Sazuna/UAT_keywords huggingface dataset:
The MAVERIC Survey: New Compact Binaries Revealed by Deep Radio Continuum Observations of the Galactic Globular Cluster Terzan 5. Owing to its massive, dense core, Terzan 5 has the richest population of millisecond pulsars (MSPs) known among Galactic globular clusters. Here we report new deep 2-8 GHz radio continuum observations of Terzan 5 obtained with the Karl G. Jansky Very Large Array. We have identified a total of 24 sources within the cluster half-light radius, including 17 within the core radius. Nineteen are associated with previously studied MSPs and X-ray binaries. Three of the new radio sources have steep radio spectra and are located within the cluster core, as expected for MSPs. These three sources have hard X-ray photon indices (Γ = 1.3-1.5) and highly variable X-ray emission, suggesting they are binary MSPs belonging to the spider class. For the most X-ray luminous of these sources, the redback spider classification is confirmed by its X-ray light curve, which shows an orbital period of 12.32 hr and double-peaked structure around X-ray maximum. The likely discovery of bright binary MSPs in a well-studied cluster like Terzan 5 highlights how deep radio continuum imaging can complement pulsar search and timing observations in finding probable eclipsing systems. The other new radio source in the core has a flat radio spectrum and is X-ray faint ( ${L}_{X}\approx 2\times {10}^{31}$ erg s-1) with a photon index Γ = 2.1 ± 0.5, consistent with the properties expected for a quiescent stellar-mass black hole X-ray binary.

Keywords: Globular star clusters, Millisecond pulsars, Surveys, Radio continuum emission, Catalogs
Predicting the Kinematic Evidence of Gravitational Instability. Observations with the Atacama Large Millimeter/Submillimeter Array (ALMA) have dramatically improved our understanding of the site of exoplanet formation: protoplanetary disks. However, many basic properties of these disks are not well understood. The most fundamental of these is the total disk mass, which sets the mass budget for planet formation. Disks with sufficiently high masses can excite gravitational instability and drive spiral arms that are detectable with ALMA. Although spirals have been detected in ALMA observations of the dust, their association with gravitational instability, and high disk masses, is far from clear. Here we report a prediction for kinematic evidence of gravitational instability. Using hydrodynamics simulations coupled with radiative transfer calculations, we show that a disk undergoing such instability has clear kinematic signatures in molecular line observations across the entire disk azimuth and radius, which are independent of viewing angle. If these signatures are detected, it will provide the clearest evidence for the occurrence of gravitational instability in planet-forming disks, and provide a crucial way to measure disk masses.

Keywords: Protoplanetary disks
Velocity-inverted Three-dimensional Distribution of the Gas Clouds in the Type 2 AGN NGC 1068. Spatially resolved velocity maps at high resolutions of 1-10 pc are becoming available for many nearby active galactic nuclei (AGNs) in both optical/infrared atomic emission lines and submillimeter molecular lines. For the former, it is known that a linear relationship appears to exist between the velocity of the ionized gas clouds and the distance from the nucleus in the inner ∼100 pc region, where these clouds are outflowing. Here we demonstrate that, in such a case, we can actually derive the three-dimensional (3D) geometrical distribution of the clouds directly from the velocity map. Revisiting such a velocity map taken by the Hubble Space Telescope for the prototypical Type 2 AGN NGC 1068, we implement the visualization of the 3D distribution derived from the map, and show that this inner narrow-line region has indeed a hollow-cone structure, consistent with previous modeling results. Quite possibly, this is the outer extended part of the polar elongated dusty material seen in the recent mid-infrared interferometry at parsec scale. Conversely, the latter small-scale geometry is inferred to have a hollow-cone outflowing structure as the inward extension of the derived 3D distribution above. The AGN obscuring "torus" is argued to be the inner optically thick part of this hollow-cone outflow, and its shadowed side would probably be associated with the molecular outflow seen in certain submillimeter lines. We discuss the nature of the linear velocity field, which could be from an episodic acceleration that occurred ∼105 yr ago.

