Sazuna/UAT_keywords huggingface dataset:
ALMA 400 pc Imaging of a z = 6.5 Massive Warped Disk Galaxy. We present 0.″075 (≈400 pc) resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations of the [C II] and dust continuum emission from the host galaxy of the z = 6.5406 quasar, P036+03. We find that the emission arises from a thin, rotating disk with an effective radius of 0.″21 (1.1 kpc). The velocity dispersion of the disk is consistent with a constant value of 66.4 ± 1.0 km s-1, yielding a scale height of 80 ± 30 pc. The [C II] velocity field reveals a distortion that we attribute to a warp in the disk. Modeling this warped disk yields an inclination estimate of 40.°4 ± 1.°3 and a rotational velocity of 116 ± 3 km s-1. The resulting dynamical mass estimate of (1.96 ± 0.10) × 1010 M ☉ is lower than previous estimates, which strengthens the conclusion that the host galaxy is less massive than expected based on local scaling relations between the black hole mass and the host galaxy mass. Using archival MUSE Lyα observations, we argue that counterrotating halo gas could provide the torque needed to warp the disk. We further detect a region with excess (15σ) dust continuum emission, which is located 1.3 kpc northwest of the galaxy's center and is gravitationally unstable (Toomre Q &lt; 0.04). We posit this is a star-forming region whose formation was triggered by the warp because the region is located within a part of the warped disk where gas can efficiently lose angular momentum. The combined ALMA and MUSE imaging provides a unique view of how gas interactions within the disk-halo interface can influence the growth of massive galaxies within the first billion years of the Universe.

Keywords: Supermassive black holes, Interstellar atomic gas, Quasars, Disk galaxies, Galaxy dynamics, Galaxy kinematics, Galaxy evolution, Interstellar medium, Circumgalactic medium, Submillimeter astronomy
On the "Loose" Constraint from IceCube Neutrino Nondetection of GRB 230307A. The recent extremely bright gamma-ray burst (GRB) from a binary neutron star merger, GRB 230307A, may offer a good probe for the production of GRB neutrinos. Within the constraint from IceCube neutrino nondetection, the limits for key physical parameters of this burst are extracted in different scenarios, including the fireball, Poynting-flux-dominated, and hybrid jet. Different from the former nearby "monsters" and due to its smaller isotropic equivalent radiated energy (E  γ,iso ~ 4 × 1052 erg), the constraint seems loose if nonthermal neutrinos produced from photomeson interactions are the only consideration. However, a quasi-thermal neutrino emission from hadronuclear processes is constrained in this neutron-rich postmerger environment, and the upper limit of the allowed nucleon loading factor is ~a few. Based on this, a discussion is presented on the possible prompt emission mechanism and jet composition for GRB 230307A in the context of multimessenger astrophysics. It is worth noting that until now, no GRB neutrinos have been ever detected, even for the two brightest nearby GRBs ever observed (GRB 221009A and GRB 230307A), which have different dissipation mechanisms.

Keywords: Neutrino astronomy, Gamma-ray bursts
On the Optical Transients from Double White-dwarf Mergers. Double white dwarf (DWD) mergers are relevant astrophysical sources expected to produce massive, highly magnetized white dwarfs (WDs), supernovae (SNe) Ia, and neutron stars (NSs). Although they are expected to be numerous sources in the sky, their detection has evaded the most advanced transient surveys. This article characterizes the optical transient expected from DWD mergers in which the central remnant is a stable (sub-Chandrasekhar) WD. We show that the expansion and cooling of the merger's dynamical ejecta lead to an optical emission peaking at 1-10 days postmerger, with luminosities of 1040-1041 erg s-1. We present simulations of the light curves, spectra, and the color evolution of the transient. We show that these properties, together with the estimated rate of mergers, are consistent with the absence of detection, e.g., by the Zwicky Transient Facility. More importantly, we show that the Legacy Survey of Space and Time of the Vera C. Rubin Observatory will likely detect a few/several hundred per year, opening a new window to the physics of WDs, NSs, and SNe Ia.

