Sazuna/UAT_keywords huggingface dataset:
GROWTH on S190425z: Searching Thousands of Square Degrees to Identify an Optical or Infrared Counterpart to a Binary Neutron Star Merger with the Zwicky Transient Facility and Palomar Gattini-IR. The third observing run by LVC has brought the discovery of many compact binary coalescences. Following the detection of the first binary neutron star merger in this run (LIGO/Virgo S190425z), we performed a dedicated follow-up campaign with the Zwicky Transient Facility (ZTF) and Palomar Gattini-IR telescopes. The initial skymap of this single-detector gravitational wave (GW) trigger spanned most of the sky observable from Palomar Observatory. Covering 8000 deg2 of the initial skymap over the next two nights, corresponding to 46% integrated probability, ZTF system achieved a depth of ≈21 m AB in g- and r-bands. Palomar Gattini-IR covered 2200 square degrees in J-band to a depth of 15.5 mag, including 32% integrated probability based on the initial skymap. The revised skymap issued the following day reduced these numbers to 21% for the ZTF and 19% for Palomar Gattini-IR. We narrowed 338,646 ZTF transient “alerts” over the first two nights of observations to 15 candidate counterparts. Two candidates, ZTF19aarykkb and ZTF19aarzaod, were particularly compelling given that their location, distance, and age were consistent with the GW event, and their early optical light curves were photometrically consistent with that of kilonovae. These two candidates were spectroscopically classified as young core-collapse supernovae. The remaining candidates were ruled out as supernovae. Palomar Gattini-IR did not identify any viable candidates with multiple detections only after merger time. We demonstrate that even with single-detector GW events localized to thousands of square degrees, systematic kilonova discovery is feasible.

Keywords: Gravitational wave astronomy, Optical telescopes, Transient detection
The Nuclear Filaments inside the Circumnuclear Disk in the Central 0.5 pc of the Galactic Center. We present CS(7-6) line maps toward the central parsec of the Galactic center, conducted with the Atacama Large Millimeter/submillimeter Array. The primary goal is to find and characterize the gas structure in the inner cavity of the circumnuclear disk (CND) in high resolution (1.″3 = 0.05 pc). Our large field-of-view mosaic maps—combining interferometric and single-dish data that recover extended emission—provide a first homogeneous look to resolve and link the molecular streamers in the CND with the neutral nuclear filaments newly detected within the central cavity of the CND. We find that the nuclear filaments are rotating with Keplerian velocities in a nearly face-on orbit with an inclination angle of ∼10°-20° (radius ≤ 0.5 pc). This is in contrast to the CND which is highly inclined at ∼65°-80° (radius ∼2-5 pc). Our analysis suggests a highly warped structure from the CND to the nuclear filaments. This result may hint that the nuclear filaments and the CND were created by different external clouds passing by Sgr A*.

Keywords: Galactic center
How to Fuel an AGN: Mapping Circumnuclear Gas in NGC 6240 with ALMA. Dynamical black hole mass measurements in some gas-rich galaxy mergers indicate that they are overmassive relative to their host galaxy properties. Overmassive black holes in these systems present a conflict with the standard progression of galaxy merger-quasar evolution; an alternative explanation is that a nuclear concentration of molecular gas driven inward by the merger is affecting these dynamical black hole mass estimates. We test for the presence of such gas near the two black holes in NGC 6240 using long-baseline ALMA Band 6 observations (beam size 0.″06 × 0.″03 or 30 pc × 15 pc). We find (4.2-9.8) × 107 M ⊙ and (1.2-7.7) × 108 M ⊙ of molecular gas within the resolution limit of the original black hole mass measurements for the north and south black holes, respectively. In the south nucleus, this measurement implies that 6%-89% of the original black hole mass measurement actually comes from molecular gas, resolving the tension in the original black hole scaling relations. For the north, only 5%-11% is coming from molecular gas, suggesting the north black hole is actually overmassive. Our analysis provides the first measurement of significant molecular gas masses contaminating dynamical black hole mass measurements. These high central molecular gas densities further present a challenge to theoretical black hole accretion prescriptions, which often assume accretion proceeds rapidly through the central 10 pc.

