Sazuna/UAT_keywords huggingface dataset:
A Low-inclination Neutral Trans-Neptunian Object in an Extreme Orbit. We present photometric observations and numerical simulations of 2016 SD106, a low-inclination (i = 4.°8) extreme trans-Neptunian Object with a large semimajor axis (a = 350 au) and perihelion (q = 42.6 au). This object possesses a peculiar neutral color of g - r = 0.45 ± 0.05 and g - i = 0.72 ± 0.06, in comparison with other distant trans-Neptunian objects, all of which have moderate-red to ultra-red colors. A numerical integration based on orbital fitting on astrometric data covering eight years of arc confirms that 2016 SD106 is a metastable object without significant scattering evolution. Each of the clones survived at the end of the 1 Gyr simulation. However, very few neutral objects with inclinations &lt;5° have been found in the outer solar system, even in the main Kuiper Belt. Furthermore, most mechanisms that lift perihelion distances are expected to produce a very low number of extreme objects with inclinations &lt;5°. We thus explored the possibility that a hypothetical distant planet could increase the production of such objects. Our simulations show that no 2016 SD106-like orbits can be produced from three Kuiper Belt populations tested (i.e., plutinos, twotinos, and the Haumea Family) without the presence of a hypothetical planet, while a few similar orbits can be obtained with it; however, the presence of the additional planet produces a wide range of large semimajor-axis/large perihelion objects, in apparent contradiction with the observed scarcity of objects in those regions of phase space. Future studies may determine if there is a connection between the existence of a perihelion gap and a particular orbital configuration of a hypothetical distant planet.

Keywords: Surveys, Celestial mechanics, Detached objects, Trans-Neptunian objects
Sodium Distribution on the Moon. The Moon is significantly depleted in volatile elements when compared to Earth, an observation that has resulted in various formation scenarios leading to the loss of volatiles. Sodium is a moderately volatile element that is a lithophile, which can be utilized as a tracer of the volatile history in planetary bodies. It is also well observed in the exosphere of several bodies in our solar system and exoplanetary systems. But lunar surface sodium abundances have so far been measured only in samples brought back to Earth. We report on results from the first effort to provide a global-scale measurement of sodium on the lunar surface using X-ray fluorescent spectra from Chandrayaan-2. A global average of 1.33 ± 0.03 wt% derived here is higher than previously known. Trends in the sodium abundance indicate a long-lived adsorbate component that could explain the higher abundances reported here, which would act as a reservoir that sustains the lunar sodium exosphere.

Keywords: Lunar surface, Surface composition, Spectroscopy, Exosphere
Systematic Errors as a Source of Mass Discrepancy in Black Hole Microlensing Event OGLE-2011-BLG-0462. Two independent groups reported the discovery of an isolated dark stellar remnant in the microlensing event OGLE-2011-BLG-0462 based on photometric ground-based observations coupled with astrometric measurements taken with the Hubble Space Telescope. These two analyses yielded discrepant mass measurements, with the first group reporting that the lensing object is a black hole of 7.1 ± 1.3 M ⊙ whereas the other concluded that the microlensing event was caused by either a neutron star or a low-mass black hole (1.6-4.4 M ⊙). Here, we scrutinize the available photometric and astrometric data and conclude that systematic errors are a cause of the discrepant measurements. We find that the lens is an isolated black hole with a mass of 7.88 ± 0.82 M ⊙ located at a distance of 1.49 ± 0.12 kpc. We also study the impact of blending on the accuracy of astrometric microlensing measurements. We find that low-level blending by source companions is a major, previously unrecognized, challenge to astrometric microlensing measurements of black hole masses.