Keywords: Supermassive black holes, Seyfert galaxies, Active galactic nuclei, Interferometry
Supermassive Black Hole Fueling in IllustrisTNG: Impact of Environment. We study the association between active galactic nuclei (AGNs) and environment at scales of 0.01-1 ${h}^{-1}$ Mpc in the IllustrisTNG simulated universe (TNG100). We identify supermassive black hole (BH) pairs and multiples within scales of 0.01, 0.1, and 1 ${h}^{-1}$ Mpc and examine their AGN activity in relation to randomly selected pairs and multiples. The number density of BHs in TNG100 is n = 0.06 h3 Mpc-3 at z ≲ 1.5 (n = 0.02 h3 Mpc-3 at z = 3). About ∼10% and ∼1% of these BHs live in pairs and multiples, respectively, within 0.1 ${h}^{-1}$ Mpc scales. These systems have enhanced likelihood (up to factors of 3-6) of containing high Eddington ratio (η ≳ 0.7) AGNs compared to random pairs and multiples. Conversely, the likelihood of an AGN to live in 0.1 ${h}^{-1}$ Mpc scale BH systems is also higher (by factors ∼4 for η ≳ 0.7) compared to random pairs and multiples. ∼10% of ultra-hard X-ray selected AGNs in TNG100 have detectable 2-10 keV AGN companions on 0.1 ${h}^{-1}$ Mpc scales, consistent with observations. On larger spatial scales (∼1 ${h}^{-1}$ Mpc), however, no significant enhancements in AGN activity exist, even at high Eddington ratios. This implies that small-scale (≲0.1 ${h}^{-1}$ Mpc) AGN enhancement is likely driven by galaxy interactions and mergers. Nonetheless, the overall percentage of AGNs living in ≲0.1 ${h}^{-1}$ Mpc scale multiples is still subdominant (≲40%). Furthermore, the associated Eddington ratio enhancements of BH systems (as well as merging BHs) is only up to factors of ∼2-3. Our results support the existence of merger-AGN connection in TNG100. However, it plays a relatively minor role in fueling the AGN population.

Keywords: Supermassive black holes, Active galactic nuclei
Magnetic Cloud and Sheath in the Ground-level Enhancement Event of 2000 July 14. I. Effects on the Solar Energetic Particles. Ground-level enhancements generally accompany fast interplanetary coronal mass ejections (ICMEs), and ICME-driven shocks are sources of solar energetic particles (SEPs). Observations of the GLE event of 2000 July 14 show that a very fast and strong magnetic cloud (MC) is behind the ICME shock and the proton intensity-time profiles observed at 1 au had a rapid two-step decrease near the sheath and MC. Therefore, we study the effect of sheath and MC on SEPs accelerated by an ICME shock by numerically solving the focused transport equation. The shock is regarded as a moving source of SEPs with an assumed particle distribution function. The sheath and MC are set to thick spherical caps with enhanced magnetic field, and the turbulence levels in the sheath and MC are set to be higher and lower than those of the ambient solar wind, respectively. The simulation results of proton intensity-time profiles agree well with the observations in energies ranging from ∼1 to ∼100 MeV, and the two-step decrease is reproduced when the sheath and MC arrived at the Earth. The simulation results show that the sheath-MC structure reduced the proton intensities for about 2 days after the shock passed through the Earth. It is found that the sheath contributed most of the decrease while the MC facilitated the formation of the second step decrease. The simulation also infers that the coordination of magnetic field and turbulence in sheath-MC structure can produce a stronger reduction of SEP intensities.

Keywords: Solar energetic particles, Space weather, Solar coronal mass ejection shocks, Solar coronal mass ejections, Solar storm, Solar particle emission
Temperature and Metallicity Gradients in the Hot Gas Outflows of M82. We utilize deep Chandra X-ray Observatory imaging and spectra of M82, the prototype of a starbursting galaxy with a multiphase wind, to map the hot plasma properties along the minor axis of the galaxy. We extract spectra from 11 regions up to ±2.5 kpc from the starbursting midplane and model the data as a multitemperature, optically thin thermal plasma with contributions from a nonthermal (power-law) component and from charge exchange (CX). We examine the gradients in best-fit parameters, including the intrinsic column density, plasma temperature, metal abundances, and number density of the hot gas as a function of distance from the M82 nucleus. We find that the temperatures and number densities of the warm-hot and hot plasma peak at the starbursting ridge and decrease along the minor axis. The temperature and density profiles are inconsistent with spherical adiabatic expansion of a super-heated wind and suggest mass loading and mixing of the hot phase with colder material. Nonthermal emission is detected in all of the regions considered, and CX comprises 8%-25% of the total absorption-corrected, broadband (0.5-7 keV) X-ray flux. We show that the abundances of O, Ne, Mg, and Fe are roughly constant across the regions considered, while Si and S peak within 500 pc of the central starburst. These findings support a direct connection between the M82 superwind and the warm-hot, metal-rich circumgalactic medium (CGM).

