Sazuna/UAT_keywords huggingface dataset:
Heavy-ion Acceleration in <SUP>3</SUP>He-rich Solar Energetic Particle Events: New Insights from Solar Orbiter. We present Solar Orbiter energetic particle observations of two 3He-rich events with features more clearly observed than in prior studies. The event of 2022 November 9 observed from 0.59 au contained hundreds of ultraheavy (UH; mass &gt;78 amu) ions whereas previous observations at 1 au have shown only an occasional count or two. The event of 2023 April 8 observed from 0.29 au fortuitously had very low ambient activity, making it possible to observe spectra from the 3He acceleration mechanism without contamination, revealing extremely low H and 4He intensities arriving simultaneously with other ions observed in typical 3He-rich events. Taken together with previous studies, we believe these data show that 3He-rich events have a single acceleration mechanism that is responsible for the unique abundance features of 3He, heavy ions, and UH ions. Considering the acceleration model of Roth &amp; Temerin that heats the ions over a broad range of gyrofrequencies away from those damped by H and 4He, we calculate reasonable fits to the observed abundances O-Fe. A key result is that high values of, e.g., Fe/O typical of such events is not due to preferential Fe heating, but on the contrary is due mainly to the depletion of O, which at elevated temperatures has a charge-to-mass ratio in the region of the waves damped by 4He. The model also naturally incorporates features of high-ionization states and neutron-rich isotope enhancements that have been long-standing puzzles in observations of this type of flare.

Keywords: Solar flares, Solar magnetic reconnection, Solar energetic particles, Solar abundances, Solar magnetic fields, Solar particle emission
The Accretion History of EX Lup: A Century of Bursts, Outbursts, and Quiescence. EX Lup is the archetype for the class of young stars that undergoes repeated accretion outbursts of ~5 mag at optical wavelengths that last for months. Despite extensive monitoring that dates back 130 yr, the accretion history of EX Lup remains mostly qualitative and has large uncertainties. We assess historical accretion rates of EX Lup by applying correlations between optical brightness and accretion, developed on multi-band magnitude photometry of the ~2 mag optical burst in 2022. Two distinct classes of bursts occur: major outbursts (∆V ~ 5 mag) have year-long durations, are rare, reach accretion rates of ${\dot{M}}_{\mathrm{acc}}\sim {10}^{-7}$ M ☉ yr-1 at peak, and have a total accreted mass of around 0.1 Earth mass. The characteristic bursts (∆V ~ 2 mag) have durations of ~2-3 months, are more common, reach accretion rates of ${\dot{M}}_{\mathrm{acc}}\sim {10}^{-8}$ M ☉ yr-1 at peak, and have a total accreted mass of around 10-3 Earth masses. The distribution of total accreted mass in the full set of bursts is poorly described by a power law, which suggests different driving causes behind the major outburst and characteristic bursts. The total mass accreted during two classes of bursts is around 2 times the masses accreted during quiescence. Our analysis of the light curves reveals a color-dependent time lag in the 2022 post-burst light curve, attributed to the presence of both hot and cool spots on the stellar surface.

Keywords: Light curves, Eruptive variable stars, Stellar accretion, Classical T Tauri stars
Recurring Activity Discovered on Quasi-Hilda 2009 DQ118. We have discovered two epochs of activity on quasi-Hilda 2009 DQ118. Small bodies that display comet-like activity, such as active asteroids and active quasi-Hildas, are important for understanding the distribution of water and other volatiles throughout the solar system. Through our NASA Partner Citizen Science project, Active Asteroids, volunteers classified archival images of 2009 DQ118 as displaying comet-like activity. By performing an in-depth archival image search, we found over 20 images from UT 2016 March 8-9 with clear signs of a comet-like tail. We then carried out follow-up observations of 2009 DQ118 using the 3.5 m Astrophysical Research Consortium Telescope at Apache Point Observatory, Sunspot, New Mexico, USA and the 6.5 m Magellan Baade Telescope at Las Campanas Observatory, Chile. These images revealed a second epoch of activity associated with the UT 2023 April 22 perihelion passage of 2009 DQ118. We performed photometric analysis of the tail and find that it had a similar apparent length and surface brightness during both epochs. We also explored the orbital history and future of 2009 DQ118 through dynamical simulations. These simulations show that 2009 DQ118 is currently a quasi-Hilda and that it frequently experiences close encounters with Jupiter. We find that 2009 DQ118 is currently on the boundary between asteroidal and cometary orbits. Additionally, it has likely been a Jupiter family comet or Centaur for much of the past 10 kyr and will be in these same regions for the majority of the next 10 kyr. Since both detected epochs of activity occurred near perihelion, the observed activity is consistent with sublimation of volatile ices. 2009 DQ118 is currently observable until ~mid-October 2023. Further observations would help to characterize the observed activity.

