Sazuna/UAT_keywords huggingface dataset:
Evidence of Core Growth in the Dragon Infrared Dark Cloud: A Path for Massive Star Formation. A sample of 1.3 mm continuum cores in the Dragon infrared dark cloud (also known as G28.37+0.07 or G28.34+0.06) is analyzed statistically. Based on their association with molecular outflows, the sample is divided into protostellar and starless cores. Statistical tests suggest that the protostellar cores are more massive than the starless cores, even after temperature and opacity biases are accounted for. We suggest that the mass difference indicates core mass growth since their formation. The mass growth implies that massive star formation may not have to start with massive prestellar cores, depending on the core mass growth rate. Its impact on the relation between core mass function and stellar initial mass function is to be further explored.

Keywords: Observational astronomy, Interstellar filaments, Nonparametric hypothesis tests, Infrared dark clouds, Millimeter astronomy, Stellar jets, Young massive clusters, Massive stars, Young stellar objects, Star formation, Protostars, Astrostatistics strategies
Extreme r-process Enhanced Stars at High Metallicity in Fornax. We present and discuss three extremely r-process enhanced stars located in the massive dwarf spheroidal galaxy Fornax. These stars are very unique with an extreme Eu enrichment (1.25 ≤ [Eu/Fe]≤1.45) at high metallicities (-1.3 ≤ [Fe/H]≤-0.8). They have the largest Eu abundances ever observed in a dwarf galaxy opening new opportunities to further understand the origin of heavy elements formed by the r-process. We derive stellar abundances of Co, Zr, La, Ce, Pr, Nd, Er, and Lu using one-dimensional, local thermodynamic equilibrium codes and model atmospheres in conjunction with state-of-the art yield predictions. We derive Zr in the largest sample of stars (105) known to date in a dwarf galaxy. Accurate stellar abundances combined with a careful assessment of the yield predictions have revealed three metal-rich stars in Fornax showing a pure r-process pattern. We define a new class of stars, namely, Eu-stars, as r-II stars (i.e., [Eu/Fe] &gt; 1) at high metallicities (i.e., [Fe/H] ≳ -1.5). The stellar abundance pattern contains Lu, observed for the first time in a dwarf galaxy, and reveals that a late burst of star formation has facilitated extreme r-process enhancement late in the galaxy's history (&lt;4 Gyr ago). Due to the large uncertainties associated with the nuclear physics input in the yield predictions, we cannot yet determine the r-process site leading to the three Eu-stars in Fornax. Our results demonstrate that extremely r-rich stars are not only associated with ultra-faint low-mass dwarf galaxies, but can be born also in massive dwarf galaxies. * Based on data obtained from the ESO reduced archive. Program IDs: 080.B-0784(A), 171.B-0588(A), 71.B-0641(A).

Keywords: Chemically peculiar stars, Nucleosynthesis, R-process, Chemical abundances, Dwarf spheroidal galaxies, Fornax dwarf spheroidal galaxy
Constraining the Origin of the Puzzling Source HESS J1640-465 and the PeVatron Candidate HESS J1641-463 Using Fermi-Large Area Telescope Observations. There are only a few very-high-energy sources in our Galaxy that might accelerate particles up to the knee of the cosmic-ray spectrum. To understand the mechanisms of particle acceleration in these PeVatron candidates, Fermi-Large Area Telescope (LAT) and High-Energy Stereoscopic System (H.E.S.S.) observations are essential to characterize their γ-ray emission. HESS J1640-465 and the PeVatron candidate HESS J1641-463 are two neighboring (0.25°) γ-ray sources, spatially coincident with the radio supernova remnants (SNRs) G338.3-0.0 and G338.5+0.1. Detected both by H.E.S.S. and the Fermi-LAT, we present here a morphological and spectral analysis of these two sources using 8 yr of Fermi-LAT data between 200 MeV and 1 TeV with multiwavelength observations to assess their nature. The morphology of HESS J1640-465 is described by a 2D Gaussian (σ = 0.053° ± 0.011°stat ± 0.03°syst) and its spectrum is modeled by a power law with a spectral index Γ = 1.8 ± 0.1stat ± 0.2syst. HESS J1641-463 is detected as a point-like source and its GeV emission is described by a logarithmic-parabola spectrum with α = 2.7 ± 0.1stat ± 0.2syst and significant curvature of β = 0.11 ± 0.03stat ± 0.05syst. Radio and X-ray flux upper limits were derived. We investigated scenarios to explain their emission, namely, the emission from accelerated particles within the SNRs spatially coincident with each source, molecular clouds illuminated by cosmic rays from the close-by SNRs, and a pulsar/pulsar wind nebula origin. Our new Fermi-LAT results and the radio and flux X-ray upper limits pose severe constraints on some of these models.

