adsabs/SciX_UAT_keywords huggingface dataset:
The Distribution of Highly Red-sloped Asteroids in the Middle and Outer Main Belt

Red (S > 10%/0.1 μm) spectral slopes are common among Centaurs and trans-Neptunian objects (TNOs) in the outer solar system. Interior to and co-orbital with Jupiter, the red (S ∼ 10%/0.1 μm) slopes of D-type main-belt and Jupiter Trojan asteroids are thought to reflect their hypothesized shared origin with TNOs beyond the orbit of Jupiter. In order to quantify the abundance of red-sloped asteroids within the main belt, we conducted a survey using the NASA Infrared Telescope Facility and the Lowell Discovery Telescope. We followed up on 32 candidate red objects identified via spectrophotometry from the Sloan Digital Sky Survey's Moving Object Catalog to confirm their steep spectral slopes and determine their taxonomic classifications. We find that our criteria for identifying candidate red objects from the Moving Object Catalog result in a ∼50% confirmation rate for steeply red-sloped asteroids. We also compare our observations of main-belt asteroids to existing literature spectra of the Jupiter Trojans and steeply red-sloped main-belt asteroids. We show that some red-sloped asteroids have linearly increasing reflectance with increasing wavelength, while other red-sloped asteroids show a flattening in slope at longer near-infrared wavelengths, indicating a diversity among the population of spectrally red main-belt asteroids suggestive of a variety of origins among the population of steep-sloped asteroids.

Keywords: asteroids; main belt asteroids; ground-based astronomy; asteroid belt; small solar system bodies
Zwicky Transient Facility and Globular Clusters: The Period-Luminosity and Period-Wesenheit Relations for Anomalous Cepheids Supplemented with Large Magellanic Cloud Sample

We present the first gri-band period-luminosity (PL) and period-Wesenheit (PW) relations for the fundamental mode anomalous Cepheids. These PL and PW relations were derived from a combined sample of five anomalous Cepheids in globular cluster M92 and the Large Magellanic Cloud, both of which have distance accurate to ~1% available from literature. Our g-band PL relation is similar to the B-band PL relation as reported in previous study. We applied our PL and PW relations to anomalous Cepheids discovered in dwarf galaxy Crater II, and found a larger but consistent distance modulus than the recent measurements based on RR Lyrae. Our calibrations of gri-band PL and PW relations, even though less precise due to small number of anomalous Cepheids, will be useful for distance measurements to dwarf galaxies.

Keywords: globular star clusters; anomalous cepheid variable stars; sky surveys; distance indicators
The ALMA Survey of Star Formation and Evolution in Massive Protoclusters with Blue Profiles (ASSEMBLE): Core Growth, Cluster Contraction, and Primordial Mass Segregation

The Atacama Large Millimeter/submillimeter Array (ALMA) Survey of Star Formation and Evolution in Massive Protoclusters with Blue Profiles (ASSEMBLE) aims to investigate the process of mass assembly and its connection to high-mass star formation theories in protoclusters in a dynamic view. We observed 11 massive (M clump ≳ 103 M ⊙), luminous (L bol ≳ 104 L ⊙), and blue-profile (infall signature) clumps by ALMA with resolution of ~2200-5500 au (median value of 3500 au) at 350 GHz (870 μm). We identified 248 dense cores, including 106 cores showing protostellar signatures and 142 prestellar core candidates. Compared to early stage infrared dark clouds (IRDCs) by ASHES, the core mass and surface density within the ASSEMBLE clumps exhibited a significant increment, suggesting concurrent core accretion during the evolution of the clumps. The maximum mass of prestellar cores was found to be 2 times larger than that in IRDCs, indicating that evolved protoclusters have the potential to harbor massive prestellar cores. The mass relation between clumps and their most massive core (MMCs) is observed in ASSEMBLE but not in IRDCs, which is suggested to be regulated by multiscale mass accretion. The mass correlation between the core clusters and their MMCs has a steeper slope compared to that observed in stellar clusters, which can be due to fragmentation of the MMC and stellar multiplicity. We observe a decrease in core separation and an increase in central concentration as protoclusters evolve. We confirm primordial mass segregation in the ASSEMBLE protoclusters, possibly resulting from gravitational concentration and/or gas accretion.