Keywords: Black holes, Astrometric microlensing effect, Gravitational microlensing, Stellar remnants, Astrophysical black holes
Influence of Fine Structures on Gyrosynchrotron Emission of Flare Loops Modulated by Sausage Modes. Sausage modes are a leading mechanism for interpreting short-period quasi-periodic pulsations (QPPs) of solar flares. Forward modeling their radio emission is crucial for identifying sausage modes observationally and for understanding their connections with QPPs. Using the numerical outputs from three-dimensional magnetohydrodynamic simulations, we forward model the gyrosynchrotron emission of flare loops modulated by sausage modes and examine the influence of fine structures of loops. The temporal evolution of the emission intensity is analyzed for an oblique line of sight crossing the loop center. We find that the low- and high-frequency intensities oscillate in phase in the periods of sausage modes for models with or without fine structures. For low-frequency emissions where the optically thick regime arises, the modulation magnitude of the intensity is dramatically reduced by the fine structures at some viewing angles. On the contrary, for high-frequency emissions where the optically thin regime holds, the effects of fine structures or the viewing angle are marginal. Our results show that the periodic intensity variations of sausage modes are not wiped out by fine structures, and that sausage modes remain a promising candidate mechanism for QPPs, even when the flare loops are fine-structured.

Keywords: Solar coronal radio emission, Solar corona, Magnetohydrodynamical simulations
Analysis and Modeling of High-frequency Emission and Deep Seismic Sources of Sunquakes. Recent work published by Lindsey et al. find evidence for a deep and compact seismic source for the sunquake associated with the 2011 July 30 M9.3 flare, as well as seismic emission extending up to 10 mHz. We examine the sunquake independently, and a possible wave front is found in the 8 mHz band, though no wave front is easily discernible in the 10 mHz band. Additionally, we perform numerical simulations of seismic excitation modeled with the reported parameters and changes in the power spectra with increasing depth of the excitation source are examined. It is found that the peak frequency decreases for increasing depths, but a shallow minimum is indicated between z = 0 and z = -840 km. Analysis of the suspected wave front of the M9.3 sunquake finds that the power spectrum of the reported seismic emission is close to that of background oscillations, though with a peak frequency noticeably lower than the background peak. Additionally, it is found that the amplitude of the source estimated by Lindsey et al. is too low to produce the observed wave front.

Keywords: Helioseismology
Toward a Precision Measurement of Binary Black Holes Formation Channels Using Gravitational Waves and Emission Lines. The formation of compact objects-neutron stars, black holes, and supermassive black holes-and their connection to the chemical composition of galaxies is one of the central questions in astrophysics. We propose a novel data-driven, multi-messenger technique to address this question by exploiting the inevitable correlation between gravitational waves and atomic/molecular emission-line signals. For a fiducial probability distribution function $p({t}_{d})\propto {t}_{d}^{-\kappa }$ of time delays, this method can provide a measurement of the minimum delay time of 0.5 Gyr and a power-law index of κ = 1 with a standard deviation of 0.12 (and 0.45) and 0.06 (and 0.34), respectively, from five years of LIGO-Virgo-KAGRA observations in synergy with SPHEREx line intensity mapping (and DESI emission-line galaxies). Such measurements will provide data-driven, multi-messenger constraints on the delay time distribution which is currently not well known.

Keywords: Gravitational waves, Emission line galaxies, Black holes
Dynamical Unification of Tidal Disruption Events. The ~100 tidal disruption events (TDEs) observed so far exhibit a wide range of emission properties both at peak and over their lifetimes. Some TDEs radiate predominantly at X-ray energies, while others radiate chiefly at UV and optical wavelengths. While the peak luminosities across TDEs show distinct properties, the evolutionary behavior can also vary between TDEs with similar peak emission properties. In particular, for optical TDEs, while their UV and optical emissions decline somewhat following the fallback pattern, some events can greatly rebrighten in X-rays at late time. In this Letter, we conduct three-dimensional general relativistic radiation magnetohydrodynamics simulations of TDE accretion disks at varying accretion rates in the regime of super-Eddington accretion. We make use of Monte Carlo radiative transfer simulations to calculate the reprocessed spectra at various inclinations and at different evolutionary stages. We confirm the unified model proposed by Dai et al., which predicts that the observed emission largely depends on the viewing angle of the observer with respect to the disk orientation. Furthermore, we find that disks with higher accretion rates have elevated wind and disk densities, which increases the reprocessing of the high-energy radiation and thus generally augments the optical-to-X-ray flux ratio along a particular viewing angle. This implies that at later times, as the accretion level declines, we expect that more X-rays will leak out along intermediate viewing angles. Such dynamical model for TDEs can provide a natural explanation for the diversity in the emission properties observed in TDEs at peak and along their temporal evolution.