Keywords: Supernova remnants, Gamma-ray astronomy, Cosmic rays, Pulsars
Does the Magnetic Field Suppress Fragmentation in Massive Dense Cores?. Theoretical and numerical works indicate that a strong magnetic field should suppress fragmentation in dense cores. However, this has never been tested observationally in a relatively large sample of fragmenting massive dense cores. Here, we use the polarization data obtained in the Submillimeter Array Legacy Survey of Zhang et al. to build a sample of 18 massive dense cores where both fragmentation and magnetic field properties are studied in a uniform way. We measured the fragmentation level, Nmm, within the field of view common to all regions of ∼0.15 pc, with a mass sensitivity of ∼0.5 M⊙, and a spatial resolution of ∼1000 au. In order to obtain the magnetic field strength using the Davis-Chandrasekhar-Fermi method, we estimated the dispersion of the polarization position angles, the velocity dispersion of the H13CO+(4-3) gas, and the density of each core, all averaged within 0.15 pc. A strong correlation is found between Nmm and the average density of the parental core, although with significant scatter. When large-scale systematic motions are separated from the velocity dispersion and only the small-scale (turbulent) contribution is taken into account, a tentative correlation is found between Nmm and the mass-to-flux ratio, as suggested by numerical and theoretical works.

Keywords: Star formation, Interstellar magnetic fields, Young star clusters
Tully-Fisher Distances and Dynamical Mass Constraints for 24 Host Galaxies of Reverberation-mapped AGNs. We present Tully-Fisher distances for 24 active galactic nucleus (AGN) host galaxies with black hole mass (MBH) measurements from reverberation mapping, as well as the first calibration of the V-band Tully-Fisher relation. Combining our measurements of H I 21 cm emission with Hubble Space Telescope and ground-based optical and near-infrared images allows multiple distance measurements for 19 galaxies and single measurements for the remaining 5. Separation of the nucleus from its host galaxy via surface brightness decomposition yields galaxy-only luminosities, thus allowing measurements of the distance moduli free of contamination from the AGNs. For 14 AGN hosts, these are the first reported distances independent of redshift, and hence independent of peculiar velocities. For the remaining galaxies, we show good agreement between our distances and those previously reported from surface brightness fluctuations and Cepheids. We also determine the total galaxy mass enclosed within the estimated H I radius, which when compared to the baryonic content allows for constraints on the dark matter masses. We find a typical mass fraction of MDM/MDYN = 62%, and find significant correlations between MBH-MDYN and MBH-MDM. Finally, we scale our galaxy radii based on estimated relationships between visible and halo radii and assume a flat rotation curve out to the halo radius to approximate MHALO. Over the range of MBH and MHALO in this sample, we find good agreement with observationally constrained relationships between MBH and MHALO and with hydrodynamical simulations.

Keywords: AGN host galaxies, Galaxy masses, Galaxy distances, Seyfert galaxies
A Complete 16 μm Selected Galaxy Sample at z ∼ 1: Mid-infrared Spectral Energy Distributions. We describe a complete, flux-density-limited sample of galaxies at redshift 0.8 &lt; z &lt; 1.3 selected at 16 μm. At the selection wavelength near 8 μm rest, the observed emission comes from both dust heated by intense star formation and active galactic nuclei (AGNs). Fitting the spectral energy distributions (SEDs) of the sample galaxies to local-galaxy templates reveals that more than half the galaxies have SEDs dominated by star formation. About one-sixth of the galaxy SEDs are dominated by an AGN, and nearly all of the rest of the SEDs are composite. Comparison with X-ray and far-infrared observations shows that combinations of luminosities at rest-frame 4.5 and 8 μm give good measures of both AGN luminosity and star formation rate. The sample galaxies mostly follow the established star-forming main sequence for z = 1 galaxies, but of the galaxies more than 0.5 dex above that main sequence, more than half have AGN-type SEDs. Similarly, the most luminous AGNs tend to have higher star formation rates than the main-sequence value. Galaxies with stellar masses &gt;1011 M⊙ are unlikely to host an AGN. About 1% of the sample galaxies show an SED with dust emission typical of neither star formation nor an AGN.