Keywords: protoclusters; star formation; massive stars; interstellar medium; protostars; star forming regions
A Comparison of Star-forming Clumps and Tidal Tails in Local Mergers and High-redshift Galaxies

The Clusters, Clumps, Dust, and Gas in Extreme Star-forming Galaxies (CCDG) survey with the Hubble Space Telescope includes multiwavelength imaging of 13 galaxies less than 100 Mpc away, spanning a range of morphologies and sizes, from blue compact dwarfs to luminous infrared galaxies, all with star formation rates in excess of hundreds of solar masses per year. Images of seven merging galaxies in the CCDG survey were artificially redshifted to compare with galaxies at z = 0.5, 1, and 2. Most redshifted tails have surface brightnesses that would be visible at z = 0.5 or 1 but not at z = 2 due to cosmological dimming. Giant star clumps are apparent in these galaxies; the 51 measured have similar sizes, masses, and colors to clumps in observed high-z systems in the UDF, GEMS, GOODS, and CANDELS surveys. These results suggest that some clumpy high-z galaxies without observable tidal features could be the result of mergers. The local clumps also have the same star formation rate per unit area and stellar surface density as clumps observed at intermediate and high redshift, so they provide insight into the substructure of distant clumps. A total of 1596 star clusters brighter than MV = -9 were identified within the boundaries of the local clumps. The cluster magnitude distribution function is a power law with approximately the same slope (∼-1 for a plot of number versus log luminosity) for all the galaxies both inside and outside the clumps and independently of clump surface brightness.

Keywords: galaxy evolution; high-redshift galaxies; interacting galaxies; starburst galaxies
Gear Up for the Action Replay: Leveraging Lensing for Enhanced Gravitational-wave Early Warning

Premerger gravitational-wave (GW) sky localization of binary neutron star (BNS) and neutron star-black hole (NSBH) coalescence events would enable telescopes to capture precursors and electromagnetic (EM) emissions around the time of the merger. We propose an astrophysical scenario that could provide early-warning times of hours to days before coalescence with subarcsecond localization, provided that these events are gravitationally lensed. The key idea is that if the BNS/NSBH is lensed, then so is the host galaxy identified via the EM counterpart. From the angular separation of the lensed host galaxy images, as well as its redshift and the (foreground) lens redshift, we demonstrate that, for galaxy-scale lenses, we can predict the time delays/arrival time differences assuming a standard lens model. We further assess the feasibility and benefits of lensing as a tool for early warning in various GW observing runs of the LIGO-Virgo-Kagra network, including Voyager and the third-generation network. To that end, we study the effect of the limited angular resolution of the telescopes on our ability to predict the time delays. We find that with an angular resolution of 0.05″ we can predict time delays of >1 day with 1σ error bar of ${ \mathcal O }$ (hours) at best. We also construct realistic time delay distributions of detectable lensed BNSs/NSBHs to forecast the early-warning times we might expect in the observing scenarios we consider.

Keywords: gravitational waves; gravitational lensing
Solar Wind Turbulence from 1 to 45 au. II. Analysis of Inertial-range Fluctuations Using Voyager and ACE Observations

We examine both Voyager and Advanced Composition Explorer magnetic field measurements at frequencies that characterize the inertial range using traditional polarization techniques that are designed to characterize plasma waves. Although we find good agreement with both the anticipated spectral index of the power spectrum and the scaling of magnetic power with heliocentric distance, we do not find that the polarization analyses yield results that can be readily described by plasma wave theory. The fluctuations are not circularly polarized and there is a markedly reduced coherence between the components of the fluctuation. The degree of polarization is also generally low, although not as low as the coherence, and the minimum variance direction is essentially random. We conclude that traditional plasma wave theory may not offer a good description for inertial-range fluctuations.

