Sazuna/UAT_keywords huggingface dataset:
Multiphase Gas Flows in the Nearby Seyfert Galaxy ESO428-G014. Paper I. We present ALMA 230 GHz continuum and CO(2-1) observations of the nearby Compton-thick Seyfert galaxy ESO428-G14, with angular resolution 0"7 (78 pc). CO(2-1) is distributed in clumpy spiral arms, a lopsided circumnuclear ring (CNR) with ∼200 pc radius, and a transverse gas lane with size &lt;100 pc, which crosses the nucleus and connects the two portions of the CNR. The main CO velocity gradient is consistent with a rotating disk with dynamical mass Mdyn = 5 × 109 M☉ within ∼1 kpc. We detect off-plane gas motions with respect to the main disk plane which likely trace a molecular outflow with rate ${\dot{M}}_{\mathrm{of}}\approx 0.1\mbox{--}0.3\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$ , along a biconical structure with radius 700 pc. The CO outflow smoothly joins the warm molecular outflow detected in SINFONI/Very Large Telescope data in the central 170 pc, suggesting that the outflow may cool with increasing distance. Our dynamical modeling of the inner 100 pc region suggests a warped disk or bar, and of fast gas streams which may trace an inflow toward the AGN. The inner warped disk overlaps with the most obscured, CT region seen in X-rays. There, we derive a column density $N({{\rm{H}}}_{2})\approx 2\times {10}^{23}\,{\mathrm{cm}}^{-2}$ , suggesting that molecular gas may contribute significantly to the AGN obscuration. Most of the hard X-ray emitting nuclear region is deprived of cold molecular gas and shows a CO-cavity. The CO-cavity is filled with warm molecular gas traced by H2, confirming that the 3-6 keV continuum and Fe Kα emission are due to scattering from dense ISM clouds.

Keywords: AGN host galaxies, Active galactic nuclei, Galaxy kinematics, Interstellar medium
Habitability and Water Loss Limits on Eccentric Planets Orbiting Main-sequence Stars. A planet's climate can be strongly affected by its orbital eccentricity and obliquity. Here we use a one-dimensional energy balance model modified to include a simple runaway greenhouse (RGH) parameterization to explore the effects of these two parameters on the climate of Earth-like aqua planets—completely ocean-covered planets—orbiting F-, G-, K-, and M-dwarf stars. We find that the range of instellations for which planets exhibit habitable surface conditions throughout an orbit decreases with increasing eccentricity. However, the appearance of temporarily habitable conditions during an orbit creates an eccentric habitable zone (EHZ) that is sensitive to orbital eccentricity and obliquity, planetary latitude, and the spectral type of the host star. We find that the fraction of a planet's orbit over which it exhibits habitable surface conditions is larger on eccentric planets orbiting M-dwarf stars, due to the lower broadband planetary albedos of these planets. Planets with larger obliquities have smaller EHZs, but exhibit warmer climates if they do not enter a snowball state during their orbits. We also find no transient RGH state on planets at all eccentricities. Rather, planets spend their entire orbits either in an RGH or not. For G-dwarf planets receiving 100% of the modern solar constant and with eccentricities above 0.55, an entire Earth ocean inventory can be lost in 3.6 Gyr. M-dwarf planets, due to their larger incident X-ray and extreme ultraviolet flux, can become desiccated in only 690 Myr with eccentricities above 0.38. This work has important implications for eccentric planets that may exhibit surface habitability despite technically departing from the traditional habitable zone as they orbit their host stars.

Keywords: Exoplanets, Elliptical orbits, Planetary atmospheres, Astrobiology, Low mass stars, Solar-terrestrial interactions, Habitable zone, Eccentricity
Inference of Solar Rotation from Perturbations of Acoustic Mode Eigenfunctions. Today's picture of the internal solar rotation rate profile results essentially from helioseismic analyses of frequency splittings of resonant acoustic waves. Here we present another, complementary estimation of the internal solar rotation rate using the perturbation of the shape of the acoustic waves. For this purpose, we extend a global helioseismic approach developed previously for the investigation of the meridional flow to work on the components of the differential rotation. We discuss the effect of rotation on mode eigenfunctions and the observables based thereon. Based on a numerical study using a simulated rotation rate profile, we tailor an inversion approach and also consider the case of the presence of an additional meridional flow. This inversion approach is then applied to data from the Michelson Doppler Imager (MDI) on board the Solar Heliospheric Observatory and the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory. In the end, rotation rate profiles estimated from eigenfunction perturbation and frequency splittings are compared. The rotation rate profiles from the two different approaches are qualitatively in good agreement, especially for the MDI data. Significant differences are obtained at high latitudes &gt;50° and near the subsurface. The result from HMI data shows larger discrepancies between the different methods. We find that the two global helioseismic approaches provide complementary methods for measuring the solar rotation. Comparing the results from different methods may help to reveal systematic influences that affect analyses based on eigenfunction perturbations, like meridional flow measurements.

