Sazuna/UAT_keywords huggingface dataset:
Strong Nongravitational Accelerations and the Potential for Misidentification of Near-Earth Objects. Nongravitational accelerations in the absence of observed activity have recently been identified on near-Earth objects (NEOs), opening the question of the prevalence of anisotropic mass loss in the near-Earth environment. Motivated by the necessity of nongravitational accelerations to identify 2010 VL65 and 2021 UA12 as a single object, we investigate the problem of linking separate apparitions in the presence of nongravitational perturbations. We find that nongravitational accelerations on the order of 1 × 10–9 au day‑2 can lead to a change in plane-of-sky positions of ∼1 × 103 arcsec between apparitions. Moreover, we inject synthetic tracklets of hypothetical nongravitationally accelerating NEOs into the Minor Planet Center orbit identification algorithms. We find that at large nongravitational accelerations (∣A  i ∣ ≥ 1 × 10‑8 au day‑2) these algorithms fail to link a significant fraction of these tracklets. We further show that if orbits can be determined for both apparitions, the tracklets will be linked regardless of nongravitational accelerations, although they may be linked to multiple objects. In order to aid in the identification and linkage of nongravitationally accelerating objects, we propose and test a new methodology to search for unlinked pairs. When applied to the current census of NEOs, we recover the previously identified case but identify no new linkages. We conclude that current linking algorithms are generally robust to nongravitational accelerations, but objects with large nongravitational accelerations may potentially be missed. While current algorithms are well-positioned for the anticipated increase in the census population from future survey missions, it may be possible to find objects with large nongravitational accelerations hidden in isolated tracklet pairs.

Keywords: Celestial mechanics, Comets, Near-Earth objects, Asteroids
Cracking the Relation between Mass and 1P-star Fraction of Globular Clusters. II. The Masses in 1P and 2P Stars as a Second Tool. Galactic globular clusters contain two main groups of stars, the pristine or 1P stars, and the polluted or 2P stars. The pristine-star fraction in clusters, F 1P , is a decreasing function of the cluster present-day mass, m prst. Paper I has introduced a model mapping the region of the (m prst, F 1P ) space occupied by clusters, with the cluster mass threshold for 2P-star formation a key building block. We now expand this model to the pristine-star fraction in dependence of the pristine- and polluted-population masses. A. P. Milone et al. found that F 1P  anticorrelates more tightly with the polluted-population present-day mass, m 2P,prst, than with the cluster total mass, m prst. By contrast, F 1P  anticorrelates poorly with the pristine-population current mass, m 1P,prst. We show the loose anticorrelation between F 1P  and m 1P,prst to result from a roughly constant pristine-population mass in clusters as they start their long-term evolution in the Galactic tidal field. As for the tight anticorrelation between m 2P,prst and F 1P , it stems from the initially shallow relation between m 2P  and F 1P . Clusters of the Large and Small Magellanic Clouds (LMC and SMC, respectively) appear to behave unexpectedly with respect to each other. For a given F 1P , LMC clusters are more massive than SMC clusters despite their enduring a stronger tidal field. This is opposite to how the Galactic outer- and inner-halo clusters behave. The explanation may lie in cluster formation conditions. Finally, we wonder whether the single-population clusters NGC 419 and Rup 106 formed as multiple-population clusters.

Keywords: Globular star clusters, Stellar populations, Stellar dynamics, Chemical abundances, Chemical enrichment, Population II stars, Magellanic Clouds, Milky Way Galaxy
Radial Distribution of Electron Quasi-thermal Noise in the Inner Heliosphere. The electron population in the solar wind plasma can be described with three different components: a core, a halo, and a magnetic field aligned strahl. The electron quasi-thermal noise (QTN) is investigated by using an electron population model consisting of a core with a Maxwellian distribution and a halo with a kappa distribution, based on the empirical equations for electron density and temperature and the index for the kappa halo. The power spectra of the electron QTN are calculated at different heliocentric radial distances from 10 to 200 R  s . The dependence of the QTN spectrum and effective Debye length on model parameters, including the ratio of the halo to the core for the density and temperature, the kappa index, and the antenna length, is further discussed. The results show that the electron QTN spectrum consists of a plateau in the low-frequency band f &lt; f  pt , a peak at the total plasma frequency f  pt , and a rapidly decreasing part in the high-frequency band f &gt; f  pt . The QTN peak and plateau level continuously decrease as the radial distance increases, with the peak's shape changing due to the variation of the kappa index. Although the model parameters are variable, the QTN plateau level presents less than an order of change with these parameters changing greatly, and only a monotonic change of the plateau is shown when the parameters are close to the practical situation. The results can provide a reference for future deep-space exploration in the inner heliosphere, and also for the design of detectors.