Keywords: Spectral energy distribution, Sky surveys, Infrared galaxies, Luminous infrared galaxies
3D Morphology of Open Clusters in the Solar Neighborhood with Gaia EDR 3: Its Relation to Cluster Dynamics. We analyze the 3D morphology and kinematics of 13 open clusters (OCs) located within 500 pc of the Sun, using Gaia EDR 3 and kinematic data from the literature. Members of OCs are identified using the unsupervised machine-learning method StarGO, using five parameters (X, Y, Z, ${\mu }_{\alpha }\cos \delta ,{\mu }_{\delta }$ ). The OC sample covers an age range of 25 Myr to 2.65 Gyr. We correct the asymmetric distance distribution that is due to parallax error using Bayesian inversion. The uncertainty in the corrected distance for a cluster at 500 pc is 3.0-6.3 pc, depending on the intrinsic spatial distribution of its members. We determine the 3D morphology of the OCs in our sample and fit the spatial distribution of stars within the tidal radius in each cluster with an ellipsoid model. The shapes of the OCs are well described with oblate spheroids (NGC 2547, NGC 2516, NGC 2451A, NGC 2451B, and NGC 2232), prolate spheroids (IC 2602, IC 4665, NGC 2422, Blanco 1, and Coma Berenices), or triaxial ellipsoids (IC 2391, NGC 6633, and NGC 6774). The semimajor axis of the fitted ellipsoid is parallel to the Galactic plane for most clusters. Elongated filament-like substructures are detected in three young clusters (NGC 2232, NGC 2547, and NGC 2451B), while tidal-tail-like substructures (tidal tails) are found in older clusters (NGC 2516, NGC 6633, NGC 6774, Blanco 1, and Coma Berenices). Most clusters may be supervirial and expanding. N-body models of rapid gas expulsion with a star formation efficiency of ≈1/3 are consistent with clusters more massive than 250 M⊙, while clusters less massive than 250 M⊙ tend to agree with adiabatic gas expulsion models. Only five OCs (NGC 2422, NGC 6633, NGC 6774, Blanco 1, and Coma Berenices) show clear signs of mass segregation.

Keywords: Open star clusters, Stellar dynamics, Star clusters
Constraints on Chondrule Generation, Disk Dynamics, and Asteroid Accretion from the Compositions of Carbonaceous Meteorites. The elemental and isotopic compositions of meteorites are expected to reflect several key processes that occurred in the early solar system, including the migration of gas and dust throughout the protoplanetary disk, the formation of chondrules, and the accretion of the first planetary bodies. However, the specific origins of the various compositions measured among these rocks are currently poorly constrained, limiting our understanding of these processes. Here, we use previously measured elemental and isotopic compositions of chondrites and iron meteorites to identify that carbonaceous (CC) meteorites are mixtures of noncarbonaceous (NC) material, calcium-aluminum-rich inclusion (CAI) material, and CI (Ivuna-like) material, in varying proportions. These trends indicate that chondrules in CO (Ornans-like), CM (Mighei-like), CV (Vigarano-like), and TL (Tagish Lake) chondrites share near-identical average proportions of CI material, arguing that they were generated through the remelting of preexisting NC chondrules all in the same disk environment. Because this proportion likely evolved over space and time throughout the disk, this similarity argues that these chondrules originate from a restricted spatial region and time interval, favoring their generation through a localized event. Moreover, the compositions of CR (Renazzo-like) chondrites indicate that their constituents formed through mechanisms different from those in CO, CM, CV, and TL chondrites. The recovered proportions of CI material in CC iron meteorites and chondrites together also argue for evolution in either the predominant direction of dust and gas motion in the first ∼10 au of the disk or the radial distance of planetesimal accretion throughout the CC reservoir.

Keywords: Isotopic abundances, Meteorite composition, Asteroids, Carbonaceous chondrites, Chondrules, Iron meteorites, Protoplanetary disks, Planetesimals, Meteorites
Estimate on Dust Scale Height from the ALMA Dust Continuum Image of the HD 163296 Protoplanetary Disk. We aim at estimating the dust scale height of protoplanetary disks from millimeter continuum observations. First, we present a general expression of intensity of a ring in a protoplanetary disk and show that we can constrain the dust scale height by the azimuthal intensity variation. Then, we apply the presented methodology to the two distinct rings at 68 au and at 100 au of the protoplanetary disk around HD 163296. We constrain the dust scale height by comparing the high-resolution millimeter dust continuum image obtained in the Disk Substructures at High Angular Resolution Project (DSHARP) with radiative transfer simulations using RADMC-3D. We find that hd/hg &gt; 0.84 at the inner ring and hd/hg &lt; 0.11 at the outer ring with 3σ uncertainties, where hd is the dust scale height and hg is the gas scale height. This indicates that the dust is flared at the inner ring and settled at the outer ring. We further constrain the ratio of the turbulence parameter α to the gas-to-dust-coupling parameter St from the derived dust scale height; α/St &gt; 2.4 at the inner ring, and α/St &lt; $1.1\times {10}^{-2}$ at the outer ring. This result shows that the turbulence is stronger or the dust is smaller at the inner ring than at the outer ring.