Keywords: heliosphere; solar wind; magnetohydrodynamics
Discovery of Super-enriched Gas 1 Gyr after the Big Bang

Abundances of chemical elements in the interstellar and circumgalactic media of high-redshift galaxies offer important constraints on the nucleosynthesis by early generations of stars. Damped Lyα absorbers (DLAs) in spectra of high-redshift background quasars are excellent sites for obtaining robust measurements of element abundances in distant galaxies. Past studies of DLAs at redshifts z > 4 have measured abundances of ≲0.01 solar. Here we report the discovery of a DLA at z = 4.7372 with an exceptionally high degree of chemical enrichment. We estimate the H I column density in this absorber to be log (N H I/cm-2) = 20.48 ± 0.15. Our analysis shows unusually high abundances of carbon and oxygen ([C/H] = 0.88 ± 0.17, [O/H] = 0.71 ± 0.16). Such a high level of enrichment a mere 1.2 Gyr after the Big Bang is surprising because of insufficient time for the required amount of star formation. To our knowledge, this is the first supersolar absorber found at z > 4.5. We find the abundances of Si and Mg to be [Si/H] = $-{0.56}_{-0.35}^{+0.40}$ and [Mg/H] = ${0.59}_{-0.50}^{+0.27}$ , confirming the metal-rich nature of this absorber. By contrast, Fe shows a much lower abundance ([Fe/H] = $-{1.53}_{-0.15}^{+0.15}$ ). We discuss implications of our results for galactic chemical evolution models. The metallicity of this absorber is higher than that of any other known DLA and is >2 orders of magnitude above predictions of chemical evolution models and the N H I-weighted mean metallicity from previous studies at z > 4.5. The relative abundances (e.g., [O/Fe] = 2.29 ± 0.05, [C/Fe] = 2.46 ± 0.08) are also highly unusual compared to predictions for enrichment by early stars.

Keywords: galaxies; galaxy chemical evolution; quasar absorption line spectroscopy; galactic abundances; circumgalactic medium
Star Formation in a Strongly Magnetized Cloud

We study star formation in the Center Ridge 1 (CR1) clump in the Vela C giant molecular cloud, selected as a high column density region that shows the lowest level of dust continuum polarization-angle dispersion, likely indicating that the magnetic field is relatively strong. We observe the source with the Atacama Large Millimeter/submillimeter Array 7 m array at 1.05 and 1.3 mm wavelengths, which enable measurements of dust temperature, core mass, and astrochemical deuteration. A relatively modest number of 11 dense cores are identified via their dust continuum emission, with masses spanning from 0.17-6.7 ${M}_{\odot}$. Overall CR1 has a relatively low compact dense gas fraction compared with other typical clouds with similar column densities, which may be a result of the strong magnetic field and/or the very early evolutionary stage of this region. The deuteration ratios, ${D}_{\mathrm{frac}}$, of the cores, measured with ${{\rm{N}}}_{2}{{\rm{H}}}^{+}$ (3-2) and ${{\rm{N}}}_{2}{{\rm{D}}}^{+}$ (3-2) lines, span from 0.011-0.85, with the latter being one of the highest values yet detected. The level of deuteration appears to decrease with evolution from prestellar to protostellar phase. A linear filament, running approximately parallel with the large scale magnetic field orientation, is seen connecting the two most massive cores, each having CO bipolar outflows aligned orthogonally to the filament. The filament contains the most deuterated core, likely to be prestellar and located midway between the protostars. The observations permit measurement of the full deuteration structure of the filament along its length, which we present. We also discuss the kinematics and dynamics of this structure, as well as of the dense core population.

Keywords: molecular clouds; star formation; magnetic fields
Gaps and Rings in Protoplanetary Disks with Realistic Thermodynamics: The Critical Role of In-plane Radiation Transport

Many protoplanetary disks exhibit annular gaps in dust emission, which may be produced by planets. Simulations of planet-disk interaction aimed at interpreting these observations often treat the disk thermodynamics in an overly simplified manner, which does not properly capture the dynamics of planet-driven density waves driving gap formation. Here we explore substructure formation in disks using analytical calculations and hydrodynamical simulations that include a physically motivated prescription for radiative effects associated with planet-induced density waves. For the first time, our treatment accounts not only for cooling from the disk surface but also for radiation transport along the disk midplane. We show that this in-plane cooling, with a characteristic timescale typically an order of magnitude shorter than the one due to surface cooling, plays a critical role in density wave propagation and dissipation (we provide a simple estimate of this timescale). We also show that viscosity, at the levels expected in protoplanetary disks ( $\alpha \lesssim {10}^{-3}$ ), has a negligible effect on density wave dynamics. Using synthetic maps of dust continuum emission, we find that the multiplicity and shape of the gaps produced by planets are sensitive to the physical parameters—disk temperature, mass, and opacity—that determine the damping of density waves. Planets orbiting at $\lesssim 20\,\mathrm{au}$ produce the most diverse variety of gap/ring structures, although significant variation is also found for planets at $\gtrsim 50\,\mathrm{au}$ . By improving the treatment of the physics governing planet-disk coupling, our results present new ways of probing the planetary interpretation of annular substructures in disks.