Keywords: Starburst galaxies, Galactic winds
Lux Ex Tenebris: The Imprint of Annihilating Dark Matter on the Intergalactic Medium during Cosmic Dawn. Upcoming measurements of the highly redshifted 21 cm line with next-generation radio telescopes such as the Hydrogen Epoch of Reionization Array (HERA) and Square Kilometer Array will provide the intriguing opportunity to probe dark matter (DM) physics during the Epoch of Reionization, Cosmic Dawn, and the Dark Ages. With HERA already under construction, there is a pressing need to thoroughly understand the impact of DM physics on the intergalactic medium (IGM) during these epochs. We present first results of a hydrodynamic simulation suite with 2 × 5123 particles in a (100 h-1 Mpc)3 box with DM annihilation and baryonic cooling physics. We focus on redshift z ∼ 11, just before reionization starts in our simulations, and discuss the imprint of DM annihilation on the IGM and on structure formation. We find that whereas structure formation is not affected by thermal weakly interacting massive particles heavier than mχ ≳ 100 MeV, heating from ${ \mathcal O }$ (GeV) DM particles may leave a significant imprint on the IGM that alters the 21 cm signal. Cold gas in low-density regions is particularly susceptible to the effects of DM heating. We note, however, that delayed energy deposition is not currently accounted for in our simulations.

Keywords: Galaxy formation, Reionization, Dark matter, Large-scale structure of the universe
On the Temperature Profiles and Emission Spectra of Mini-Neptune Atmospheres. Atmospheric observations of mini-Neptunes orbiting M dwarfs are beginning to provide constraints on their chemical and thermal properties, while also providing clues about their interiors and potential surfaces. With their relatively large scale heights and large planet-star contrasts, mini-Neptunes are currently ideal targets toward the goal of characterizing temperate low-mass exoplanets. Understanding the thermal structures and spectral appearances of mini-Neptunes is important to understand various aspects of their atmospheres, including radiative/convective energy transport, boundary conditions for the interior, and their potential habitability. In the present study, we explore these aspects of mini-Neptunes using self-consistent models of their atmospheres. We begin by exploring the effects of irradiation, internal flux, metallicity, clouds, and hazes on the atmospheric temperature profiles and thermal emission spectra of temperate mini-Neptunes. In particular, we investigate the impact of these properties on the radiative-convective boundary and the thermodynamic conditions in the lower atmosphere, which serves as the interface with the interior and/or a potential surface. Building on recent suggestions of habitability of the mini-Neptune K2-18 b, we find a range of physically motivated atmospheric conditions that allow for liquid water under the H2-rich atmospheres of such planets. We find that observations of thermal emission with JWST/MIRI spectrophotometry can place useful constraints on the habitability of temperate mini-Neptunes such as K2-18 b and provide more detailed constraints on the chemical and thermal properties of warmer planets such as GJ 3470 b. Our results underpin the potential of temperate mini-Neptunes such as K2-18 b as promising candidates in the search for habitable exoplanets.