Keywords: Stellar mergers, Visible sources, White dwarf stars, Compact binary stars, Compact objects
The Structure Function of Mid-infrared Variability in Low-redshift Active Galactic Nuclei. Using the multi-epoch mid-infrared (MIR) photometry from the Wide-field Infrared Survey Explorer spanning a baseline of ~10 yr, we extensively investigate the MIR variability of nearby active galactic nuclei (AGNs) at 0.15 &lt; z &lt; 0.4. We find that the ensemble structure function in the W1 band (3.4 μm) can be modeled with a broken power law. Type 1 AGNs tend to exhibit larger variability amplitudes than type 2 AGNs, possibly due to the extinction by the torus. The variability amplitude is inversely correlated with the AGN luminosity, consistent with a similar relation known in the optical. Meanwhile, the slope of the power law increases with AGN luminosity. This trend can be attributed to the fact that the inner radius of the torus is proportional to the AGN luminosity, as expected from the size-luminosity relation of the torus. Interestingly, low-luminosity type 2 AGNs, unlike low-luminosity type 1 AGNs, tend to exhibit smaller variability amplitude than do high-luminosity AGNs. We argue that either low-luminosity type 2 AGNs have distinctive central structures due to their low luminosity or their MIR brightness is contaminated by emission from the cold dust in the host galaxy. Our findings suggest that the AGN unification scheme may need to be revised. We find that the variability amplitude of dust-deficient AGNs is systematically larger than that of normal AGNs, supporting the notion that the hot and warm dust in dust-deficient AGNs may be destroyed and reformed according to the strength of the ultraviolet radiation from the accretion disk.

Keywords: Active galactic nuclei, Quasars
Identifying Physical Structures in Our Galaxy with Gaussian Mixture Models: An Unsupervised Machine Learning Technique. We explore the potential of the Gaussian mixture model (GMM), an unsupervised machine-learning method, to identify coherent physical structures in the interstellar medium. The implementation we present can be used on any kind of spatially and spectrally resolved data set. We provide a step-by-step guide to use these models on different sources and data sets. Following the guide, we run the models on NGC 1977, RCW 120, and RCW 49 using the [C II] 158 μm mapping observations from the SOFIA telescope. We find that the models identified six, four, and five velocity coherent physical structures in NGC 1977, RCW 120, and RCW 49, respectively, which are validated by analyzing the observed spectra toward these structures and by comparison to earlier findings. In this work we demonstrate that GMM is a powerful tool that can better automate the process of spatial and spectral analysis to interpret mapping observations.

Keywords: Star forming regions, Gaussian mixture model
Anisotropic Star Clusters around Recoiling Supermassive Black Holes. Gravitational-wave recoil kicks from merging supermassive black hole binaries can have a profound effect on the surrounding stellar population. In this work, we study the dynamic and kinematic properties of nuclear star clusters following a recoil kick. We show that these postkick structures present unique signatures that can provide key insight to observational searches for recoiling supermassive black holes. In our previous paper, we showed that an in-plane recoil kick turns a circular disk into a lopsided, eccentric disk such as the one we observe in the Andromeda nucleus. Building on this work, here we explore many recoil kick angles as well as initial stellar configurations. For a circular disk of stars, an in-plane kick causes strong apsidal alignment with a significant fraction of the disk becoming retrograde at large radii. If the initial orbits are highly eccentric, an in-plane kick forms a bar-like structure made up of two antialigned lopsided disks. An out-of-plane kick causes clustering in the argument of periapsis, ω, regardless of the initial eccentricity distribution. Initially, isotropic configurations form anisotropies in the form of a torus of eccentric orbits oriented perpendicular to the recoil kick. Postkick surface density and velocity maps are presented in each case to highlight the distinct, observable structures of these systems.

Keywords: Gravitational waves, Stellar dynamics, Galaxy nuclei
The Impact of Angular Momentum Loss on the Outcomes of Binary Mass Transfer. We use the rapid binary population synthesis code COMPAS to investigate commonly used prescriptions for the determination of mass transfer stability in close binaries and the orbital separations after stable mass transfer. The degree of orbital tightening during nonconservative mass transfer episodes is governed by the poorly constrained angular momentum carried away by the ejected material. Increased orbital tightening drives systems toward unstable mass transfer leading to a common envelope. We find that the fraction of interacting binaries that will undergo only stable mass transfer throughout their lives fluctuates between a few and ~20% due to uncertainty in the angular momentum loss alone. If mass transfer is significantly nonconservative, stability prescriptions that rely on the assumption of conservative mass transfer underpredict the number of systems which experience unstable mass transfer and stellar mergers. This may substantially impact predictions about the rates of various transients, including luminous red novae, stripped-envelope supernovae, X-ray binaries, and the progenitors of coalescing compact binaries.