Keywords: Accretion, Supermassive black holes, Molecular gas, Bondi accretion, Active galactic nuclei
Half-mass Radii of Quiescent and Star-forming Galaxies Evolve Slowly from 0 ≲ z ≤ 2.5: Implications for Galaxy Assembly Histories. We use high-resolution, multiband imaging of ∼16,500 galaxies in the CANDELS fields at 0 ≲ z ≤ 2.5 to study the evolution of color gradients and half-mass radii over cosmic time. We find that galaxy color gradients at fixed mass evolve rapidly between z ∼ 2.5 and z ∼ 1, but remain roughly constant below z ∼ 1. This result implies that the sizes of both star-forming and quiescent galaxies increase much more slowly than previous studies found using half-light radii. The half-mass radius evolution of quiescent galaxies is fully consistent with a model that uses observed minor merger rates to predict the increase in sizes due to the accretion of small galaxies. Progenitor bias may still contribute to the growth of quiescent galaxies, particularly if we assume a slower timescale for the minor merger growth model. The slower half-mass radius evolution of star-forming galaxies is in tension with cosmological simulations and semianalytic galaxy models. Further detailed, consistent comparisons with simulations are required to place these results in context. This work is based on observations taken by the CANDELS Multi-Cycle Treasury Program and the 3D-HST Treasury Program with the NASA/ESA HST, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Keywords: Galaxy formation, Galaxy structure, Galaxy evolution, Galaxy radii
SN2018kzr: A Rapidly Declining Transient from the Destruction of a White Dwarf. We present SN2018kzr, the fastest declining supernova-like transient, second only to the kilonova, AT2017gfo. SN2018kzr is characterized by a peak magnitude of M  r  = -17.98, a peak bolometric luminosity of ∼1.4 × 1043 erg s-1, and a rapid decline rate of 0.48 ± 0.03 mag day-1 in the r band. The bolometric luminosity evolves too quickly to be explained by pure 56Ni heating, necessitating the inclusion of an alternative powering source. Incorporating the spin-down of a magnetized neutron star adequately describes the lightcurve and we estimate a small ejecta mass of M ej = 0.10 ± 0.05 M ☉. Our spectral modeling suggests the ejecta is composed of intermediate mass elements including O, Si, and Mg and trace amounts of Fe-peak elements, which disfavors a binary neutron star merger. We discuss three explosion scenarios for SN2018kzr, given the low ejecta mass, intermediate mass element composition, and high likelihood of additional powering—the core collapse of an ultra-stripped progenitor, the accretion induced collapse (AIC) of a white dwarf, and the merger of a white dwarf and neutron star. The requirement for an alternative input energy source favors either the AIC with magnetar powering or a white dwarf-neutron star merger with energy from disk wind shocks.

Keywords: Magnetars, White dwarf stars, Supernovae
The Precision of Mass Measurements Required for Robust Atmospheric Characterization of Transiting Exoplanets. Two of Transiting Exoplanet Survey Satellite’s major science goals are to measure masses for 50 planets smaller than 4 Earth radii and to discover high-quality targets for atmospheric characterization efforts. It is important that these two goals are linked by quantifying what precision of mass constraint is required to yield robust atmospheric properties of planets. Here, we address this by conducting retrievals on simulated James Webb Space Telescope transmission spectra under various assumptions for the degree of uncertainty in the planets mass for a representative population of seven planets ranging from terrestrials to warm Neptunes to hot Jupiters. Only for the cloud-free, low-metallicity gas giants are we able to infer exoplanet mass from transmission spectroscopy alone, to ∼10% accuracy. For low-metallicity cases (&lt;4× solar) we are able to accurately constrain atmospheric properties without prior knowledge of the planet’s mass. For all other cases (including terrestrial-like planets), atmospheric properties can only be inferred with a mass precision of better than ±50%. At this level, though, the widths of the posterior distributions of the atmospheric properties are dominated by the uncertainties in mass. With a precision of ±20%, the widths of the posterior distributions are dominated by the spectroscopic data quality. Therefore, as a rule of thumb, we recommend a ±50% mass precision for initial atmospheric characterization and a ±20% mass precision for more detailed atmospheric analyses.