Keywords: Exoplanets, Radiative transfer, Spectroscopy, Mini Neptunes, Habitable planets, Exoplanet atmospheres
Constraining the Kilonova Rate with Zwicky Transient Facility Searches Independent of Gravitational Wave and Short Gamma-Ray Burst Triggers. The first binary neutron star merger, GW170817, was accompanied by a radioactivity-powered optical/infrared transient called a kilonova. To date, no compelling kilonova has been found in all-sky optical surveys, independently of short gamma-ray burst and gravitational-wave triggers. In this work, we searched the first 23 months of the Zwicky Transient Facility (ZTF) data stream for candidate kilonovae in the form of rapidly evolving transients. We combined ZTF alert queries with forced point-spread-function photometry and nightly flux stacking to increase our sensitivity to faint and fast transients. Automatic queries yielded &gt;11,200 candidates, 24 of which passed quality checks and selection criteria based on a grid of kilonova models tailored for both binary neutron star and neutron star-black hole mergers. None of the candidates in our sample was deemed a possible kilonova after thorough vetting. The sources that passed our selection criteria are dominated by Galactic cataclysmic variables. We identified two fast transients at high Galactic latitude, one of which is the confirmed afterglow of long-duration GRB 190106A, the other is a possible cosmological afterglow. Using a survey simulation code, we constrained the kilonova rate for a range of models including top-hat, linearly decaying light curves, and synthetic light curves obtained with radiative transfer simulations. For prototypical GW170817-like kilonovae, we constrain the rate to be $R\lt 1775$ Gpc-3 yr-1 (95% confidence). By assuming a population of kilonovae with the same geometry and composition of GW170817 observed under a uniform viewing angle distribution, we obtained a constraint on the rate of R &lt; 4029 Gpc-3 yr-1.

Keywords: Neutron stars, Optical bursts, Optical observation, Gamma-ray bursts, Surveys, R-process, Transient sources, Gravitational wave sources, Gravitational wave astronomy, Compact objects, Cataclysmic variable stars
A Template-based Approach to the Photometric Classification of SN 1991bg-like Supernovae in the SDSS-II Supernova Survey. The use of SNe Ia to measure cosmological parameters has grown significantly over the past two decades. However, there exists a significant diversity in the SN Ia population that is not well understood. Overluminous SN 1991T-like and subluminous SN 1991bg-like objects are two characteristic examples of peculiar SNe. The identification and classification of such objects is an important step in studying what makes them unique from the remaining SN population. With the upcoming Vera C. Rubin Observatory promising on the order of a million new SNe over a 10 year survey, spectroscopic classifications will be possible for only a small subset of observed targets. As such, photometric classification has become an increasingly important concern in preparing for the next generation of astronomical surveys. Using observations from the Sloan Digital Sky Survey II (SDSS-II) SN Survey, we apply here an empirically based classification technique targeted at the identification of SN 1991bg-like SNe in photometric data sets. By performing dedicated fits to photometric data in the rest-frame redder and bluer bandpasses, we classify 16 previously unidentified 91bg-like SNe. Using SDSS-II host galaxy measurements, we find that these SNe are preferentially found in host galaxies with an older average stellar age than the hosts of normal SNe Ia. We also find that these SNe are found at a further physical distance from the center of their host galaxies. We find no statistically significant bias in host galaxy mass or specific star formation rate for these targets.

Keywords: Observational astronomy, Light curve classification , Type Ia supernovae, Supernovae
Chains of Planets in Mean Motion Resonances Arising from Oligarchic Growth. Exoplanet systems with multiple planets in mean motion resonances have often been hailed as a signpost of disk-driven migration. Resonant chains like Kepler-223 and Kepler-80 consist of a trio of planets with the three-body resonant angle librating and/or with a two-body resonant angle librating for each pair. Here we investigate whether close-in super-Earths and mini-Neptunes forming in situ can lock into resonant chains due to dissipation from a depleted gas disk. We simulate the giant impact phase of planet formation, including eccentricity damping from a gaseous disk, followed by subsequent dynamical evolution over tens of millions of years. In a fraction of simulated systems, we find that planets naturally lock into resonant chains. These planets achieve a chain of near-integer period ratios during the gas-disk stage, experience eccentricity damping that captures them into resonance, stay in resonance as the gas disk dissipates, and avoid subsequent giant impacts, eccentricity excitation, and chaotic diffusion that would dislodge the planets from resonance. Disk conditions that enable planets to complete their formation during the gas-disk stage enable those planets to achieve tight period ratios ≤2 and, if they happen to be near-integer period ratios, lock into resonance. Using the weighting of different disk conditions deduced by MacDonald et al. and forward modeling Kepler selection effects, we find that our simulations of in situ formation via oligarchic growth lead to a rate of observable trios with integer period ratios and librating resonant angles comparable to observed Kepler systems.