Keywords: Comet tails, Comet dynamics, Hilda group, Asteroid dynamics
Size and Albedo Constraints for (152830) Dinkinesh Using WISE Data. Probing small main-belt asteroids provides insight into their formation and evolution through multiple dynamical and collisional processes. These asteroids also overlap in size with the potentially hazardous near-Earth object population and supply the majority of these objects. The Lucy mission will perform a flyby of the small main-belt asteroid, (152830) Dinkinesh, on 2023 November 1, in preparation for its mission to the Jupiter Trojan asteroids. In this Letter, we present data to support the planning of Lucy's imminent encounter of Dinkinesh. We employed aperture photometry on stacked frames of Dinkinesh obtained by the Wide-field Infrared Survey Explorer and performed thermal modeling on a detection at 12 μm to compute diameter and albedo values. Through this method, we determined Dinkinesh has an effective spherical diameter of ${0.76}_{-0.21}^{+0.11}$ km and a visual geometric albedo of ${0.27}_{-0.06}^{+0.25}$ at the 16th and 84th percentiles. This albedo is consistent with typical stony (S-type) asteroids. These measurements will enable the Lucy team to optimize planning for the flyby of Dinkinesh, including refinement of exposure times and flyby geometry. The data obtained from this mission will, in turn, allow us to better understand the calibration of our thermal models by providing ground truth data. The Lucy flyby presents a rare opportunity to study the smallest main-belt asteroid ever observed in situ.

Keywords: Main belt asteroids, Asteroids
JWST CEERS and JADES Active Galaxies at z = 4-7 Violate the Local M <SUB>•</SUB>-M <SUB>⋆</SUB> Relation at &gt;3σ: Implications for Low-mass Black Holes and Seeding Models. JWST is revolutionizing our understanding of the high-z Universe by expanding the black hole horizon, looking farther and to smaller masses, and revealing the stellar light of their hosts. By examining JWST galaxies at z = 4-7 that host Hα-detected black holes, we investigate (i) the high-z M •-M ⋆ relation and (ii) the black hole mass distribution, especially in its low-mass range (M • ≲ 106.5 M ⊙). With a detailed statistical analysis, our findings conclusively reveal a high-z M •-M ⋆ relation that deviates at &gt;3σ confidence level from the local relation. The high-z relation is $\mathrm{log}({M}_{\bullet }/\,{M}_{\odot })=-{2.43}_{-0.83}^{+0.83}+{1.06}_{-0.09}^{+0.09}\mathrm{log}({M}_{\star }/\,{M}_{\odot })$ . Black holes are overmassive by ~10-100× compared to their low-z counterparts in galactic hosts of the same stellar mass. This fact is not due to a selection effect in surveys. Moreover, our analysis predicts the possibility of detecting in high-z JWST surveys 5-15× more black holes with M • ≲ 106.5 M ⊙, and 10-30× more with M • ≲ 108.5 M ⊙, compared to local relation's predictions. The lighter black holes preferentially occupy galaxies with a stellar mass of ~107.5-108 M ⊙. We have yet to detect these sources because (i) they may be inactive (duty cycles 1%-10%), (ii) the host overshines the active galactic nucleus (AGN), or (iii) the AGN is obscured and not immediately recognizable by line diagnostics. A search of low-mass black holes in existing JWST surveys will further test the M •-M ⋆ relation. Current JWST fields represent a treasure trove of black hole systems at z = 4-7; their detection will provide crucial insights into their early evolution and coevolution with their galactic hosts.