Keywords: protoplanetary disks; planet formation; hydrodynamics
Evidence of a Strong 19.5 Hz Flux Oscillation in Swift BAT and Fermi GBM Gamma-Ray Data from GRB 211211A

The gamma-ray burst (GRB) GRB 211211A is believed to have occurred due to the merger of two neutron stars or a neutron star and a black hole, despite its duration of more than a minute. Subsequent analysis has revealed numerous interesting properties including the possible presence of a ∼22 Hz quasiperiodic oscillation (QPO) during precursor emission. Here we perform timing analysis of Fermi and Swift gamma-ray data on GRB 211211A and, although we do not find a strong QPO during the precursor, we do find an extremely significant 19.5 Hz flux oscillation, which has higher fractional amplitude at higher energies, in a ∼0.2 s segment beginning ∼1.6 s after the start of the burst. After presenting our analysis we discuss possible mechanisms for the oscillation.

Keywords: black holes; gamma-ray bursts; gamma-rays; neutron stars; relativistic binary stars
Flare Expansion to a Magnetic Rope Accompanied by Rare Radio Bursts

We present multispectral analysis (radio, Hα, ultraviolet (UV)/extreme ultraviolet (EUV), and hard X-ray) of a confined flare from 2015 March 12. This flare started within the active region NOAA 12 297 and then it expanded into a large preexisting magnetic rope embedded with a cold filament. The expansion started with several brightenings located along the rope. This process was accompanied by a group of slowly positively drifting bursts in the 0.8-2 GHz range. The frequency drift of these bursts was 45-100 MHz s-1. One of the bursts had an S-like form. During the brightening of the rope we observed a unique bright EUV structure transverse to the rope axis. The structure was observed in a broad range of temperatures and it moved along the rope with the velocity of about 240 km s-1. When the structure dissipated, we saw a plasma further following twisted threads in the rope. The observed slowly positively drifting bursts were interpreted considering particle beams and we show that one with the S-like form could be explained by the beam propagating through the helical structure of the magnetic rope. The bright structure transverse to the rope axis was interpreted considering line-of-sight effects and the dissipation-spreading process, which we found to be more likely.

Keywords: solar flares
X-Ray-luminous Supernovae: Threats to Terrestrial Biospheres

The spectacular outbursts of energy associated with supernovae (SNe) have long motivated research into their potentially hazardous effects on Earth and analogous environments. Much of this research has focused primarily on the atmospheric damage associated with the prompt arrival of ionizing photons within days or months of the initial outburst, and the high-energy cosmic rays that arrive thousands of years after the explosion. In this study, we turn the focus to persistent X-ray emission, arising in certain SNe that have interactions with a dense circumstellar medium and observed months and/or years after the initial outburst. The sustained high X-ray luminosity leads to large doses of ionizing radiation out to formidable distances. We assess the threat posed by these X-ray-luminous SNe for Earth-like planetary atmospheres; our results are rooted in the X-ray SN observations from Chandra, Swift-XRT, XMM-Newton, NuSTAR, and others. We find that this threat is particularly acute for SNe showing evidence of strong circumstellar interaction, such as Type IIn explosions, which have significantly larger ranges of influence than previously expected and lethal consequences up to ~50 pc away. Furthermore, X-ray-bright SNe could pose a substantial and distinct threat to terrestrial biospheres and tighten the Galactic habitable zone. We urge follow-up X-ray observations of interacting SNe for months and years after the explosion to shed light on the physical nature and full-time evolution of the emission and to clarify the danger that these events pose for life in our galaxy and other star-forming regions.