Keywords: Space plasmas, Solar wind, Interplanetary physics
Between the Extremes: A JWST Spectroscopic Benchmark for High-redshift Galaxies Using ∼500 Confirmed Sources at z ≥ 5. The exceptional spectra of the most luminous z &gt; 10 sources observed so far have challenged our understanding of early galaxy evolution, requiring a new observational benchmark for meaningful interpretation. As such, we construct spectroscopic templates representative of high-redshift, star-forming populations, using 482 confirmed sources at z = 5.0‑12.9 with JWST/NIRSpec prism observations, and report on their average properties. We find z = 5‑11 galaxies are dominated by blue UV continuum slopes (β = ‑2.3 to ‑2.7) and reduced Balmer indices, characteristic of dust-poor and young systems, with a shift towards bluer slopes and younger ages with redshift. The evolution is mirrored by ubiquitous C III] detections across all redshifts (rest-frame equivalent widths of 5‑14 Å), which increase in strength towards early times. Rest-frame optical lines reveal elevated ratios (O32 = 7–31, R23 = 5–8, and Ne3O2 = 1‑2) and subsolar metallicities (log(O/H) = 7.3‑7.9), typical of ionization conditions and metallicities rarely observed in z ∼ 0 populations. Within our sample, we identify 57 Lyα emitters, which we stack and compare to a matched sample of nonemitters. The former are characterized by more extreme ionizing conditions with enhanced C III], C IV, and He II + [O III] line emission, younger stellar populations from Balmer jumps, and a more pristine interstellar medium seen through bluer UV slopes and elevated rest-frame optical line ratios. The novel comparison illustrates important intrinsic differences between the two populations, with implications for Lyα visibility. The spectral templates derived here represent a new observational benchmark with which to interpret high-redshift sources, lifting our constraints on their global properties to unprecedented heights and extending out to the earliest of cosmic times.

Keywords: Early universe, Stellar ages, Galaxy evolution, Reionization, Metallicity, High-redshift galaxies
An In-depth Analysis of Quiet-Sun IRIS Brightenings. Small-scale brightenings are ubiquitous, dynamic, and energetic phenomena found in the chromosphere. An advanced filter-detection algorithm applied to high-resolution observations from the Interface Region Imaging Spectrograph enables the detection of these brightenings close to the noise level. This algorithm also tracks the movement of these brightenings and extracts their characteristics. This work outlines the results of an in-depth analysis of a quiet-Sun data set including a comparison of a brighter domain—associated with a supergranular boundary—to the quiescent internetwork domains. Several characteristics of brightenings from both domains are extracted and analysed, providing a range of sizes, durations, brightness values, travel distances, and speeds. The "active" quiet-Sun events tend to travel shorter distances and at slower speeds across the plane of the sky than their "true" quiet-Sun counterparts. These results are consistent with the magnetic field model of supergranular photospheric structures and the magnetic canopy model of the chromosphere above. Spectroscopic analyses reveal that bright points demonstrate blueshift (as well as some bidirectionality) and that they may rise from the chromosphere into the transition region. We believe that these bright points are magnetic in nature, are likely the result of magnetic reconnection, and follow current sheets between magnetic field gradients, rather than travel along magnetic field lines themselves.

