Sazuna/UAT_keywords huggingface dataset:
Supernova Remnants in M83 as Observed with MUSE. Here we describe a new study of the supernova remnants (SNRs) and SNR candidates in nearby face-on spiral galaxy M83, based primarily on MUSE integral field spectroscopy. Our revised catalog of SNR candidates in M83 has 366 objects, 81 of which are reported here for the first time. Of these, 229 lie within the MUSE observation region, 160 of which have spectra with [S II]:Hα ratios exceeding 0.4, the value generally accepted as confirmation that an emission nebula is shock-heated. Combined with 51 SNR candidates outside the MUSE region with high [S II]:Hα ratios, there are 211 spectroscopically confirmed SNRs in M83, the largest number of confirmed SNRs in any external galaxy. MUSE's combination of relatively high spectral resolution and broad wavelength coverage has allowed us to explore two other properties of SNRs that could serve as the basis of future SNR searches. Specifically, most of the objects identified as SNRs on the basis of [S II]:Hα ratios exhibit more velocity broadening and lower ratios of [S III]:[S II] emission than H II regions. A search for nebulae with the very broad emission lines expected from young, rapidly expanding remnants revealed none, except for the previously identified B12-174a. The SNRs identified in M83 are, with few exceptions, middle-aged interstellar medium (ISM) dominated ones. Smaller-diameter candidates show a larger range of velocity broadening and a larger range of gas densities than the larger-diameter objects, as expected if the SNRs expanding into denser gas brighten and then fade from view at smaller diameters than those expanding into a more tenuous ISM.

Keywords: Supernova remnants, Interstellar medium
Variability of the Incompressible Energy Cascade Rate in Solar Wind Turbulence around Mars. We present a statistical analysis on the variability of the incompressible energy cascade rate in the solar wind around Mars, making use of an exact relation for fully developed turbulence and more than five years of Mars Atmosphere and Volatile EvolutioN (MAVEN) observations. Using magnetic field and plasma data, we compute the energy cascade rate at the magnetohydrodynamics (MHD) scales in the pristine solar wind. From our statistical results, we conclude that the incompressible energy cascade rate decreases as the Martian heliocentric distance increases, for each of the three explored Martian years. Moreover, we suggest that the presence of proton cyclotron waves, associated with the extended Martian hydrogen exosphere, do not have a significant effect on the nonlinear cascade of energy at the MHD scales.

Keywords: Interplanetary turbulence, Solar wind, Plasma physics
Formation of Coronal Mass Ejection and Posteruption Flow of Solar Wind on 2010 August 18 Event. The state of the space environment plays a significant role in the forecasting of geomagnetic storms produced by disturbances of the solar wind (SW). Coronal mass ejections (CMEs) passing through the heliosphere often have a prolonged (up to several days) trail with declining speed, which affects propagation of the subsequent SW streams. We studied the CME and posteruption plasma flows behind the CME rear in the event on 2010 August 18 that was observed in quadrature by several space-based instruments. Observations of the eruption in the corona with EUV telescopes and coronagraphs revealed several discrete outflows followed by a continuous structureless posteruption stream. The interplanetary coronal mass ejection (ICME) associated with this CME was registered by the Plasma and Suprathermal Ion Composition instrument aboard the Solar Terrestrial Relations Observatory between August 20, 16:14 UT and August 21, 13:14 UT, after which the SW disturbance was present over 3 days. Kinematic consideration with the use of the gravitational and drag-based models has shown that the discrete plasma flows can be associated with the ICME, whereas the posteruption outflow arrived in the declining part of the SW transient. We simulated the Fe ion charge distributions of the ICME and post-CME parts of the SW using the plasma temperature and density in the ejection region derived from the differential emission measure analysis. The results demonstrate that in the studied event, the post-ICME trailing region was associated with the posteruption flow from the corona rather than with the ambient SW entrained by the CME.