Keywords: Interacting binary stars, Stellar mergers, Common envelope binary stars
Mass and Angular Momentum Transport in a Gravitationally Unstable Protoplanetary Disk with Improved 3D Radiative Hydrodynamics. During early phases of a protoplanetary disk's life, gravitational instabilities (GIs) can produce significant mass transport, can dramatically alter disk structure, can mix and shock-process gas and solids, and may be instrumental in planet formation. We present a 3D grid-based radiative hydrodynamics study with varied resolutions of a 0.07 M ⊙ disk orbiting a 0.5 M ⊙ star as it settles over most of its radial extent into a quasi-steady asymptotic state that maintains approximate balance between heating produced by GIs and radiative cooling governed by realistic dust opacities. We assess disk stability criteria, thermodynamic properties, strengths of GIs, characteristics of density waves and torques produced by GIs, radial mass transport arising from these torques, and the level to which transport can be represented as local or nonlocal processes. Physical and thermal processes display distinct differences between inner optically thick and outer optically thin regions of the disk. In the inner region, gravitational torques are dominated by low-order Fourier components of the azimuthal mass distribution. These torques are strongly variable on the local dynamical time and are subject to rapid flaring presumably driven by recurrent swing amplification. In the outer region, m = 1 torques dominate. Ring-like structures exhibiting strong noncircular motions, and vortices develop near the inner edge between 8 and 14 au. We find that GI-induced spiral modes erupt in a chaotic manner over the whole low-Q part of the disk, with many spiral modes appearing and disappearing, producing gravitoturbulence, but dominated by fluctuating large-scale modes, very different from a simple α-disk.

Keywords: Hydrodynamical simulations, Gravitational instability, Hydrodynamics, Protoplanetary disks, Stellar accretion disks
Disk Cooling and Wind Lines as Seen in the Spectral Line Evolution of V960 Mon. We follow up our photometric study of the postoutburst evolution of the FU Ori object V960 Mon with a complementary spectroscopic study at high dispersion that uses time series spectra from the Keck/HIgh Resolution Echelle Spectrograph. Consistent with the photometric results reported in Carvalho et al., we find that the spectral evolution of V960 Mon corresponds to a decrease in the temperature of the inner disk, driven by a combination of a decreasing accretion rate and an increasing inner disk radius. We also find that although the majority of the absorption lines are well matched by our accretion disk model spectrum, there are several strong absorption line families and a few emission lines that are not captured by the model. By subtracting the accretion disk model from the data at each epoch, we isolate the wind and outflow components of the system. The residuals show both broad and highly blueshifted profiles, as well as narrow and only slightly blueshifted profiles, with some lines displaying both types of features.

Keywords: High resolution spectroscopy, Optical bursts, FU Orionis stars, Stellar winds, Young stellar objects, Stellar accretion disks
Spectral Templates Optimal for Selecting Galaxies at z &gt; 8 with the JWST. The selection of high-redshift galaxies often involves spectral energy distribution (SED) fitting to photometric data, an expectation for contamination levels, and measurement of sample completeness-all vetted through comparison to spectroscopic redshift measurements of a sub-sample. The first JWST data are now being taken over several extragalactic fields to different depths and across various areas, which will be ideal for the discovery and classification of galaxies out to distances previously uncharted. As spectroscopic redshift measurements for sources in this epoch will not be initially available to compare with the first photometric measurements of z &gt; 8 galaxies, robust photometric redshifts are of the utmost importance. Galaxies at z &gt; 8 are expected to have bluer rest-frame ultraviolet (UV) colors than typically used model SED templates, which could lead to catastrophic photometric redshift failures. We use a combination of BPASS and CLOUDY models to create a supporting set of templates that match the predicted rest-UV colors of z &gt; 8 simulated galaxies. We test these new templates by fitting simulated galaxies in a mock catalog, Yung et al., which mimic expected field depths and areas of the JWST Cosmic Evolution Early Release Science Survey (m 5σ  ~ 28.6 over ~100 arcmin2). We use EAZY to highlight the improvements in redshift recovery with the inclusion of our new template set and suggest criteria for selecting galaxies at 8 &lt; z &lt; 10 with the JWST, providing an important test case for observers venturing into this new era of astronomy.