Keywords: supernovae; astrobiology; x-ray transient sources
Dynamical Coupling of a Mean-field Dynamo and Its Wind: Feedback Loop over a Stellar Activity Cycle

We focus on the connection between the internal dynamo magnetic field and the stellar wind. If the star has a cyclic dynamo, the modulations of the magnetic field can affect the wind, which, in turn, can back-react on the boundary conditions of the star, creating a feedback loop. We have developed a 2.5D numerical setup to model this essential coupling. We have implemented an alpha-omega mean-field dynamo in the PLUTO code and then coupled it to a spherical polytropic wind model via an interface composed of four grid layers with dedicated boundary conditions. We present here a dynamo model close to a young Sun with cyclic magnetic activity. First, we show how this model allows one to track the influence of the dynamo activity on the corona by displaying the correlation between the activity cycle, the coronal structure, and the time evolution of integrated quantities. Then we add the feedback of the wind on the dynamo and discuss the changes observed in the dynamo symmetry and wind variations. We explain these changes in terms of dynamo modes; in this parameter regime, the feedback loop leads to a coupling between the dynamo families via a preferred growth of the quadrupolar mode. We also study our interface in terms of magnetic helicity and show that it leads to a small injection in the dynamo. This model confirms the importance of coupling physically internal and external stellar layers, as it has a direct impact on both the dynamo and the wind.

Keywords: solar cycle; solar corona; solar dynamo; solar wind; magnetohydrodynamics
Fine Structure of a Solar Type II Radio Burst Observed by LOFAR

Shock waves in the solar corona are closely associated with coronal mass ejections and flares. The longest-known and frequently studied signatures of coronal shock waves are metric type II radio bursts, which provide information on the shock driver and ambient plasma conditions. We report on outstanding high frequency/time resolution LOw Frequency ARray (LOFAR) observations of a metric type II radio burst. The LOFAR observations show a strong fragmentation of the type II emission, in both the frequency and time domains, during the whole duration of the event. A very unusual splitting of an already-split type II band, which we call the band-split of the band-split, was observed for the first time. The richness of fine structure, observed in both the fundamental and harmonic bands of the type II emission, is unprecedented. Fine structures, morphologically similar to those seen superposed on a type IV continuum, were observed for the first time within a type II burst. We classify the fine structures into three categories: simple narrowband, broadband, and complex fine structures, and discuss their properties. LOFAR observations of fragmented shock-associated radio emission have the potential of bringing new insight into the physics of coronal shock waves, and also new challenges for the theory of electron acceleration by shocks.

Keywords: solar electromagnetic emission; solar physics; solar coronal waves; active solar corona; solar coronal mass ejection shocks; solar radio emission
A Hidden Population of Massive Black Holes in Simulated Dwarf Galaxies

We explore the characteristics of actively accreting massive black holes (MBHs) within dwarf galaxies in the ROMULUS25 cosmological hydrodynamic simulation. We examine the MBH occupation fraction, X-ray active fractions, and active galactic nucleus (AGN) scaling relations within dwarf galaxies of stellar mass 108 M ⊙ < M star < 1010 M ⊙ out to redshift z = 2. In the local universe, the MBH occupation fraction is consistent with observed constraints, dropping below unity at M star < 3 × 1010 M ⊙, M 200 < 3 × 1011 M ⊙. Local dwarf AGN in ROMULUS25 follow observed scaling relations between AGN X-ray luminosity, stellar mass, and star formation rate, though they exhibit slightly higher active fractions and number densities than comparable X-ray observations. Since z = 2, the MBH occupation fraction has decreased, the population of dwarf AGN has become overall less luminous, and as a result the overall number density of dwarf AGN has diminished. We predict the existence of a large population of MBHs in the local universe with low X-ray luminosities and high contamination from X-ray binaries and the hot interstellar medium that are undetectable by current X-ray surveys. These hidden MBHs make up 76% of all MBHs in local dwarf galaxies and include many MBHs that are undermassive relative to their host galaxy's stellar mass. Their detection relies on not only greater instrument sensitivity but also better modeling of X-ray contaminants or multiwavelength surveys. Our results indicate that dwarf AGN were substantially more active in the past, despite having low luminosity today, and that future deep X-ray surveys may uncover many hidden MBHs in dwarf galaxies out to at least z = 2.

Keywords: dwarf galaxies; active galaxies; hydrodynamical simulations; supermassive black holes