant alignment angle, a weakening of intermittency is observed with increasing advection time of the SW. Our results indicate that the strengthening of intermittency in the inner heliosphere is driven by the increase in comparatively highly intermittent perpendicular intervals sampled by the probes with increasing distance, an effect related directly to the evolution of the Parker spiral.

Keywords: solar wind; interplanetary turbulence; magnetohydrodynamics; space plasmas; plasma astrophysics; solar physics
The Fast Radio Burst Luminosity Function and Death Line in the Low-twist Magnetar Model

We explore the burst energy distribution of fast radio bursts (FRBs) in the low-twist magnetar model of Wadiasingh & Timokhin (WT19). Motivated by the power-law fluence distributions of FRB 121102, we propose an elementary model for the FRB luminosity function of individual repeaters with an inversion protocol that directly relates the power-law distribution index of magnetar short burst fluences to that for FRBs. The protocol indicates that the FRB energy scales virtually linearly with crust/field dislocation amplitude, if magnetar short bursts prevail in the magnetoelastic regime. Charge starvation in the magnetosphere during bursts (required in WT19) for individual repeaters implies the predicted burst fluence distribution is narrow, &lsim;3 decades for yielding strains and oscillation frequencies feasible in magnetar crusts. Requiring magnetic confinement and charge starvation, we obtain a death line for FRBs, which segregates magnetars from the normal pulsar population, suggesting only the former will host recurrent FRBs. We convolve the burst energy distribution for individual magnetars to define the distribution of luminosities in evolved magnetar populations. The broken power-law luminosity function's low-energy character depends on the population model, while the high-energy index traces that of individual repeaters. Independent of the evolved population, the broken power-law isotropic-equivalent energy/luminosity function peaks at ∼1037-1040 erg with a low-energy cutoff at ∼1037 erg. Lastly, we consider the local fluence distribution of FRBs and find that it can constrain the subset of FRB-producing magnetar progenitors. Our model suggests that improvements in sensitivity may reveal a flattening of the global FRB fluence distribution and saturation in FRB rates.

Keywords: magnetars; neutron stars; radio transient sources; radio bursts; x-ray bursts; gamma-ray bursts; optical bursts; non-thermal radiation sources; x-ray transient sources; high energy astrophysics; luminosity function; cosmology
Tidal Disruption Events through the Lens of the Cooling Envelope Model

The cooling envelope model for tidal disruption events (TDEs) postulates that while the stellar debris streams rapidly dissipate their bulk kinetic energy ("circularize"), this does not necessarily imply rapid feeding of the supermassive black hole (SMBH). The bound material instead forms a large pressure-supported envelope that powers optical/UV emission as it undergoes gradual Kelvin-Helmholtz contraction. We present results interpreting a sample of 15 optical TDEs within the cooling envelope model in order to constrain the SMBH mass M BH, stellar mass M ⋆, and orbital penetration factor β. The distributions of inferred properties from our sample broadly follow the theoretical expectations of loss-cone analysis assuming a standard stellar initial mass function. However, we find a deficit of events with M BH ≲ 5 × 105 and M ⋆ ≲ 0.5 M ⊙, which could result in part from the reduced detectability of TDEs with these properties. Our model fits also illustrate the predicted long delay between the optical light-curve peak and when the SMBH accretion rate reaches its maximum. The latter occurs only once the envelope contracts to the circularization radius on a timescale of months to years, consistent with delayed-rising X-ray and nonthermal radio flares seen in a growing number of TDEs.

Keywords: tidal disruption; supermassive black holes