Keywords: Planetary atmospheres, Exoplanet atmospheres
Propagation of Solar Energetic Particles in the Outer Heliosphere: Interplay between Scattering and Adiabatic Focusing. The turbulence and spatial nonuniformity of the guide magnetic field cause two competitive effects, namely, the scattering effect and the adiabatic focusing effect, respectively. In this work, we numerically solve the five-dimensional Fokker-Planck transport equation to investigate the radial evolutions of these important effects undergone by the solar energetic particles (SEPs) propagating through interplanetary space. We analyze the interplay process between the scattering and adiabatic focusing effects in the context of three-dimensional propagation, with special attention to the scenario of the outer heliosphere, in which some peculiar SEP phenomena are found and explained. We also discuss the radial dependence of the SEP peak intensities from the inner through the outer heliosphere, and conclude that it cannot be simply described by a single functional form such as R -α  (R is radial distance), which is often used.

Keywords: Interplanetary medium, Heliosphere, Interplanetary turbulence, Solar energetic particles, Solar magnetic fields, Solar particle emission
Constraining Planetary Gas Accretion Rate from Hα Line Width and Intensity: Case of PDS 70 b and c. Recent observations of protoplanets embedded in circumstellar disks have shed light on the planet formation process. In particular, detection of hydrogen Balmer-line (Hα) emission gives direct constraints on late-stage accretion onto gas giants. Very recently Haffert et al. measured the spectral line widths, in addition to intensities, of {{H}}α emission from the two protoplanets orbiting PDS 70. Here, we study these protoplanets by applying radiation-hydrodynamic models of the shock-heated accretion flow onto protoplanets that Aoyama et al. have recently developed. As a result, we demonstrate that Hα line widths combined with intensities lead to narrowing down the possible ranges of the protoplanetary accretion rate and/or mass significantly. While the current spectral resolution is not high enough to derive a definite conclusion regarding their accretion process, high-resolution spectral imaging of growing protoplanets is highly promising.

Keywords: Accretion, H I line emission, Line intensities, Shocks, Exoplanet formation, Extrasolar gaseous giant planets, Planet formation
Direct Detection of Solar Angular Momentum Loss with the Wind Spacecraft. The rate at which the solar wind extracts angular momentum (AM) from the Sun has been predicted by theoretical models for many decades, and yet we lack a conclusive measurement from in situ observations. In this Letter we present a new estimate of the time-varying AM flux in the equatorial solar wind, as observed by the Wind spacecraft from 1994 to 2019. We separate the AM flux into contributions from the protons, alpha particles, and magnetic stresses, showing that the mechanical flux in the protons is ∼3 times larger than the magnetic field stresses. We observe the tendency for the AM flux of fast wind streams to be oppositely signed to the slow wind streams, as noted by previous authors. From the average total flux, we estimate the global AM loss rate of the Sun to be 3.3 × 1030 erg, which lies within the range of various magnetohydrodynamic wind models in the literature. This AM loss rate is a factor of ∼2 weaker than required for a Skumanich-like rotation period evolution ({{{Ω }}}*  \propto stellar age-1/2), which should be considered in studies of the rotation period evolution of Sun-like stars.

Keywords: Magnetohydrodynamics, Solar rotation, Solar wind, Solar evolution, Stellar rotation, Stellar evolution
Mapping Electron Temperature Variations across a Spiral Arm in NGC 1672. We report one of the first extragalactic observations of electron temperature variations across a spiral arm. Using Multi Unit Spectroscopic Explorer mosaic observations of the nearby galaxy NGC 1672, we measure the [N II]λ5755 auroral line in a sample of 80 H II regions in the eastern spiral arm of NGC 1672. We discover systematic temperature variations as a function of distance perpendicular to the spiral arm. The electron temperature is lowest on the spiral arm itself and highest on the downstream side. Photoionization models of different metallicity, pressure, and age of the ionizing source are explored to understand what properties of the interstellar medium drive the observed temperature variations. An azimuthally varying metallicity appears to be the most likely cause of the temperature variations. The electron temperature measurements solidify recent discoveries of azimuthal variations of oxygen abundance based on strong lines, and rule out the possibility that the abundance variations are artifacts of the strong-line calibrations.