Keywords: Radiative transfer simulations, Dust continuum emission, Protoplanetary disks, Submillimeter astronomy, Planet formation
Massive White Dwarfs in Young Star Clusters. We have carried out a search for massive white dwarfs (WDs) in the direction of young open star clusters using the Gaia DR2 database. The aim of this survey was (1) to provide robust data for new and previously known high-mass WDs regarding cluster membership, (2) to highlight WDs previously included in the initial final mass relation (IFMR) that are unlikely members of their respective clusters according to Gaia astrometry, and (3) to select an unequivocal WD sample that could then be compared with the host clusters' turnoff masses. All promising WD candidates in each cluster color-magnitude diagram were followed up with spectroscopy from Gemini in order to determine whether they were indeed WDs and derive their masses, temperatures, and ages. In order to be considered cluster members, white dwarfs were required to (1) have proper motions and parallaxes within 2σ, 3σ, or 4σ of those of their potential parent cluster based on how contaminated the field was in their region of the sky, (2) have a cooling age that was less than the cluster age, and (3) have a mass that was broadly consistent with the IFMR. A number of WDs included in current versions of the IFMR turned out to be nonmembers, and a number of apparent members, based on Gaia's astrometric data alone, were rejected, as their mass and/or cooling times were incompatible with cluster membership. In this way, we developed a highly selected IFMR sample for high-mass WDs that, surprisingly, contained no precursor masses significantly in excess of ∼ 6 M☉.

Keywords: White dwarf stars, Young star clusters, Chandrasekhar limit, Compact objects, Open star clusters, Supernovae
High H<SUB>0</SUB> Values from CMB E-mode Data: A Clue for Resolving the Hubble Tension?. The E-mode (EE) CMB power spectra measured by Planck, ACTPol, and SPTpol constrain the Hubble constant to be 70.0 ± 2.7, ${72.4}_{-4.8}^{+3.9}$ , and ${73.1}_{-3.9}^{+3.3}$ km s-1 Mpc-1 within the standard ΛCDM model (posterior mean and central 68% interval bounds). These values are higher than the constraints from the Planck temperature (TT) power spectrum, and consistent with the Cepheid-supernova distance ladder measurement H0 = 73.2 ± 1.3 km s-1 Mpc-1. If this preference for a higher value was strengthened in a joint analysis it could provide an intriguing hint at the resolution of the Hubble disagreement. We show, however, that combining the Planck, ACTPol, and SPTpol EE likelihoods yields H0 = 68.7 ± 1.3 km s-1 Mpc-1, 2.4σ lower than the distance ladder measurement. This is due to different degeneracy directions across the full parameter space, particularly involving the baryon density, Ωbh2, and scalar tilt, ns, arising from sensitivity to different multipole ranges. We show that the E-mode ΛCDM constraints are consistent across the different experiments within 1.4σ, and with the Planck TT results at 0.8σ. Combining the Planck, ACTPol, and SPTpol EE data constrains the phenomenological lensing amplitude, AL = 0.89 ± 0.10, consistent with the expected value of unity.

Keywords: Hubble constant, Observational cosmology, Cosmic microwave background radiation
Relics of Supermassive Black Hole Seeds: The Discovery of an Accreting Black Hole in an Optically Normal, Low Metallicity Dwarf Galaxy. The detection and characterization of supermassive black holes (SMBHs) in local low mass galaxies is crucial to our understanding of the origins of SMBHs. This statement assumes that low mass galaxies have had a relatively quiet cosmic history, so that their black holes have not undergone significant growth and therefore can be treated as relics of the original SMBH seeds. While recent studies have found optical signatures of active galactic nuclei (AGNs) in a growing population of dwarf galaxies, these studies are biased against low metallicity and relatively merger-free galaxies, thus missing precisely the demographic in which to search for the relics of SMBH seeds. Here, we report the detection of the [Si VI]1.963 μm coronal line (CL), a robust indicator of an AGN in the galaxy SDSS J160135.95+311353.7, a nearby (z = 0.031) low metallicity galaxy with a stellar mass approximately an order of magnitude lower than the LMC (M* ≍ 108.56 M☉) and no optical evidence for an AGN. The AGN bolometric luminosity implied by the CL detection is ≍1042 erg s-1, precisely what is predicted from its near-infrared continuum emission based on well-studied AGNs. Our results are consistent with a black hole of mass ≍105 M☉, in line with expectations based on its stellar mass. This is the first time a near-infrared CL has been detected in a low mass, low metallicity galaxy with no optical evidence for AGN activity, providing confirmation of the utility of infrared CLs in finding AGNs in low mass galaxies when optical diagnostics fail. These observations highlight a powerful avenue of investigation to hunt for low mass black holes in the James Webb Space Telescope era.