Keywords: Solar coronal mass ejections, Solar physics, Solar wind, Solar corona
A Population of Luminous Globular Clusters and Stripped Nuclei with Elevated Mass to Light Ratios around NGC 5128. The dense central regions of tidally disrupted galaxies can survive as ultracompact dwarfs (UCDs) that hide among the luminous globular clusters (GCs) in the halo of massive galaxies. An exciting confirmation of this model is the detection of overmassive black holes in the centers of some UCDs, which also lead to elevated dynamical mass-to-light ratios (M/L dyn). Here we present new high-resolution spectroscopic observations of 321 luminous GC candidates in the massive galaxy NGC 5128/Centaurus A. Using these data we confirm 27 new luminous GCs, and measure velocity dispersions for 57 luminous GCs (with g-band luminosities between 2.5 × 105 and 2.5 × 107 L ⊙), of which 48 are new measurements. Combining these data with size measurements from Gaia, we determine the M/L dyn for all 57 luminous GCs. We see a clear bimodality in the M/L dyn distribution, with a population of normal GCs with mean M/L dyn = 1.51 ± 0.31, and a second population of ~20 GCs with elevated mean M/L dyn = 2.68 ± 0.22. We show that black holes with masses ~4%-18% of the luminous GCs can explain the elevated mass-to-light ratios. Hence, it is plausible that the NGC 5128 sources with elevated M/L dyn are mostly stripped galaxy nuclei that contain massive central black holes, though future high spatial resolution observations are necessary to confirm this hypothesis for individual sources. We also present a detailed discussion of an extreme outlier, VHH81-01, one of the largest and most massive GC in NGC 5128, making it an exceptionally strong candidate to be a tidally stripped nucleus. * This paper includes data gathered with the 6.5 m Magellan Telescope at Las Campanas Observatory, Chile.

Keywords: Globular star clusters, Stellar kinematics, Stellar dynamics, Galaxy nuclei, Mass-to-light ratio, Ultracompact dwarf galaxies
Carbon Abundances in Compact Galactic Planetary Nebulae: An Ultraviolet Spectroscopic Study with the Space Telescope Imaging Spectrograph (STIS). We surveyed a sample of compact Galactic planetary nebulae (PNe) with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope (HST) to determine their gas-phase carbon abundances. Carbon abundances in PNe constrain the nature of their asymptotic giant branch (AGB) progenitors, as well as cosmic recycling. We measured the carbon abundances, or the limits thereof, of 11 compact Galactic PNe, notably increasing the sample of Galactic PNe whose carbon abundance based on HST ultraviolet spectra is available. The dust content of most targets has been studied elsewhere from Spitzer spectroscopy; given the compact nature of the nebulae, both UV and IR spectra can be directly compared to study gas- and dust-phase carbon. We found that carbon-poor (C/O &lt; 1) compact Galactic PNe have an oxygen-rich dust type, while their carbon-enhanced counterparts (C/O &gt; 1) have carbon-rich dust, confirming the correlation between gas- and dust-phase carbon content that was known for Magellanic Cloud PNe. Based on models of expected final yields from AGB evolution, we interpret the majority of the carbon-poor PNe in this study as the progeny of ~1.1-1.2 M ⊙ stars that experienced some extra mixing on the red giant branch. They went through the AGB but did not go through the carbon star phase. Most PNe in this group have a bipolar morphology, possibly due to the presence of a subsolar companion. The carbon-enhanced PNe in our sample could be the progeny of stars in the ~1.5-2.5 M ⊙ range, depending on their original metallicity.

Keywords: Planetary nebulae
A Coronal Mass Ejection and Magnetic Ejecta Observed In Situ by STEREO-A and Wind at 55° Angular Separation. We present an analysis of in situ and remote-sensing measurements of a coronal mass ejection (CME) that erupted on 2021 February 20 and impacted both the Solar TErrestrial RElations Observatory (STEREO)-A and the Wind spacecraft, which were separated longitudinally by 55°. Measurements on 2021 February 24 at both spacecraft are consistent with the passage of a magnetic ejecta (ME), making this one of the widest reported multispacecraft ME detections. The CME is associated with a low-inclined and wide filament eruption from the Sun's southern hemisphere, which propagates between STEREO-A and Wind around E34. At STEREO-A, the measurements indicate the passage of a moderately fast (~425 km s-1) shock-driving ME, occurring 2-3 days after the end of a high speed stream (HSS). At Wind, the measurements show a faster (~490 km s-1) and much shorter ME, not preceded by a shock nor a sheath, and occurring inside the back portion of the HSS. The ME orientation measured at both spacecraft is consistent with a passage close to the legs of a curved flux rope. The short duration of the ME observed at Wind and the difference in the suprathermal electron pitch-angle data between the two spacecraft are the only results that do not satisfy common expectations. We discuss the consequence of these measurements on our understanding of the CME shape and extent and the lack of clear signatures of the interaction between the CME and the HSS.