Keywords: Solar chromosphere, Solar magnetic reconnection, Solar magnetic bright points, Quiet solar chromosphere
Multi-Observatory Research of Young Stellar Energetic Flares (MORYSEF): X-Ray-flare-related Phenomena and Multi-epoch Behavior. The most powerful stellar flares driven by magnetic energy occur during the early pre-main-sequence (PMS) phase. The Orion Nebula represents the nearest region populated by young stars, showing the greatest number of flares accessible to a single pointing of Chandra. This study is part of a multi-observatory project to explore stellar surface magnetic fields (with the Hobby–Eberly Telescope Habitable-zone Planet Finder, HET-HPF), particle ejections (with the Very Long Baseline Array, VLBA), and disk ionization (with the Atacama Large Millimeter/submillimeter Array, ALMA) immediately following the detection of PMS superflares with Chandra. In 2023 December, we successfully conducted such a multi-telescope campaign. Additionally, by analyzing Chandra data from 2003, 2012, and 2016, we examine the multi-epoch behavior of PMS X-ray emission related to PMS magnetic cyclic activity and ubiquitous versus sample-confined megaflaring. Our findings are as follows. (1) We report detailed stellar quiescent and flare X-ray properties for numerous HET/ALMA/VLBA targets, facilitating ongoing multiwavelength analyses. (2) For numerous moderately energetic flares, we report correlations (or lack thereof) between flare energies and stellar mass/size (presence/absence of disks) for the first time. The former is attributed to the correlation between convection-driven dynamo and stellar volume, while the latter suggests the operation of solar-type flare mechanisms in PMS stars. (3) We find that most PMS stars exhibit minor long-term baseline variations, indicating the absence of intrinsic magnetic dynamo cycles or observational mitigation of cycles by saturated PMS X-rays. (4) We conclude that X-ray megaflares are ubiquitous phenomena in PMS stars, which suggests that all protoplanetary disks and nascent planets are subject to violent high-energy emission and particle irradiation events.

Keywords: Stellar x-ray flares, Stellar magnetic fields, Pre-main sequence stars, Stellar flares, Protoplanetary disks, X-ray stars
Expanding the Inventory of Molecule-rich Planetary Nebulae: New Observations of M4-17, Hu 1-1, M1-59, and Na 2. Molecular observations of four planetary nebulae (PNe), M4-17, Hu 1-1, M1-59, and Na 2, were conducted at 1–3 mm using the Arizona Radio Observatory's 12 m antenna and Submillimeter Telescope, and the Institut de Radioastronomie Millimétrique 30 m Telescope. Toward M4-17, HNC (J = 3 → 2), CCH (N = 2 → 1, N = 3 → 2), CN (N = 1 → 0, N = 2 → 1), H2CO (J Ka,Kc = 21,2 → 11,1, J Ka,Kc = 20,2 → 10,1, J Ka,Kc = 21,1 → 11,0), CS (J = 3 → 2, J = 5 → 4), and H13CN (J = 2 → 1) were detected. An almost identical set of transitions was identified toward Hu 1-1. Moreover, c–C3H2 was detected in Hu 1-1 via three 2 mm lines: J Ka,Kc = 31,2 → 22,1, J Ka,Kc = 41,4 → 30,3, and J Ka,Kc = 32, 2 → 21,1. HNC, CCH, CN, CS, and H13CN were found in M1-59, as well as H2S via its J Ka,Kc = 11,0 → 10,1 line—the first detection of this key sulfur species in PNe. In addition, CCH and CN were identified in the 27,000 yr old Na 2. Among these four sources, CN and CCH were the most prevalent molecules (after CO and H2) with fractional abundances, relative to H2, of f ∼ 0.9–7.5 × 10‑7 and 0.8–7.5 × 10‑7, respectively. CS and HNC have abundances in the range f ∼ 0.5–5 × 10‑8, the latter resulting in HCN/HNC ∼ 3 across all three PNe. The unusual species H2CO, c–C3H2, and H2S had f ∼ 3–4 × 10‑7, 10‑8, and 6 × 10‑8. This study suggests that elliptical PNe such as Hu 1-1 can have a diverse molecular composition. The presence of CN, CCH, and HCO+ in Na 2, with comparable abundances to younger PNe, demonstrates that molecular content is maintained into the late PN stage.