Keywords: Solar rotation, Solar interior, Helioseismology, Astronomy data analysis, Solar physics, Solar meridional circulation, Active solar chromosphere
Interpreting Observations of Absorption Lines in the Circumgalactic Medium with a Turbulent Medium. Single-phase photoionization equilibrium (PIE) models are often used to infer the underlying physical properties of galaxy halos probed in absorption with ions at different ionization potentials. To incorporate the effects of turbulence, we use the Models of Agitated and Illuminated Hindering and Emitting Media (MAIHEM) code to model an isotropic turbulent medium exposed to a redshift-zero metagalactic UV background, while tracking the ionizations, recombinations, and species-by-species radiative cooling for a wide range of ions. By comparing observations and simulations over a wide range of turbulent velocities, densities, and metallicity with a Markov chain Monte Carlo technique, we find that MAIHEM models provide an equally good fit to the observed low-ionization species compared to PIE models, while reproducing at the same time high-ionization species such as Si IV and O VI. By including multiple phases, MAIHEM models favor a higher metallicity (Z/Z⊙ ≈ 40%) for the circumgalactic medium compared to PIE models. Furthermore, all of the solutions require some amount of turbulence (σ3D $\geqslant $ 26 km s-1). Correlations between turbulence, metallicity, column density, and impact parameter are discussed alongside mechanisms that drive turbulence within the halo.

Keywords: Markov chain Monte Carlo, Circumgalactic medium, Astrochemistry
A Radio Molecular Line Search for Evidence of an O-rich Environment Around Binary in Silicate Carbon Stars. We report observations of oxygen-rich (O-rich) radio molecular line tracers, including H2CO, H2O, and HCO+ toward 28 silicate carbon stars (SCSs). SCSs are special evolved star systems that consist of a carbon star associated with peculiar O-rich circumstellar material. Absorption in the 6 cm ${{\rm{H}}}_{2}\mathrm{CO}$ transition was detected from seven SCSs using the Shanghai 65 m Tianma radio telescope. In order to further investigate their O-rich material, several 3 mm molecular lines including HCO+ and CO were also observed with the Purple Mountain Observatory 13.7 m telescope. Double-peak profiles in some of these lines suggest the possible presence of a companion in the SCS system. A negative association between H2O masers and H2CO absorption was found in our sample of SCSs. The ${{\rm{H}}}_{2}{\rm{O}}$ maser sources may correspond to an earlier evolutionary stage when the circumstellar envelope (CSE) material is O-rich and limited to a compact and denser region. As the star evolves the CSE gradually expands and carbon abundance is enhanced, resulting in the ${{\rm{H}}}_{2}{\rm{O}}$ masers disappearing and H2CO absorption arising.

Keywords: Circumstellar envelopes, Silicon stars, Binary stars, Post-asymptotic giant branch stars, Evolved stars, Carbon stars, Circumstellar matter, Asymptotic giant branch stars, Chemically peculiar stars
The Nucleosynthetic Yields of Core-collapse Supernovae: Prospects for the Next Generation of Gamma-Ray Astronomy. Though the neutrino-driven convection model for the core-collapse explosion mechanism has received strong support in recent years, there are still many uncertainties in the explosion parameters—such as explosion energy, remnant mass, and end-of-life stellar abundances as initial conditions. Using a broad set of spherically symmetric core-collapse simulations we examine the effects of these key parameters on explosive nucleosynthesis and final explosion yields. The post-bounce temperature and density evolution of zero-age main-sequence 15, 20, and 25 solar mass progenitors are post-processed through the Nucleosynthesis Grid nuclear network to obtain detailed explosive yields. In particular, this study focuses on radio isotopes that are of particular interest to the next generation of gamma-ray astronomical observations: 43K, 47Ca, 44Sc, 47Sc, 48V, 48Cr, 51Cr, 52Mn, 59Fe, 56Co, 57Co, and 57Ni. These nuclides may be key in advancing our understanding of the inner workings of core-collapse supernovae by probing the parameters of the explosion engine. We find that the isotopes that are strong indicators of explosion energy are 43K, 47Ca, 44Sc, 47Sc, and 59Fe, those that are dependent on the progenitor structure are 48V, 51Cr, and 57Co, and those that probe neither are 48Cr, 52Mn, 57Ni, and 56Co. We discuss the prospects of observing these radionuclides in supernova remnants.