Keywords: Interplanetary magnetic fields, Interplanetary physics, Solar coronal mass ejections, Heliosphere
Damped Lyα Absorbers in Star-forming Galaxies at z &lt; 0.15 Detected with the Hubble Space Telescope and Implications for Galactic Evolution. We report Hubble Space Telescope Cosmic Origins Spectrograph spectroscopy of 10 quasars with foreground star-forming galaxies at 0.02 &lt; z &lt; 0.14 within impact parameters of ~1-7 kpc. We detect damped/sub-damped Lyα (DLA/sub-DLA) absorption in 100% of cases where no higher-redshift Lyman-limit systems extinguish the flux at the expected wavelength of Lyα absorption, obtaining the largest targeted sample of DLA/sub-DLAs in low-redshift galaxies. We present absorption measurements of neutral hydrogen and metals. Additionally, we present Green Bank Telescope 21 cm emission measurements for five of the galaxies (including two detections). Combining our sample with the literature, we construct a sample of 117 galaxies associated with DLA/sub-DLAs spanning 0 &lt; z &lt; 4.4, and examine trends between gas and stellar properties, and with redshift. The H I column density is anticorrelated with impact parameter and stellar mass. More massive galaxies appear to have gas-rich regions out to larger distances. The specific star formation rate (sSFR) of absorbing galaxies increases with redshift and decreases with M*, consistent with evolution of the star formation main sequence (SFMS). However, ~20% of absorbing galaxies lie below the SFMS, indicating that some DLA/sub-DLAs trace galaxies with longer-than-typical gas-depletion timescales. Most DLA/sub-DLA galaxies with 21 cm emission have higher H I masses than typical galaxies with comparable M*. High M HI/M* ratios and high sSFRs in DLA/sub-DLA galaxies with M* &lt; 109 M ⊙ suggest these galaxies may be gas-rich because of recent gas accretion rather than inefficient star formation. Our study demonstrates the power of absorption and emission studies of DLA/sub-DLA galaxies for extending galactic evolution studies to previously under-explored regimes of low M* and low SFR.

Keywords: Quasar absorption line spectroscopy, Observational cosmology, Star formation, Galaxy evolution, Interstellar medium
Constraining Warm Dark Matter and Population III Stars with the Global 21 cm Signal. Upcoming ground- and space-based experiments may have sufficient accuracy to place significant constraints upon high-redshift star formation, Reionization, and dark matter (DM) using the global 21 cm signal of the intergalactic medium. In the early universe, when the relative abundance of low-mass DM halos was important, measuring the global signal would place constraints on the damping of structure formation caused by DM having a higher relic velocity (warm dark matter, or WDM) than in cold dark matter. Such damping, however, can be mimicked by altering the star formation efficiency (SFE) and can be difficult to detect because of the presence of Population III stars with unknown properties. We study these various cases and their degeneracies with the WDM mass parameter m X using a Fisher matrix analysis. We study the m X = 7 keV case and a star formation model that parameterizes the SFE as a strong function of halo mass and include several variations of this model along with three different input noise levels for the likelihood; we also use a minimum halo virial temperature for collapse near the molecular cooling threshold. We find that when the likelihood includes only Population II stars, m X is constrained to an uncertainty of ~0.4 keV for all models and noise levels at the 68% confidence level. When the likelihood includes weak Population III stars, m X ~ 0.3 keV, and if Population III star formation is relatively efficient, m X ~ 0.1 keV uncertainty, with tight Population III star formation parameter constraints. Our results show that the global 21 cm signal is a promising test-bed for WDM models, even in the presence of strong degeneracies with astrophysical parameters.