Keywords: Interstellar molecules, Molecular spectroscopy, Astrochemistry, Planetary nebulae, Radio astronomy
Constraining the Low-mass End of the Stellar-to-halo Mass Relation with Surveys of Satellite Galaxies. The abundance of satellite galaxies is set by the hierarchical assembly of their host halo. We leverage this to investigate the low-mass end (M H &lt; 1011 M ⊙) of the stellar-to-halo mass relation (SHMR), which is key to constraining theories of galaxy formation and cosmology. We argue that recent analyses of satellite galaxies in the Local Group environment have not adequately modeled the dominant source of scatter in satellite stellar mass functions: the variance in accretion histories for a fixed host halo mass. We present a novel inference framework that not only properly accounts for this halo-to-halo variance but also naturally identifies the amount of host halo mass mixing, which is generally unknown. Specifically, we use the semianalytical SatGen model to construct mock satellite galaxy populations consistent with the third data release of the Satellites Around Galactic Analogs survey. We demonstrate that even under the most idealized circumstances, the halo-to-halo variance makes it virtually impossible to put any meaningful constraints on the scatter in the SHMR. Even a satellite galaxy survey made up 100 hosts can at best only place an upper limit of ∼0.5 dex on the scatter (at the 95% confidence level). This is because the large variance in halo assembly histories dominates over the scatter in the SHMR. This problem can be overcome by increasing the sample size of the survey by an order of magnitude (∼1000 host galaxies), something that should be fairly straightforward with forthcoming spectroscopic surveys.

Keywords: Galaxy dark matter halos, Dwarf galaxies, Galaxy abundances
Whole-disk Sampling of Molecular Clouds in M83. We present a catalog of clouds identified from the 12CO (1–0) data of M83, which was observed using the Atacama Large Millimeter/submillimeter Array with a spatial resolution of ∼46 pc and a mass sensitivity of ∼104 M ⊙ (3σ). The almost full-disk coverage and high sensitivity of the data allowed us to sample 5724 molecular clouds with a median mass of ∼1.9 × 105 M ⊙, which is comparable to the most frequently sampled mass of giant molecular clouds by surveys in the Milky Way (MW). About 60% of the total CO luminosity in M83's disk arises from clouds more massive than 106 M ⊙. Such massive clouds comprise 16% of the total clouds in number and tend to concentrate toward the arm, bar, and center, while smaller clouds are more prevalent in interarm regions. Most &gt;106 M ⊙ clouds have peak brightness temperatures T peak above 2 K with the current resolution. Comparing the observed cloud properties with the scaling relations determined by P. M. Solomon et al. (1987, hereafter S87), T peak &gt; 2 K clouds follow the relations, but T peak &lt; 2 K clouds, which are dominant in number, deviate significantly. Without considering the effect of beam dilution, the deviations would suggest modestly high virial parameters (median α vir ∼ 2.7) and low surface mass densities (median Σ ∼ 22 M ⊙ pc‑2) for the entire cloud samples, which are similar to values found for the MW clouds by T. S. Rice et al. (2016) and M.-A Miville-Deschênes et al. (2017). However, once beam dilution is taken into account, the observed α vir and Σ for a majority of the clouds (mostly T peak &lt;2 K) can be potentially explained with intrinsic Σ of ∼100 M ⊙ pc‑2 and α vir of ∼1, which are similar to the clouds of S87.

Keywords: Spiral galaxies, Millimeter astronomy, Giant molecular clouds, Interstellar medium, CO line emission
A Search for Persistent Radio Sources toward Repeating Fast Radio Bursts Discovered by CHIME/FRB. The identification of persistent radio sources (PRSs) coincident with two repeating fast radio bursts (FRBs) supports FRB theories requiring a compact central engine. However, deep nondetections in other cases highlight the diversity of repeating FRBs and their local environments. Here, we perform a systematic search for radio sources towards 37 CHIME/FRB repeaters using their arcminute localizations and a combination of archival surveys and targeted observations. Through multiwavelength analysis of individual radio sources, we identify two (20181030A-S1 and 20190417A-S1) for which we disfavor an origin of either star formation or an active galactic nucleus in their host galaxies and thus consider them candidate PRSs. We do not find any associated PRSs for the majority of the repeating FRBs in our sample. For eight FRB fields with Very Large Array imaging, we provide deep limits on the presence of PRSs that are 2─4 orders of magnitude fainter than the PRS associated with FRB 20121102A. Using Very Large Array Sky Survey imaging of all 37 fields, we constrain the rate of luminous (≳1040 erg s−1) PRSs associated with repeating FRBs to be low. Within the context of FRB-PRS models, we find that 20181030A-S1 and 20190417A-S1 can be reasonably explained within the context of magnetar, hypernebulae, gamma-ray burst afterglow, or supernova ejecta models—although we note that both sources follow the radio luminosity versus rotation measure relationship predicted in the nebula model framework. Future observations will be required to both further characterize and confirm the association of these PRS candidates with the FRBs.