Keywords: Spectral energy distribution, Galaxies, Astronomical simulations
Influence of an Upstream Dynamic Pressure Pulse on Venus-Solar Wind Interaction by Multispecies Magnetohydrodynamic Simulation. As an unmagnetized planet, Venus does not have a global dipole magnetic field like Earth. The solar wind interacts directly with the Venusian ionosphere. In this paper, the interaction between solar wind and the Venusian upper atmosphere is investigated by conducting a three-dimensional multispecies magnetohydrodynamic (MHD) model, in which the Venusian ionosphere is developed self-consistently by considering chemical reactions among four major ion species (H+, O2 +, O+, and CO2 +). Based on this developed MHD model, we mainly study the effects of the impulsive solar wind dynamic pressure on the interaction process. Simulation results reveal that the locations of the bow shock and magnetic pileup boundary show an abrupt compression, then expansion, and finally shrinkage to reach a new steady state with the influence of the impulsive dynamic pressure. The recovery time of the large-scale magnetic field is a few minutes. In addition, the peak escape fluxes are enhanced by about 1 order of magnitude due to the increased solar wind dynamic pressure pulse.

Keywords: Venus
Using a Quench Level Approximation to Estimate the Effect of Metallicity on the Abundances of N-bearing Species in H<SUB>2</SUB>-dominated Atmospheres. Variations in atmospheric elemental nitrogen can considerably affect the abundance of major nitrogen-bearing species such as NH3 and HCN. Also, due to vertical mixing and photochemistry, their abundance deviates from thermochemical equilibrium. The goal of this study is to understand the effect of atmospheric metallicity on the composition of NH3, N2, and HCN over a large parameter space in the presence of vertical mixing, which when combined with the work on CHO-bearing species in Soni &amp; Acharyya can provide a comprehensive understanding of the effect of atmospheric metallicity. We used quenching approximations and a full chemical kinetics model for the calculations, and a comparison between these two methods was made. To generate thermal profiles, the petitRADTRANS code was used. Chemical timescales of NH3 and N2 are found to be complex functions of metallicity, while HCN is inversely proportional. Using quenched abundances of NH3 and CO, the quenched abundance of HCN can be constrained since it remains in equilibrium with NH3, CO, and H2O. Quenched NH3 increases with increasing K  zz  until a particular point, after which it becomes independent of vertical mixing. There is a sweet spot in the K  zz  parameter space to maximize the quenched HCN for a given T int and T equi; the parameter space moves toward a lower equilibrium temperature, and the abundance of HCN increases with metallicity. Finally, we used a data set of quenched abundances to provide a list of potential candidates in which the observation of HCN is possible.

Keywords: Atmospheric composition, Metallicity, Exoplanet atmospheres
Analyses of  0.05-2 MeV Ions Associated with the 2022 February 16 Energetic Storm Particle Event Observed by Parker Solar Probe. We present analyses of 0.05-2 MeV ions from the 2022 February 16 energetic storm particle event observed by Parker Solar Probe's (PSP) IS☉IS/EPI-Lo instrument at 0.35 au from the Sun. This event was characterized by an enhancement in ion fluxes from a quiet background, increasing gradually with time with a nearly flat spectrum, rising sharply near the arrival of the coronal mass ejection (CME)-driven shock, becoming nearly a power-law spectrum, then decaying exponentially afterward, with a rate that was independent of energy. From the observed fluxes, we determine diffusion coefficients, finding that far upstream of the shock the diffusion coefficients are nearly independent of energy, with a value of 1020 cm2 s-1. Near the shock, the diffusion coefficients are more than 1 order of magnitude smaller and increase nearly linearly with energy. We also determine the source of energetic particles, by comparing ratios of the intensities at the shock to estimates of the quiet-time intensity to predictions from diffusive shock acceleration theory. We conclude that the source of energetic ions is mostly the solar wind for this event. We also present potential interpretations of the near-exponential decay of the intensity behind the shock. One possibility we suggest is that the shock was overexpanding when it crossed PSP and the energetic particle intensity decreased behind the shock to fill the expanding volume. Overexpanding CMEs could well be more common closer to the Sun, and this is an example of such a case.