Keywords: Spiral galaxies, Interstellar abundances, Chemical abundances, Spiral arms, Interstellar medium, H II regions
Molecular Gas in the Outflow of the Small Magellanic Cloud. We report the first evidence of molecular gas in two atomic hydrogen (H I) clouds associated with gas outflowing from the Small Magellanic Cloud (SMC). We used the Atacama Pathfinder Experiment to detect and spatially resolve individual clumps of 12CO(2 → 1) emission in both clouds. CO clumps are compact (∼10 pc) and dynamically cold (line widths ≲ 1 {km} {{{s}}}-1). Most CO emission appears to be offset from the peaks of the H I emission, some molecular gas lies in regions without a clear H I counterpart. We estimate a total molecular gas mass of {M}mol}≃ {10}3{--}{10}4 {M}☉  in each cloud and molecular gas fractions up to 30% of the total cold gas mass (molecular + neutral). Under the assumption that this gas is escaping the galaxy, we calculated a cold gas outflow rate of {\dot{M}}gas}≃ 0.3{--}1.8 {M}☉  {yr}}-1 and mass loading factors of β ≃ 3{--}12 at a distance larger than 1 kpc. These results show that relatively weak starburst-driven winds in dwarf galaxies like the SMC are able to accelerate significant amounts of cold and dense matter and inject it into the surrounding environment.

Keywords: Molecular gas, Interstellar phases, Stellar feedback, Small Magellanic Cloud, Galaxy winds, Interstellar medium, CO line emission, Magellanic Clouds
The Shadow of a Spherically Accreting Black Hole. We explore a simple spherical model of optically thin accretion on a Schwarzschild black hole, and study the properties of the image as seen by a distant observer. We show that a dark circular region in the center—a shadow—is always present. The outer edge of the shadow is located at the photon ring radius {b}ph}\equiv \sqrt{27}{r}g, where {r}g={GM}/{c}2 is the gravitational radius of the accreting mass M. The location of the shadow edge is independent of the inner radius at which the accreting gas stops radiating. The size of the observed shadow is thus a signature of the spacetime geometry and it is hardly influenced by accretion details. We briefly discuss the relevance of these results for the Event Horizon Telescope image of the supermassive black hole in M87.

Keywords: Accretion, Strong gravitational lensing, Black holes
Stellar Velocity Dispersion of a Massive Quenching Galaxy at z = 4.01. We present the first stellar velocity dispersion measurement of a massive quenching galaxy at z = 4. The galaxy is first identified as a massive z ≥ 4 galaxy with suppressed star formation from photometric redshifts based on deep multiband data. A follow-up spectroscopic observation with MOSFIRE on Keck revealed strong multiple absorption features, which are identified as Balmer lines, giving a secure redshift of z = 4.01. This is the most distant quiescent galaxy known to date. Thanks to the high S/N of the spectrum, we are able to estimate the stellar velocity dispersion, σ =268+/- 59 {km} {{{s}}}-1, making a significant leap from the previous highest redshift measurement at z = 2.8. Interestingly, we find that the velocity dispersion is consistent with that of massive galaxies today, implying no significant evolution in velocity dispersion over the last 12 Gyr. Based on a stringent upper limit on its physical size from deep optical images (r eff &lt; 1.3 kpc), we find that its dynamical mass is consistent with the stellar mass inferred from photometry. Furthermore, the galaxy is located on the mass fundamental plane extrapolated from lower redshift galaxies. The observed no strong evolution in σ suggests that the mass in the core of massive galaxies does not evolve significantly, while most of the mass growth occurs in the outskirts of the galaxies, which also increases the size. This picture is consistent with a two-phase formation scenario in which mass and size growth is due to accretion in the outskirts of galaxies via mergers. Our results imply that the first phase may be completed as early as z ∼ 4.

Keywords: Galaxy formation, Galaxy dynamics, Galaxy evolution, Elliptical galaxies, High-redshift galaxies
Dark Matter Signatures of Supermassive Black Hole Binaries. A natural consequence of the galaxy formation paradigm is the existence of supermassive black hole (SMBH) binaries. Gravitational perturbations from a far-away SMBH companion can induce high orbital eccentricities on dark matter (DM) particles orbiting the primary SMBH via the eccentric Kozai-Lidov mechanism. This process yields an influx of DM particles into the primary SMBH ergosphere, where test particles linger for long timescales. This influx results in high self-gravitating densities, forming a DM clump that is extremely close to the SMBH. In such a situation, the gravitational-wave (GW) emission between the dark matter clump and the SMBH is potentially detectable by LISA. If dark matter self-annihilates, the high densities of the clump will result in a unique codetection of GW emission and high-energy electromagnetic signatures.