Keywords: Transient sources, Radio sources, Radio transient sources
Disk2Planet: A Robust and Automated Machine Learning Tool for Parameter Inference in Disk–Planet Systems. We introduce Disk2Planet, a machine-learning-based tool to infer key parameters in disk–planet systems from observed protoplanetary disk structures. Disk2Planet takes as input the disk structures in the form of 2D density and velocity maps, and outputs disk and planet properties, that is, the Shakura–Sunyaev viscosity, the disk aspect ratio, the planet–star mass ratio, and the planet's radius and azimuth. We integrate the Covariance Matrix Adaptation Evolution Strategy, an evolutionary algorithm tailored for complex optimization problems, and the Protoplanetary Disk Operator Network, a neural network designed to predict solutions of disk–planet interactions. Our tool is fully automated and can retrieve parameters in one system in 3 minutes on an Nvidia A100 graphics processing unit. We empirically demonstrate that our tool achieves percent-level or higher accuracy, and is able to handle missing data and unknown levels of noise.

Keywords: Hydrodynamical simulations, Planetary-disk interactions, Protoplanetary disks, Neural networks
Constraining Quasar Feedback from Analysis of the Hydrostatic Equilibrium of the Molecular Gas in Their Host Galaxies. We investigate the kinematics and dynamics of the molecular and ionized gas in the host galaxies of three Palomar-Green quasars at low redshifts, benefiting from the archival millimeter-wave interferometric and optical integral field unit data. We study the kinematics of both cold molecular and hot ionized gas by analyzing the CO and Hα data cubes, and construct the mass distributions of our sample through gas dynamics, utilizing a priori knowledge regarding the galaxy light distribution. We find no systematic offset between the stellar mass derived from our dynamical method and that from the broadband photometry and mass-to-light ratio, suggesting the consistency of both methods. We then study the kinetic pressure and the weight of the interstellar medium (ISM) using our dynamical mass model. By studying the relationship between kinetic pressure and gravitational pressure of the quasar host galaxies, we find an equivalence in the hydrostatic equilibrium states of ISM in the quasar host galaxies, similar to the result of gas equilibrium in normal star-forming galaxies, suggesting minimal quasar feedback. Regarding noncircular motion as indicative of quasar-driven outflows, we observe an exceptionally low coupling efficiency between molecular gas outflow and active galactic nucleus bolometric luminosities. These results demonstrate the marginal influence of the central engine on the properties of cold molecular gas in quasar host galaxies.

Keywords: AGN host galaxies, Molecular gas, Quasars, Galaxy dynamics, Galaxy kinematics
Puffy Venuses: The Mass–Radius Impact of Carbon-rich Atmospheres on Lava Worlds. The recent advancements in exoplanet observations enable the potential detection of exo-Venuses, rocky planets with carbon-rich atmospheres. How extended these atmospheres can be, given high carbon abundances, has not been studied. To answer this, we present a model for a theoretical class of exoplanets—puffy Venuses—characterized by thick, carbon-dominated atmospheres in equilibrium with global magma oceans (MOs). Our model accounts for carbon and hydrogen partition between the atmosphere and the MO, as well as the C–H–O equilibrium chemistry throughout a semi-gray, radiative-convective atmosphere. We find that radius inflation by puffy Venus atmospheres is significant on small and irradiated planets: carbon content of 1200 ppm (or that of ordinary chondrites) can generate an atmosphere of ∼0.16–0.3 R ⊕ for an Earth-mass planet with equilibrium temperatures of 1500–2000 K. We identify TOI-561 b as an especially promising puffy Venus candidate, whose underdensity could be attributed to a thick C-rich atmosphere. We also advocate for a puffy Venus interpretation of 55 Cancri e, where a recent JWST observation indicates the presence of a CO/CO2 atmosphere. Puffy Venuses may thus constitute a testable alternative interpretation for the interior structure of underdense low-mass exoplanets.

Keywords: Extrasolar rocky planets, Exoplanet atmospheric composition , Exoplanets, Exoplanet astronomy, Planetary interior, Chemical reaction network models, Exoplanet atmospheres, Exoplanet atmospheric structure