Keywords: Explosive nucleosynthesis, Core-collapse supernovae, Stellar nucleosynthesis, Gamma-ray astronomy, Gamma-ray transient sources, Supernovae
Application of Synoptic Magnetograms to Global Solar Activity Forecast. Synoptic magnetograms provide us with knowledge about the evolution of magnetic fields on the solar surface and present important information for forecasting future solar activity. In this work, poloidal and toroidal magnetic field components derived from synoptic magnetograms are assimilated, using the Ensemble Kalman Filter method, into a mean-field dynamo model based on Parker's migratory dynamo theory complemented by magnetic helicity conservation. It was found that the predicted toroidal field is in good agreement with observations for almost the entire following solar cycle. However, poloidal field predictions agree with observations only for the first 2-3 yr of the predicted cycle. The results indicate that the upcoming Solar Maximum of Cycle 25 (SC25) is expected to be weaker than the current Cycle 24. The model results show that a deep extended solar activity minimum is expected during 2019-2021, and that the next solar maximum will occur in 2024-2025. The sunspot number at the maximum will be about 50 with an error estimate of 15%-30%. The maximum will likely have a double peak or show extended periods (for 2-2.5 yr) of high activity. According to the hemispheric prediction results, SC25 will start in 2020 in the southern hemisphere, and will have a maximum in 2024 with a sunspot number of about 28. In the northern hemisphere the cycle will be delayed for about 1 yr (with an error of ±0.5 yr), and reach a maximum in 2025 with a sunspot number of about 23.

Keywords: Solar cycle, Solar dynamo, Solar magnetic fields, Solar activity, Sunspot cycle
Prediction of the Sun's Coronal Magnetic Field and Forward-modeled Polarization Characteristics for the 2019 July 2 Total Solar Eclipse. On 2019 July 2 a total solar eclipse—visible across parts of the Southern Pacific Ocean, Chile, and Argentina—enabled observations of the Sun's corona. The structure and emission characteristics of the corona are determined by underlying magnetic fields, which also govern coronal heating and solar eruptive events. However, coronal magnetic field measurements remain an outstanding challenge. Coronal magnetic field models serve an important purpose in this context. Earlier work has demonstrated that the large-scale coronal structure is governed by surface flux evolution and memory buildup, which allows for its prediction on solar rotational timescales. Utilizing this idea and based upon a 51 day forward run of a predictive solar surface flux transport model and a potential field source surface model, we predict the coronal structure of the 2019 July 2 solar eclipse. We also forward model the polarization characteristics of the coronal emission. Our prediction of two large-scale streamer structures and their locations on the east and west limbs of the Sun match eclipse observations reasonably well. We demonstrate that the Sun's polar fields strongly influence the modeled corona, concluding that accurate polar field observations are critical. This study is relevant for coronal magnetometry initiatives envisaged with the Daniel K. Inouye Solar Telescope, Coronal Multichannel Polarimeter and upcoming space-based instruments such as Solar Orbiter, Solar Ultraviolet Imaging Telescope and the Variable Emission Line Coronagraph on board the Indian Space Research Organisation's Aditya-L1 space mission.

Keywords: Magnetohydrodynamics, Solar eclipses, Solar magnetic fields, Solar corona, Polarimetry
Self-consistent Analysis of Stellar Clusters: An Application to HST Data of the Halo Globular Cluster NGC 6752. The Bayesian isochrone fitting using the Markov chain Monte Carlo algorithm is applied, to derive the probability distribution of the parameters age, metallicity, reddening, and absolute distance modulus. We introduce the SIRIUS code by means of simulated color-magnitude diagrams (CMDs), including the analysis of multiple stellar populations (MPs). The population tagging is applied from the red giant branch to the bottom of the main sequence. Through sanity checks using synthetic Hubble Space Telescope CMDs of globular clusters we verify the code reliability in the context of simple and MPs. In such tests, the formal uncertainties in age or age difference, metallicity, reddening, and absolute distance modulus can reach 400 Myr, 0.03 dex, 0.01 mag, and 0.03 mag, respectively. We apply the method to analyze NGC 6752, using Dartmouth stellar evolutionary models. Assuming a single stellar population, we derive an age of 13.7 ± 0.5 Gyr and a distance of ${d}_{\odot }=4.11\pm 0.08\,\mathrm{kpc}$ , with the latter in agreement within 3σ with the inverse Gaia parallax. In the analysis of the MPs, three populations are clearly identified. From the Chromosome Map and UV/Optical two-color diagrams inspection, we found a fraction of stars of 25 ± 5, 46 ± 7, and 29 ± 5 %, for the first, second, and third generations, respectively. These fractions are in good agreement with the literature. An age difference of 500 ± 410 Myr between the first and the third generation is found, with the uncertainty decreasing to 400 Myr when the helium enhancement is taken into account.