Keywords: Supermassive black holes, Early universe, Surveys, Active galaxies, Galaxy evolution
Discovery of A Large-scale Bent Radio Jet in the Merging Cluster A514. We report a discovery of a large-scale bent radio jet in the merging galaxy cluster A514 (z = 0.071). The radio emission originates from the two radio lobes of the active galactic nucleus (AGN) located near the center of the southern subcluster and extends toward the southern outskirts with multiple bends. Its peculiar morphology is characterized by a 400 kpc "bridge," a 300 kpc "arc," and a 400 kpc "tail," which together contribute to its largest linear size of ~0.7 Mpc. We find that both the flux and spectral features of the emission change with the distance from the AGN. Also, the "bridge" presents a 60% polarized radio emission, which coincided with an X-ray cold front. Based on our multiwavelength observations, we propose that A514 presents a clear case for the redistribution of an old AGN plasma due to merger-driven gas motions. We support our interpretation with idealized cluster merger simulations employing a passive tracer field to represent cosmic-ray electrons and find that merger-driven motions can efficiently create a cloud of these particles in the cluster outskirts, which later can be reaccelerated by the cluster merger shock and produce radio relics.

Keywords: Galaxy clusters, Abell clusters, Radio jets
Pavo: Discovery of a Star-forming Dwarf Galaxy Just Outside the Local Group. We report the discovery of Pavo, a faint (M  V  = -10.0), star-forming, irregular, and extremely isolated dwarf galaxy at D ≈ 2 Mpc. Pavo was identified in Dark Energy Camera Legacy Survey imaging via a novel approach that combines low surface brightness galaxy search algorithms and machine-learning candidate classifications. Follow-up imaging with the Inamori-Magellan Areal Camera and Spectrograph on the 6.5 m Magellan Baade telescope revealed a color-magnitude diagram (CMD) with an old stellar population, in addition to the young population that dominates the integrated light, and a tip of the red giant branch distance estimate of ${1.99}_{-0.22}^{+0.20}$ Mpc. The blue population of stars in the CMD is consistent with the youngest stars having formed no later than 150 Myr ago. We also detected no Hα emission with SOAR telescope imaging, suggesting that we may be witnessing a temporary low in Pavo's star formation. We estimate the total stellar mass of Pavo to be $\mathrm{log}{M}_{* }/{M}_{\odot }=5.6\pm 0.2$ and measure an upper limit on its H I gas mass of 1.0 × 106 M ⊙ based on the HIPASS survey. Given these properties, Pavo's closest analog is Leo P (D = 1.6 Mpc), previously the only known isolated, star-forming, Local Volume dwarf galaxy in this mass range. However, Pavo appears to be even more isolated, with no other known galaxy residing within over 600 kpc. As surveys and search techniques continue to improve, we anticipate an entire population of analogous objects being detected just outside the Local Group. * This paper includes data gathered with the 6.5 m Magellan Telescope at Las Campanas Observatory, Chile.

Keywords: Dwarf irregular galaxies, Galaxy distances, Galaxy environments, Galaxy stellar content, Low surface brightness galaxies
Decomposing the Origin of TeV-PeV Emission from the Galactic Plane: Implications of Multimessenger Observations. High-energy neutrino and γ-ray emission has been observed from the Galactic plane, which may come from individual sources and/or diffuse cosmic rays. We evaluate the contribution of these two components through the multimessenger connection between neutrinos and γ-rays in hadronic interactions. We derive maximum fluxes of neutrino emission from the Galactic plane using γ-ray catalogs, including 4FGL, HGPS, 3HWC, and 1LHAASO, and measurements of the Galactic diffuse emission by Tibet ASγ and LHAASO. We find that the IceCube Galactic neutrino flux is larger than the contribution from all resolved sources when excluding promising leptonic sources such as pulsars, pulsar wind nebulae, and TeV halos. Our result indicates that the Galactic neutrino emission is likely dominated by the diffuse emission by the cosmic-ray sea and unresolved hadronic γ-ray sources. In addition, the IceCube flux is comparable to the sum of the flux of nonpulsar sources and the LHAASO diffuse emission especially above ~30 TeV. This implies that the LHAASO diffuse emission may dominantly originate from hadronic interactions, either as the truly diffuse emission or unresolved hadronic emitters. Future observations of neutrino telescopes and air-shower γ-ray experiments in the Southern hemisphere are needed to accurately disentangle the source and diffuse emission of the Milky Way.