Keywords: Cosmology, Warm dark matter, Population III stars, Large-scale structure of the universe, Observational cosmology, Star formation, Dark matter
Galaxy Light Profile Convolutional Neural Networks (GaLNets). I. Fast and Accurate Structural Parameters for Billion-galaxy Samples. Next-generation large sky surveys will observe up to billions of galaxies for which basic structural parameters are needed to study their evolution. This is a challenging task that, for ground-based observations, is complicated by seeing-limited point-spread functions (PSFs). To perform a fast and accurate analysis of galaxy surface brightness, we have developed a family of supervised convolutional neural networks (CNNs) to derive Sérsic profile parameters of galaxies. This work presents the first two Galaxy Light profile CNNs (GaLNets) of this family. The first one is trained using galaxy images only (GaLNet-1), and the second is trained with both galaxy images and the local PSF (GaLNet-2). We have compared the results from GaLNets with structural parameters (total magnitude, effective radius, Sérsic index, etc.) derived from a set of galaxies from the Kilo-Degree Survey by 2DPHOT as a representative of the "standard" PSF-convolved Sérsic fitting tools. The comparison shows that GaLNet-2 can reach an accuracy as high as that of 2DPHOT, while GaLNet-1 performs worse because it misses the information from the local PSF. Both GaLNets are three orders of magnitude faster than standard methods in terms of computational speed. This first application of CNNs to ground-based galaxy surface photometry shows that they are promising tools to perform parametric analyses of very large galaxy samples, like the ones expected from the Vera Rubin/LSST surveys. However, GaLNets can be easily modified for space observations from Euclid and the China Space Station Telescope.

Keywords: Galaxy formation, Galaxy structure, Neural networks
Cloud-convection Feedback in Brown Dwarf Atmospheres. Numerous observational evidence has suggested the presence of active meteorology in the atmospheres of brown dwarfs. A near-infrared brightness variability has been observed. Clouds have a major role in shaping the thermal structure and spectral properties of these atmospheres. The mechanism of such variability is still unclear, and neither 1D nor global circulation models can fully study this topic due to resolution. In this study, a convective-resolving model is coupled to gray-band radiative transfer in order to study the coupling between the convective atmosphere and the variability of clouds over a large temperature range with a domain of several hundred kilometers. Six types of clouds are considered, with microphysics including settling. The clouds are radiatively active through the Rosseland mean coefficient. Radiative cloud feedback can drive spontaneous atmospheric variability in both temperature and cloud structure, as modeled for the first time in three dimensions. Silicate clouds have the most effect on the thermal structure with the generation of a secondary convective layer in some cases, depending on the assumed particle size. Iron and aluminum clouds also have a substantial impact on the atmosphere. Thermal spectra were computed, and we find the strongest effect of the clouds is the smoothing of spectral features at optical wavelengths. Compared to observed L and T dwarfs on the color-magnitude diagram, the simulated atmospheres are redder for most of the cases. Simulations with the presence of cloud holes are closer to observations.

Keywords: Brown dwarfs
After The Fall: Resolving the Molecular Gas in Post-starburst Galaxies. Post-starburst (PSB), or "E + A," galaxies represent a rapid transitional phase between major, gas-rich mergers and gas-poor, quiescent, early-type galaxies. Surprisingly, many PSBs have been shown to host a significant interstellar medium (ISM), despite theoretical predictions that the majority of the star-forming gas should be expelled in active galactic nuclei- or starburst-driven outflows. To date, the resolved properties of this surviving ISM have remained unknown. We present high-resolution ALMA continuum and CO(2-1) observations in six gas- and dust-rich PSBs, revealing for the first time the spatial and kinematic structure of their ISM on sub-kpc scales. We find extremely compact molecular reservoirs, with dust and gas surface densities rivaling those found in (ultra)luminous infrared galaxies. We observe spatial and kinematic disturbances in all sources, with some also displaying disk-like kinematics. Estimates of the internal turbulent pressure in the gas exceed those of normal star-forming disks by at least 2 orders of magnitude, and rival the turbulent gas found in local interacting galaxies, such as the Antennae. Though the source of this high turbulent pressure remains uncertain, we suggest that the high incidence of tidal disruption events in PSBs could play a role. The star formation in these PSBs' turbulent central molecular reservoirs is suppressed, forming stars only 10% as efficiently as starburst galaxies with similar gas surface densities. "The fall" of star formation in these galaxies was not precipitated by complete gas expulsion or redistribution. Rather, this high-resolution view of PSBs' ISM indicates that star formation in their remaining compact gas reservoirs is suppressed by significant turbulent heating.