Keywords: Dwarf galaxies, Active galactic nuclei
Narrowing the Mass Range of Fuzzy Dark Matter with Ultrafaint Dwarfs. Fuzzy dark matter (FDM) is an attractive dark matter candidate motivated by small-scale problems in astrophysics and with a rich phenomenology on those scales. We scrutinize the FDM model, more specifically the mass of the FDM particle, through a dynamical analysis for the Galactic ultrafaint dwarf (UFD) galaxies. We use a sample of 18 UFDs to place the strongest constraints to date on the mass of the FDM particle, updating on previous bounds using a subset of the sample used here. We find that most of the sample UFDs prefer an FDM particle mass heavier than 10-21 eV. In particular, Segue 1 provides the strongest constraint, with ${m}_{\psi }={1.1}_{-0.7}^{+8.3}\times {10}^{-19}\,\mathrm{eV}$ . The constraints found here are the first that are compatible with various other independent cosmological and astrophysical bounds found in the literature, in particular with the latest bounds using the Lyα forest. We also find that the constraints obtained in this work are not compatible with the bounds from luminous dwarf galaxies, as already pointed out in the previous work using UFDs. This could indicate that although a viable dark matter model, it might be challenging for the FDM model to solve the small-scale problems.

Keywords: Galaxy dynamics, Dark matter, Dwarf spheroidal galaxies
HAWC Search for High-mass Microquasars. Microquasars with high-mass companion stars are promising very high energy (VHE; 0.1-100 TeV) gamma-ray emitters, but their behaviors above 10 TeV are poorly known. Using the High Altitude Water Cerenkov (HAWC) observatory, we search for excess gamma-ray emission coincident with the positions of known high-mass microquasars (HMMQs). No significant emission is observed for LS 5039, Cyg X-1, Cyg X-3, and SS 433 with 1523 days of HAWC data. We set the most stringent limit above 10 TeV obtained to date on each individual source. Under the assumption that HMMQs produce gamma rays via a common mechanism, we have performed source-stacking searches, considering two different scenarios: (I) gamma-ray luminosity is a fraction ϵγ of the microquasar jet luminosity, and (II) VHE gamma rays are produced by relativistic electrons upscattering the radiation field of the companion star in a magnetic field B. We obtain ϵγ &lt; 5.4 × 10-6 for scenario I, which tightly constrains models that suggest observable high-energy neutrino emission by HMMQs. In the case of scenario II, the nondetection of VHE gamma rays yields a strong magnetic field, which challenges synchrotron radiation as the dominant mechanism of the microquasar emission between 10 keV and 10 MeV.

Keywords: Gamma-ray sources, High mass x-ray binary stars
The First Radio Spectrum of a Rapidly Rotating A-type Star. The radio spectra of main-sequence stars remain largely unconstrained due to the lack of observational data to inform stellar atmosphere models. As such, the dominant emission mechanisms at long wavelengths, how they vary with spectral type, and how much they contribute to the expected brightness at a given radio wavelength are still relatively unknown for most spectral types. We present radio continuum observations of Altair, a rapidly rotating A-type star. We observed Altair with NOEMA in 2018 and 2019 at 1.34, 2.09, and 3.22 mm and with the Very Large Array in 2019 at 6.7 and 9.1 mm. In the radio spectra, we see a brightness temperature minimum at millimeter wavelengths followed by a steep rise to temperatures larger than the optical photosphere, behavior that is unexpected for A-type stars. We use these data to produce the first submillimeter to centimeter spectrum of a rapidly rotating A-type star informed by observations. We generated both PHOENIX and KINICH-PAKAL model atmospheres and determine the KINICH-PAKAL model better reproduces Altair's radio spectrum. The synthetic spectrum shows a millimeter brightness temperature minimum followed by significant emission over that of the photosphere at centimeter wavelengths. Together, these data and models show how the radio spectrum of an A-type star can reveal the presence of a chromosphere, likely induced by rapid rotation, and that a Rayleigh Jean's extrapolation of the stellar photosphere is not an adequate representation of a star's radio spectrum.

Keywords: Millimeter astronomy, Circumstellar matter, Radio continuum emission, Submillimeter astronomy, Stellar atmospheres