Keywords: Solar energetic particles, Interplanetary particle acceleration, Interplanetary shocks, Solar coronal mass ejections
Unraveling the Complex Structure of AGN-driven Outflows. VI. Strong Ionized Outflows in Type 1 AGNs and the Outflow Size-Luminosity Relation. We present spatially resolved gas kinematics, ionization, and energetics of 11 type 1 and 5 type 2 active galactic nuclei (AGNs) with strong ionized gas outflows at z &lt;0.3 using Gemini Multi-Object Spectrograph Integral Field Unit data. We find a strongly blueshifted region in [O III] velocity maps, representing an approaching cone in biconical outflows, and blueshifted and redshifted regions in Hα velocity maps, which show gravitationally rotating kinematics. AGN photoionization is dominant in the central region of most targets, and some of them also show ring-like structures of LINER or composite that surround the AGN-dominated center. Following our previous studies, we kinematically determine outflow sizes by the ratio between [O III] and stellar velocity dispersion. Outflow sizes of type 1 AGNs follow the same kinematic outflow size-[O III] luminosity relation obtained from the type 2 Integral Field Unit sample in Kang &amp; Woo and Luo (updated slope 0.29 ± 0.04), while they are limited to the central kiloparsec scales, indicating the lack of global impact of outflows on the interstellar medium. Small mass outflow rates and large star formation rates of the combined sample support that there is no evidence of rapid star formation quenching by outflows, which is consistent with the delayed AGN feedback.

Keywords: AGN host galaxies, Star formation, Quasars
Magnetized Accretion Disks with Outflows for Changing-look AGNs. Changing-look active galactic nuclei (CL-AGNs) challenge the standard accretion theory, owing to their rapid variability. Recent numerical simulations have shown that, for the sub-Eddington accretion case, the disk is magnetic pressure-dominated, thermally stable, and geometrically thicker than the standard disk. In addition, outflows were found in the simulations. Observationally, high blueshifted velocities absorption lines indicate that outflows exist in AGNs. In this work, based on the simulation results, we investigate the magnetic pressure-dominated disk, and find that the accretion timescale is significantly shorter than that of the standard thin disk. However, such a timescale is still longer than that of the CL-AGNs. Moreover, if the role of outflows is taken into account, then the accretion timescale can be shortened even further. By the detailed comparison of the theoretical accretion timescale with the observations, we propose that the magnetic pressure-dominated disk incorporating outflows can be responsible for the rapid variability of CL-AGNs.

Keywords: Accretion, Galaxy accretion disks, Active galactic nuclei, Magnetic fields
Gas-phase Metallicity of Local Active Galactic Nuclei in the GASP and MaNGA Surveys: The Role of Ram Pressure Stripping. Growing evidence in support of a connection between active galactic nuclei (AGN) activity and the ram pressure stripping (RPS) phenomenon has been found both observationally and theoretically in the past decades. In this work, we further explore the impact of RPS on the AGN activity by estimating the gas-phase metallicity of nuclear regions and the mass─metallicity relation of galaxies at z ≤ 0.07 and with stellar masses $\mathrm{log}{M}_{* }/{M}_{\odot }\geqslant 9.0$ , either experiencing RPS or not. To measure oxygen abundances, we exploit Integral Field Spectroscopy data from the GASP and MaNGA surveys, photoionization models generated with the code CLOUDY and the code NEBULABAYES to compare models and observations. In particular, we build CLOUDY models to reproduce line ratios induced by photoionization from stars, AGN, or a contribution of both. We find that the distributions of metallicity and [O III] λ5007 luminosity of galaxies undergoing RPS are similar to the ones of undisturbed galaxies. Independently of the RPS, we do not find a correlation between stellar mass and AGN metallicity in the mass range $\mathrm{log}{M}_{* }/{M}_{\odot }\geqslant 10.4$ , while for the star-forming galaxies we observe the well-known mass─metallicity relation between $9.0\leqslant \mathrm{log}\ {M}_{* }/{M}_{\odot }\leqslant 10.8$ with a scatter mainly driven by the star formation rate and a plateau around $\mathrm{log}{M}_{* }/{M}_{\odot }\sim 10.5$ . The gas-phase metallicity in the nuclei of AGN hosts is enhanced with respect to those of star-forming galaxies by a factor of ∼ 0.05 dex regardless of the RPS.

Keywords: Active galactic nuclei, Galaxy chemical evolution, Galaxy environments