Keywords: Molecular gas, Dust continuum emission, Galaxy evolution, Galaxy quenching, Post-starburst galaxies
Numerical Simulations of Convective Three-dimensional Red Supergiant Envelopes. We explore the three-dimensional properties of convective, luminous (L ≈ 104.5-105 L ⊙), hydrogen-rich envelopes of red supergiants (RSGs) based on radiation hydrodynamic simulations in spherical geometry using Athena++. These computations comprise ≈30% of the stellar volume, include gas and radiation pressure, and self-consistently track the gravitational potential for the outer ≈3M ⊙ of the simulated M ≈ 15M ⊙ stars. This work reveals a radius, R corr, around which the nature of the convection changes. For r &gt; R corr, though still optically thick, diffusion of photons dominates the energy transport. Such a regime is well studied in less luminous stars, but in RSGs, the near- (or above-)Eddington luminosity (due to opacity enhancements at ionization transitions) leads to the unusual outcome of denser regions moving outward rather than inward. This region of the star also has a large amount of turbulent pressure, yielding a density structure much more extended than 1D stellar evolution predicts. This "halo" of material will impact predictions for both shock breakout and early lightcurves of Type IIP supernovae. Inside of R corr, we find a nearly flat entropy profile as expected in the efficient regime of mixing-length theory (MLT). Radiation pressure provides ≈1/3 of the support against gravity in this region. Our comparisons to MLT suggest a mixing length of α = 3-4, consistent with the sizes of convective plumes seen in the simulations. The temporal variability of these 3D models is mostly on the timescale of the convective plume lifetimes (≈300 days), with amplitudes consistent with those observed photometrically.

Keywords: Stellar convection envelopes, Hydrodynamics, Red supergiant stars, Radiative transfer, Supergiant stars, Astronomical simulations
The Transformation of Centaurs into Jupiter-family Comets. Centaurs are an ephemeral class of objects that can evolve into Jupiter-family comets (or JFCs) due to gravitational perturbations from the giant planets. In this work, we use numerical integration of massless test particles in the six-body problem (the Sun, four giant planets, and a test particle) to study the transformation of Centaurs into JFCs. We find that Centaurs can transform into JFCs via a rapid, continuous drop in perihelion or aphelion distance to a value below 5.2 au or 7 au, respectively, typically within 5 yr from the start of the drop. We call these JFC perihelion drops and JFC aphelion drops, respectively. These drops are correlated with close approaches to Jupiter. For such perihelion and aphelion drops, the maximum possible fractional change in the associated perihelion or aphelion distance increases with decreasing close-approach distance to Jupiter. A perihelion barrier may exist at 6.3 au. If so, then it must be crossed from above in order for a Centaur to transform into a JFC due to a single close approach to Jupiter. Currently, 93 (or 11%) of the known Centaurs have a perihelion distance, q, below 6.3 au. If the inclination of the orbit of the Centaur to the ecliptic plane is above 10.°2, then orbits with q &gt; 6.3 au and 2 &lt; T  J  &lt; 3 can exist, where T  J  is the Tisserand parameter with respect to Jupiter. Small bodies in such orbits could be classified as either Centaurs or JFCs.

Keywords: Small Solar System bodies, Centaur group, Short period comets, Comet dynamics, Comets
Oxygen-enhanced Extremely Metal-poor Damped Lyα Systems: A Signpost of the First Stars?. We present precise abundance determinations of two near-pristine damped Lyα systems (DLAs) to assess the nature of the [O/Fe] ratio at [Fe/H] &lt; -3.0 (i.e., &lt;1/1000 of the solar metallicity). Prior observations indicate that the [O/Fe] ratio is consistent with a constant value, [O/Fe] ≃ +0.4, when -3 &lt; [Fe/H] &lt; -2, but this ratio may increase when [Fe/H] ≲ -3. In this paper, we test this picture by reporting new, high-precision [O/Fe] abundances in two of the most metal-poor DLAs currently known. We derive values of [O/Fe] = +0.50 ± 0.10 and [O/Fe] = +0.62 ± 0.05 for these two z ≃ 3 near-pristine gas clouds. These results strengthen the idea that the [O/Fe] abundances of the most metal-poor DLAs are elevated compared to DLAs with [Fe/H] ≳ -3. We compare the observed abundance pattern of the latter system to the nucleosynthetic yields of Population III supernovae (SNe), and find that the enrichment can be described by a (19-25) M☉ Population III SN that underwent a (0.9-2.4) × 1051 erg explosion. These high-precision measurements showcase the behavior of [O/Fe] in the most metal-poor environments. Future high-precision measurements in new systems will contribute to a firm detection of the relationship between [O/Fe] and [Fe/H]. These data will reveal whether we are witnessing a chemical signature of enrichment from Population III stars and allow us to rule out contamination from Population II stars.

Keywords: Population III stars, Damped Lyman-alpha systems, Chemical abundances, Intergalactic medium, Population II stars