Keywords: Double quasars, Black hole physics, Supermassive black holes, Galaxy nuclei, Dark matter
The Galaxy’s Gas Content Regulated by the Dark Matter Halo Mass Results in a Superlinear M <SUB>BH</SUB>-M <SUB>⋆</SUB> Relation. Supermassive black holes (SMBHs) are tightly correlated with their hosts, but the origin of such connection remains elusive. To explore the cosmic buildup of this scaling relation, we present an empirically motivated model that tracks galaxy and SMBH growth down to z = 0. Starting from a random mass seed distribution at z = 10, we assume that each galaxy evolves on the star-forming “main sequence” (MS) and each BH follows the recently derived stellar mass (M ⋆) dependent ratio between BH accretion rate and star formation rate, going as {BHAR}/{SFR}\propto {M}\star 0.73[+0.22,-0.29]. Our simple recipe naturally describes the BH-galaxy buildup in two stages. At first, the SMBH lags behind the host that evolves along the MS. Later, as the galaxy grows in M ⋆, our M ⋆-dependent BHAR/SFR induces a superlinear BH growth, as {M}BH}\propto {M}\star 1.7. According to this formalism, smaller BH seeds increase their relative mass faster and earlier than bigger BH seeds, at fixed M ⋆, thus setting along a gradually tighter M BH-M ⋆ locus toward higher M ⋆. Assuming reasonable values of the radiative efficiency ɛ ∼ 0.1, our empirical trend agrees with both high-redshift model predictions and intrinsic M BH-M ⋆ relations of local BHs. We speculate that the observed nonlinear BH-galaxy buildup is reflected in a twofold behavior with dark matter halo mass (M DM), displaying a clear turnover at M DM ∼ 2 × 1012 M ⊙. While supernovae-driven feedback suppresses BH growth in smaller halos ({BHAR}/{SFR}\propto {M}DM}1.6), above the M DM threshold cold gas inflows possibly fuel both BH accretion and star formation in a similar fashion ({BHAR}/{SFR}\propto {M}DM}0.3).

Keywords: AGN host galaxies, Galaxy dark matter halos, Supermassive black holes, Active galaxies, Galaxy evolution
Wide Bandwidth Observations of Pulsars C, D, and J in 47 Tucanae. We report the first wide-band observations of pulsars C, D, and J in the globular cluster 47 Tucanae (NGC 104) using the Ultra-Wideband Low (UWL) receiver system recently installed on the Parkes 64 m radio telescope. The wide frequency range of the UWL receiver (704-4032 MHz), along with the well-calibrated system, allowed us to obtain flux density measurements and polarization pulse profiles. The mean pulse profiles have significant linear and circular polarization, allowing for determination of the Faraday rotation measure for each pulsar. Precise measurements of the dispersion measures show a significant deviation in the value for pulsar D compared to earlier results. Searches for new pulsars in the cluster are ongoing and we have determined optimal bands for such searches using the Parkes UWL receiver system.

Keywords: Globular star clusters, Pulsars, Radio continuum emission
Constraining X-Ray Coronal Size with Transverse Motion of AGN Ultra-fast Outflows. One of the canonical physical properties of ultra-fast outflows (UFOs) seen in a diverse population of active galactic nuclei is its seemingly very broad width (i.e., ∆v ≳ 10,000 km s-1), a feature often required for X-ray spectral modeling. While unclear to date, this condition is occasionally interpreted and justified as internal turbulence within the UFOs for simplicity. In this work, we exploit a transverse motion of a three-dimensional accretion disk-wind, an essential feature of nonradial outflow morphology unique to magnetohydrodynamic outflows. We argue that at least part of the observed line width of UFOs may reflect the degree of transverse velocity gradient due to Doppler broadening around a putative compact X-ray corona in the proximity of a black hole. In this scenario, line broadening is sensitive to the geometrical size of the corona, R  c . We calculate the broadening factor as a function of coronal radius R  c  and velocity smearing factor f sm at a given plasma position. We demonstrate, as a case study of the quasar, PDS 456, that the spectral analysis favors a compact coronal size of R  c /R  g  ≲ 10 where R  g  is gravitational radius. Such a compact corona is long speculated from both an X-ray reverberation study and the lamppost model for disk emission also consistent with microlensing results. Combination of such a transverse broadening around a small corona can be a direct probe of a substantial rotational motion perhaps posing a serious challenge to radiation-driven wind viewpoint.

Keywords: Accretion, Black hole physics, Magnetohydrodynamics, High energy astrophysics, Seyfert galaxies, X-ray active galactic nuclei