Keywords: Accretion, Black hole physics, Magnetohydrodynamics, Quasars, Radiative transfer, Astrophysical black holes
Modeling of Joint Parker Solar Probe-Metis/Solar Orbiter Observations. We present the first theoretical modeling of joint Parker Solar Probe (PSP)-Metis/Solar Orbiter (SolO) quadrature observations. The combined observations describe the evolution of a slow solar wind plasma parcel from the extended solar corona (3.5-6.3 R ⊙) to the very inner heliosphere (23.2 R ⊙). The Metis/SolO instrument remotely measures the solar wind speed finding a range from 96 to 201 km s-1, and PSP measures the solar wind plasma in situ, observing a radial speed of 219.34 km s-1. We find theoretically and observationally that the solar wind speed accelerates rapidly within 3.3-4 R ⊙ and then increases more gradually with distance. Similarly, we find that the theoretical solar wind density is consistent with the remotely and in-situ observed solar wind density. The normalized cross helicity and normalized residual energy observed by PSP are 0.96 and -0.07, respectively, indicating that the slow solar wind is very Alfvénic. The theoretical NI/slab results are very similar to PSP measurements, which is a consequence of the highly magnetic field-aligned radial flow ensuring that PSP can measure slab fluctuations and not 2D ones. Finally, we calculate the theoretical 2D and slab turbulence pressure, finding that the theoretical slab pressure is very similar to that observed by PSP.

Keywords: Interplanetary turbulence, The Sun, Solar wind
Accelerating Early Massive Galaxy Formation with Primordial Black Holes. Recent observations with JWST have identified several bright galaxy candidates at z ≳ 10, some of which appear unusually massive (up to ~1011 M ⊙). Such early formation of massive galaxies is difficult to reconcile with standard ΛCDM predictions, demanding a very high star formation efficiency (SFE), possibly even in excess of the cosmic baryon mass budget in collapsed structures. With an idealized analysis based on linear perturbation theory and the Press-Schechter formalism, we show that the observed massive galaxy candidates can be explained with lower SFE than required in ΛCDM if structure formation is accelerated/seeded by massive (≳109 M ⊙) primordial black holes (PBHs) that make a up a small fraction (~10-6-10-3) of dark matter, considering existing empirical constraints on PBH parameters. We also discuss the potential observational signatures of PBH cosmologies in the JWST era. More work needs to be done to fully evaluate the viability of such PBH models to explain observations of the high-z Universe.

Keywords: Galaxy abundances, Dark matter, Primordial black holes
A Challenge to the Standard Cosmological Model. We present the first joint analysis of catalogs of radio galaxies and quasars to determine whether their sky distribution is consistent with the standard ΛCDM model of cosmology. This model is based on the cosmological principle, which asserts that the universe is statistically isotropic and homogeneous on large scales, so the observed dipole anisotropy in the cosmic microwave background (CMB) must be attributed to our local peculiar motion. We test the null hypothesis that there is a dipole anisotropy in the sky distribution of radio galaxies and quasars consistent with the motion inferred from the CMB, as is expected for cosmologically distant sources. Our two samples, constructed respectively from the NRAO VLA Sky Survey and the Wide-field Infrared Survey Explorer, are systematically independent and have no shared objects. Using a completely general statistic that accounts for correlation between the found dipole amplitude and its directional offset from the CMB dipole, the null hypothesis is independently rejected by the radio galaxy and quasar samples with p-values of 8.9 × 10-3 and 1.2 × 10-5, respectively, corresponding to 2.6σ and 4.4σ significance. The joint significance, using sample-size-weighted Z-scores, is 5.1σ. We show that the radio galaxy and quasar dipoles are consistent with each other and find no evidence for any frequency dependence of the amplitude. The consistency of the two dipoles improves if we boost to the CMB frame assuming its dipole to be fully kinematic, suggesting that cosmologically distant radio galaxies and quasars may have an intrinsic anisotropy in this frame.