Keywords: Neutrino astronomy, High-energy cosmic radiation
UNCOVER: A NIRSpec Identification of a Broad-line AGN at z = 8.50. Deep observations with the James Webb Space Telescope (JWST) have revealed an emerging population of red pointlike sources that could provide a link between the postulated supermassive black hole seeds and observed quasars. In this work, we present a JWST/NIRSpec spectrum from the JWST Cycle 1 UNCOVER Treasury survey of a massive accreting black hole at z = 8.50 displaying a clear broad-line component as inferred from the Hβ line with FWHM = 3439 ± 413 km s-1, typical of the broad-line region of an active galactic nucleus (AGN). The AGN nature of this object is further supported by high ionization, as inferred from emission lines, and a point-source morphology. We compute a black hole mass of ${\mathrm{log}}_{10}({M}_{\mathrm{BH}}/{M}_{\odot })=8.17\pm 0.42$ and a bolometric luminosity of L bol ~ 6.6 × 1045 erg s-1. These values imply that our object is accreting at ~40% of the Eddington limit. Detailed modeling of the spectral energy distribution in the optical and near-infrared, together with constraints from ALMA, indicate an upper limit on the stellar mass of ${\mathrm{log}}_{10}({M}_{* }/{M}_{\odot })\lt 8.7$ , which would lead to an unprecedented ratio of black hole to host mass of at least ~30%. This is orders of magnitude higher compared to the local QSOs but consistent with recent AGN studies at high redshift with JWST. This finding suggests that a nonnegligible fraction of supermassive black holes either started out from massive seeds and/or grew at a super-Eddington rate at high redshift. Given the predicted number densities of high-z faint AGN, future NIRSpec observations of larger samples will allow us to further investigate galaxy-black hole coevolution in the early Universe.

Keywords: Early universe, Active galactic nuclei, High-redshift galaxies
Deep Synoptic Array Science: Implications of Faraday Rotation Measures of Fast Radio Bursts Localized to Host Galaxies. Faraday rotation measures (RMs) of fast radio bursts (FRBs) offer the prospect of directly measuring extragalactic magnetic fields. We present an analysis of the RMs of 10 as yet nonrepeating FRBs detected and localized to host galaxies with robust redshift measurements by the 63-antenna prototype of the Deep Synoptic Array (DSA-110). We combine this sample with published RMs of 15 localized FRBs, nine of which are repeating sources. For each FRB in the combined sample, we estimate the host-galaxy dispersion measure (DM) contributions and extragalactic RM. We find compelling evidence that the extragalactic components of FRB RMs are often dominated by contributions from the host-galaxy interstellar medium (ISM). Specifically, we find that both repeating and as yet nonrepeating FRBs show a correlation between the host DM and host RM in the rest frame, and we find an anticorrelation between extragalactic RM (in the observer frame) and redshift for nonrepeaters, as expected if the magnetized plasma is in the host galaxy. Important exceptions to the ISM origin include a dense, magnetized circumburst medium in some repeating FRBs, and the intracluster medium of host or intervening galaxy clusters. We find that the estimated ISM magnetic-field strengths, ${\bar{B}}_{| | }$ , are characteristically ~1-2 μG larger than those inferred from Galactic radio pulsars. This suggests either increased ISM magnetization in FRB hosts in comparison with the Milky Way, or that FRBs preferentially reside in regions of increased magnetic-field strength within their hosts.

Keywords: Neutron stars, Cosmic electrodynamics, Extragalactic magnetic fields, Radio pulsars, Pulsars, Polarimetry, Radio transient sources
A Unified Theory of Jetted Tidal Disruption Events: From Promptly Escaping Relativistic to Delayed Transrelativistic Jets. Only a tiny fraction ~1% of stellar tidal disruption events (TDEs) generate powerful relativistic jets evidenced by luminous hard X-ray and radio emissions. We propose that a key property responsible for both this surprisingly low rate and a variety of other observations is the typically large misalignment ψ between the orbital plane of the star and the spin axis of the supermassive black hole (SMBH). Such misaligned disk/jet systems undergo Lense-Thirring precession together about the SMBH spin axis. We find that TDE disks precess sufficiently rapidly that winds from the accretion disk will encase the system on large scales in a quasi-spherical outflow. We derive the critical jet efficiency η &gt; η crit for both aligned and misaligned precessing jets to successfully escape from the disk wind ejecta. As η crit is higher for precessing jets, less powerful jets only escape after alignment with the SMBH spin. Alignment can occur through magneto-spin or hydrodynamic mechanisms, which we estimate occur on typical timescales of weeks and years, respectively. The dominant mechanism depends on η and the orbital penetration factor β. Hence, depending only on the intrinsic parameters of the event {ψ, η, β}, we propose that each TDE jet can either escape prior to alignment, thus exhibiting an erratic X-ray light curve and two-component radio afterglow (e.g., Swift J1644+57), or escape after alignment. Relatively rapid magneto-spin alignments produce relativistic jets exhibiting X-ray power-law decay and bright afterglows (e.g., AT2022cmc), while long hydrodynamic alignments give rise to late jet escape and delayed radio flares (e.g., AT2018hyz).