Keywords: Exoplanet dynamics, Orbital resonances, Orbital evolution, Exoplanet systems, Gravitational interaction, Exoplanet astronomy, Protoplanetary disks, Exoplanet formation, Planet formation
ALMA Observations and Modeling of the Rotating Outflow in Orion Source I. We present 29SiO(J = 8-7) ν = 0, SiS (J = 19-18) ν = 0, and 28SiO (J = 8-7) ν = 1 molecular line archive observations made with the Atacama Large Millimeter/Submillimeter Array (ALMA) of the molecular outflow associated with Orion Source I. The observations show velocity asymmetries about the flow axis that are interpreted as outflow rotation. We find that the rotation velocity (∼4-8 km s-1) decreases with the vertical distance to the disk. In contrast, the cylindrical radius (∼100-300 au), the expansion velocity (∼2-15 km s-1), and the axial velocity vz (∼-1-10 km s-1) increase with the vertical distance. The mass estimated of the molecular outflow Moutflow ∼ 0.66-1.3 M⊙. Given a kinematic time ∼130 yr, this implies a mass-loss rate ${\dot{M}}_{\mathrm{outflow}}\sim 5.1-10\times {10}^{-3}$ M⊙ yr-1. This massive outflow sets important constraints on disk wind models. We compare the observations with a model of a shell produced by the interaction between an anisotropic stellar wind and an Ulrich accretion flow that corresponds to a rotating molecular envelope in collapse. We find that the model cylindrical radii are consistent with the 29SiO(J = 8-7) ν = 0 data. The expansion velocities and the axial velocities of the model are similar to the observed values, except for the expansion velocity close to the disk (z ∼ ±150 au). Nevertheless, the rotation velocities of the model are a factor ∼3-10 lower than the observed values. We conclude that the Ulrich flow alone cannot explain the rotation observed and other possibilities should be explored, like the inclusion of the angular momentum of a disk wind.

Keywords: Protostars, Stellar winds, Stellar accretion
Cosmological Vlasov-Poisson Simulations of Structure Formation with Relic Neutrinos: Nonlinear Clustering and the Neutrino Mass. We present the results of cosmological simulations of large-scale structure formation with massive neutrinos. The phase-space distribution of the cosmic relic neutrinos is followed, for the first time, by directly integrating the six-dimensional Vlasov-Poisson equations. Our novel approach allows us to represent free streaming and clustering of neutrinos, and their gravitational interaction with cold dark matter accurately. We thus obtain solutions for the collisionless dynamics independent of conventional N-body methods. We perform a suite of hybrid N-body/Vlasov simulations with varying the neutrino mass, and systematically examine the dynamical effects of massive neutrinos on large-scale structure formation. Our simulations show characteristic large-scale clustering of the neutrinos and their coherent streaming motions relative to dark matter. The effective local neutrino "temperature" around massive galaxy clusters varies by several percent with respect to the cosmic mean; the neutrinos in clusters can be hotter or colder depending on the neutrino mass. We study a number of statistics of the large-scale structure and of dark matter halos in comparison with those obtained by N-body simulations and/or by perturbation theory. Our simulations mark an important milestone in numerical cosmology, and pave a new way to study cosmic structure formation with massive neutrinos.

Keywords: Large-scale structure of the universe, Cosmological parameters from large-scale structure, Cosmological neutrinos, Neutrino masses
Compressible Turbulence in the Interstellar Medium: New Insights from a High-resolution Supersonic Turbulence Simulation. The role of supersonic turbulence in structuring the interstellar medium (ISM) remains an unsettled question. Here, this problem is investigated using a new exact law of compressible isothermal hydrodynamic turbulence, which involves two-point correlations in physical space. The new law is shown to have a compact expression that contains a single flux term reminiscent of the incompressible case and a source term with a simple expression whose sign is given by the divergence of the velocity. The law is then used to investigate the properties of such a turbulence at integral Mach number 4 produced by a massive numerical simulation with a grid resolution of $10,{048}^{3}$ points. The flux (resp. source) term was found to have positive (resp. negative) contribution to the total energy cascade rate, which is interpreted as a direct cascade amplified by compression, while their sum is constant in the inertial range. Using a local (in space) analysis it is shown that the source is mainly driven by filamentary structures in which the flux is negligible. Taking positive defined correlations reveals the existence of different turbulent regimes separated by the sonic scale, which determines the scale over which the nonnegligible source modifies the scaling of the flux. Our study provides new insight into the dynamics and structures of supersonic interstellar turbulence.

Keywords: Hydrodynamical simulations, Hydrodynamics, Interstellar filaments, Interstellar medium