Keywords: Cosmology, Large-scale structure of the universe, Quasars, Observational cosmology, Cosmic microwave background radiation, Infrared astronomy, Radio galaxies, Active galactic nuclei, Radio astronomy
Rest-frame Near-infrared Sizes of Galaxies at Cosmic Noon: Objects in JWST's Mirror Are Smaller than They Appeared. Galaxy sizes and their evolution over cosmic time have been studied for decades and serve as key tests of galaxy formation models. However, at z ≳ 1 these studies have been limited by a lack of deep, high-resolution rest-frame infrared imaging that accurately traces stellar mass distributions. Here, we leverage the new capabilities of the James Webb Space Telescope (JWST) to measure the 4.4 μm sizes of ~1000 galaxies with $\mathrm{log}{M}_{* }/{M}_{\odot }\geqslant 9$ and 1.0 ≤ z ≤ 2.5 from public CEERS imaging in the Extended Groth Strip deep field. We compare the sizes of galaxies measured from NIRCam imaging at 4.4 μm (λ rest ~ 1.6 μm) with sizes measured at 1.5 μm (λ rest ~ 5500 Å). We find that, on average, galaxy half-light radii are ~9% smaller at 4.4 μm than 1.5 μm in this sample. This size difference is markedly stronger at higher stellar masses and redder rest-frame V - J colors: galaxies with M * ~ 1011 M ⊙ have 4.4 μm sizes that are ~30% smaller than their 1.5 μm sizes. Our results indicate that galaxy mass profiles are significantly more compact than their rest-frame optical light profiles at cosmic noon, and demonstrate that spatial variations in age and attenuation are important, particularly for massive galaxies. The trend we find here impacts our understanding of the size growth and evolution of galaxies, and suggests that previous studies based on rest-frame optical light may not have captured the mass-weighted structural evolution of galaxies. This paper represents a first step toward a new understanding of the morphologies of early massive galaxies enabled by JWST's infrared window into the distant universe.

Keywords: Galaxy formation, Galaxy evolution, Galaxy radii
Magnetic Reconnection in Black Hole Magnetospheres: Lepton Loading into Jets, Superluminal Radio Blobs, and Multiwavelength Flares. Supermassive black holes in active galactic nuclei launch relativistic jets, as indicated by observed superluminal radio blobs. The energy source of these jets is widely discussed in the theoretical framework of the Blandford-Znajek process, the electromagnetic energy extraction from rotating black holes (BHs), while the formation mechanism of the radio blobs in the electromagnetically dominated jets has been a long-standing problem. Recent high-resolution magnetohydrodynamic simulations of magnetically arrested disks exhibited magnetic reconnection in a transient magnetically dominated part of the equatorial disk near the BH horizon, which led to a promising scenario of efficient MeV gamma-ray production and subsequent electron-positron pair loading into the BH magnetosphere. We develop this scenario to build a theoretical framework on energetics, timescales, and particle number density of the superluminal radio blobs and discuss observable signatures in other wave bands. We analytically show that the nonthermal electrons emit broadband photons from optical to multi-MeV bands. The electron-positron pairs produced in the magnetosphere are optically thick for synchrotron self-absorption, so that the injected energy is stored in the plasma. The stored energy is enough to power the superluminal radio blobs observed in M87. This scenario predicts rather dim radio blobs around Sgr A*, which are consistent with no clear detection by current facilities. In addition, this scenario inevitably produces strong X-ray flares in a short timescale, which will be detectable by future X-ray satellites.

Keywords: Relativistic jets, Low-luminosity active galactic nuclei, Non-thermal radiation sources, Radio active galactic nuclei, Gamma-rays
The Sparkler: Evolved High-redshift Globular Cluster Candidates Captured by JWST. Using data from JWST, we analyse the compact sources ("sparkles") located around a remarkable z spec = 1.378 galaxy (the 'Sparkler) that is strongly gravitationally lensed by the z = 0.39 galaxy cluster SMACS J0723.3-7327. Several of these compact sources can be cross-identified in multiple images, making it clear that they are associated with the host galaxy. Combining data from JWSTs Near-Infrared Camera (NIRCam) with archival data from the Hubble Space Telescope (HST), we perform 0.4-4.4 μm photometry on these objects, finding several of them to be very red and consistent with the colors of quenched, old stellar systems. Morphological fits confirm that these red sources are spatially unresolved even in the strongly magnified JWST/NIRCam images, while the JWST/NIRISS spectra show [OIII] λ5007 emission in the body of the Sparkler but no indication of star formation in the red compact sparkles. The most natural interpretation of these compact red companions to the Sparkler is that they are evolved globular clusters seen at z = 1.378. Applying DENSE BASIS spectral energy distribution fitting to the sample, we infer formation redshifts of z  form  ~ 7-11 for these globular cluster candidates, corresponding to ages of ~3.9-4.1 Gyr at the epoch of observation and a formation time just ~0.5 Gyr after the Big Bang. If confirmed with additional spectroscopy, these red, compact sparkles represent the first evolved globular clusters found at high redshift, which could be among the earliest observed objects to have quenched their star formation in the universe, and may open a new window into understanding globular cluster formation. Data and code to reproduce our results will be made available at http://canucs-jwst.com/sparkler.html.