Keywords: Black hole physics, Tidal disruption, Jets
First Metis Detection of the Helium D<SUB>3</SUB> Line Polarization in a Large Eruptive Prominence. Metis on board Solar Orbiter is the space coronagraph developed by an Italian-German-Czech consortium. It is capable of observing solar corona and various coronal structures in the visible-light (VL) and UV (hydrogen Lyα) channels simultaneously for the first time. Here we present observations of a large eruptive prominence on 2021 April 25-26, in the VL, taken during the mission cruise phase, and demonstrate that apart from the broadband continuum emission, which is due to the Thomson scattering on prominence electrons, we detect a significant radiation in the neutral-helium D3 line (587.6 nm), which lies within the Metis VL passband. We show how the prominence looks like in Stokes I, Q, and U. We consider two extreme cases of the prominence magnetic field, and we separate the Stokes I and Q signals pertinent to Thomson scattering and to the D3 line. The degree of linear polarization of the D3 line (both Q and U) indicates the presence of the prominence magnetic field; hence Metis can serve as a magnetograph for eruptive prominences located high in the corona.

Keywords: Coronagraphic imaging, Solar coronal mass ejections, Solar prominences, Solar corona
Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability. We study the optical flux and polarization variability of the binary black hole blazar OJ 287 using quasi-simultaneous observations from 2015 to 2023 carried out using telescopes in the USA, Japan, Russia, Crimea, and Bulgaria. This is one of the most extensive quasi-simultaneous optical flux and polarization variability studies of OJ 287. OJ 287 showed large amplitude, ~3.0 mag flux variability, large changes of ~37% in degree of polarization, and a large swing of ~215° in the angle of the electric vector of polarization. During the period of observation, several flares in flux were detected. Those flares are correlated with a rapid increase in the degree of polarization and swings in electric vector of polarization angle. A peculiar behavior of anticorrelation between flux and polarization degree, accompanied by a nearly constant polarization angle, was detected from JD 2,458,156 to JD 2,458,292. We briefly discuss some explanations for the flux and polarization variations observed in OJ 287.

Keywords: Jets, BL Lacertae objects, Optical astronomy, Blazars, Active galactic nuclei
Kinematical Fluctuations Vary with Galaxy Surface Mass Density. The Galaxy inner parts are generally considered to be optically symmetric, as well as kinematically symmetric for most massive early-type galaxies. At the lower-mass end, many galaxies contain lots of small patches in their velocity maps, causing their kinematics to be nonsmooth in small scales and far from symmetry. These small patches can easily be mistaken for measurement uncertainties and have not been well discussed. We used the comparison of observations and numerical simulations to demonstrate the small patches existence beyond uncertainties. For the first time we have found that the fluctuation degrees have an approximate inverse loglinear relation with the galaxy stellar surface mass densities. This tight relation among galaxies that do not show obvious optical asymmetry that traces environmental perturbations indicates that stellar motion in galaxies has inherent asymmetry besides external environment influences. The degree of the kinetic asymmetry is closely related to and constrained by the intrinsic properties of the host galaxy.

Keywords: Galaxy structure, Galaxy dynamics, Galaxy kinematics, Dark matter
Irregular Proton Injection to High Energies at Interplanetary Shocks. How thermal particles are accelerated to suprathermal energies is an unsolved issue, crucial for many astrophysical systems. We report novel observations of irregular, dispersive enhancements of the suprathermal particle population upstream of a high-Mach-number interplanetary shock. We interpret the observed behavior as irregular "injections" of suprathermal particles resulting from shock front irregularities. Our findings, directly compared to self-consistent simulation results, provide important insights for the study of remote astrophysical systems where shock structuring is often neglected.

Keywords: Space plasmas, Interplanetary shocks, Heliosphere, Interplanetary particle acceleration, Shocks