Keywords: Globular star clusters, Galaxy clusters, James Webb Space Telescope, Gravitational lensing, Galaxy evolution
Formation of Moons and Equatorial Ridge around Top-shaped Asteroids after Surface Landslide. Top-shaped asteroids have been observed among near-Earth asteroids. About half of them are reported to have moons (on the order of ~1 wt.% of the top-shaped primary) and many of them have an equatorial ridge. A recent study has shown that the enigmatic top-shaped figure of asteroids (e.g., Ryugu, Bennu, and Didymos) could result from an axisymmetric landslide of the primary during a fast spin-up near the breakup rotation period. Such a landslide would inevitably form a particulate disk around an asteroid with a short timescale (~3 hr). However, the long-term full dynamical evolution is not investigated. Here, we perform a continuous simulation (~700 hr) that investigates the sequence of events from the surface landslide that forms a top-shaped asteroid and a particulate disk to disk evolution. We show that the disk quickly spreads and produces moons (within ~300 hr). The mass of the formed moon is consistent with what is observed around the top-shaped asteroids. We also demonstrate that an equatorial ridge is naturally formed because a fraction of the disk particles re-accretes selectively onto the equatorial region of the primary. We envision that Ryugu and Bennu could once have an ancient moon that was later lost due to a successive moon's orbital evolution. Alternatively, at a top-shaped asteroid that has a moon, such as Didymos, no significant orbital evolution of the moon has occurred that would result in its loss. Our study would also be qualitatively applicable to any rubble-pile asteroids near the breakup rotation period.

Keywords: Small Solar System bodies, Asteroid satellites, Near-Earth objects, Asteroids
Explanation of Heliospheric Energetic Neutral Atom Fluxes Observed by the Interstellar Boundary Explorer. Interstellar neutral atoms propagating into the heliosphere experience charge exchange with the supersonic solar wind (SW) plasma, generating ions that are picked up by the SW. These pickup ions (PUIs) constitute ~25% of the proton number density by the time they reach the heliospheric termination shock (HTS). Preferential acceleration of PUIs at the HTS leads to a suprathermal, kappa-like PUI distribution in the heliosheath, which may be further heated in the heliosheath by traveling shocks or pressure waves. In this study, we utilize a dynamic, 3D magnetohydrodynamic model of the heliosphere to show that dynamic heating of PUIs at the HTS and in the inner heliosheath (IHS), as well as a background source of energetic neutral atoms (ENAs) from outside the heliopause, can explain the heliospheric ENA signal observed by the Interstellar Boundary Explorer (IBEX) in the Voyager 2 direction. We show that the PUI heating process at the HTS is characterized by a polytropic index larger than 5/3, likely ranging between γ ~ 2.3 and 2.7, depending on the time in solar cycle 24 and SW conditions. The ENA fluxes at energies &gt;1.5 keV show large-scale behavior in time with the solar cycle and SW dynamic pressure, whereas ENAs &lt; 1.5 keV primarily exhibit random-like fluctuations associated with SW transients affecting the IHS. We find that ≲20% of the ENAs observed at ~0.5-6 keV come from other sources, likely from outside the heliopause as secondary ENAs. This study offers the first model replication of the intensity and evolution of IBEX-Hi ENA observations from the outer heliosphere.

Keywords: Heliosphere, Termination shock, Pickup ions, Ion-neutral reactions, Interplanetary particle acceleration, Interstellar medium, Heliosheath