Keywords: Globular star clusters, Open star clusters, Hertzsprung Russell diagram, Bayesian statistics
Reevaluation of C<SUB>4</SUB>H Abundance Based on the Revised Dipole Moment. Abnormally large column densities of the carbon-chain molecule, C4H, have been reported in various sources. The main reason for this was supposed to be an underestimated value of the permanent dipole moment of C4H. C4H has a low-lying electronic excited state of 2Π with a large dipole moment in the previous quantum chemical calculations. However, the mixing of the excited state with the ground state 2Σ+ has not been taken into consideration. In the present study, we evaluated this mixing by introducing a multireference configuration interaction. The effective dipole moment of C4H in the ground state was calculated to be 2.10 D, which is about 2.4 times larger than the values used so far. Revised column densities of C4H in dark clouds, low-mass star-forming regions, and the circumstellar envelope IRC+10216 based upon the new value are about a factor of 6 smaller than the previous values. With the revised column densities, exponential smooth decreases are found for the abundances of the C2nH (n = 1-4) molecules with carbon-chain length in these sources, suggesting high similarities among individual formation mechanisms of the C2nH molecules.

Keywords: Interstellar molecules, Circumstellar envelopes, Abundance ratios, Star forming regions, Astrochemistry, Interstellar clouds
The Intriguing Parsec-scale Radio Structure in the "Offset AGN" KISSR 102. We report the detection of an intriguing parsec-scale radio source in the "offset AGN" candidate, KISSR 102. The elliptical host galaxy includes two optical nuclei at a projected separation of 1.54 kpc, N1 and N2, to the southeast and northwest, respectively. Phase-referenced Very Long Baseline Array observations at 1.5 and 4.9 GHz of this low ionization nuclear emission line region galaxy have detected double radio components (A and B) at a projected separation of 4.8 parsec at 1.5 GHz, and another partially resolved double radio structure at 4.9 GHz coincident with the brighter radio component A. These radio detections are confined to the optical nucleus N1. The brightness temperatures of all the detected radio components are high, ≳108 K, consistent with them being components of a radio active galactic nucleus (AGN). The 1.5-4.9 GHz spectral index is inverted (α ∼ + 0.64 ± 0.08) for component A and steep for component B (α ≲ -1.6). The dramatic change in the spectral indices of A and B is inconsistent with it being a typical "core-jet" structure from a single AGN, or the mini-lobes of a compact symmetric object. To be consistent with a "core-jet" structure, the jet in KISSR 102 would need to be undergoing strong jet-medium interaction with dense surrounding media resulting in a drastic spectral steepening of the jet. Alternatively, the results could be consistent with the presence of a parsec-scale binary radio AGN, which is the end result of a three-body interaction involving three supermassive black holes in the center of KISSR 102.

Keywords: Black holes, Very long baseline interferometry, Emission line galaxies, LINER galaxies, Seyfert galaxies, Galaxy mergers, Radio continuum emission
Close-in Exoplanets as Candidates for Strange Quark Matter Objects. Since the true ground state of hadrons may be strange quark matter (SQM), pulsars may actually be strange stars rather than neutron stars. According to this SQM hypothesis, strange planets can also stably exist. The density of normal matter planets can hardly be higher than 30 g cm-3. They will be tidally disrupted when the orbital radius is less than ∼5.6 × 1010 cm, or when the orbital period (Porb) is less than ∼6100 s. However, an SQM planet can safely survive even when it is very close to the host, due to its high density. This feature can help us identify SQM objects. Here, we have tried to search for SQM objects among close-in exoplanets orbiting around pulsars. It is found that four pulsar planets (XTE J1807-294 b, XTE J1751-305 b, PSR 0636 b, PSR J1807-2459A b) completely meet the criterion of Porb &lt; 6100 s, and are thus good candidates for SQM planets. The periods of two other planets (PSR J1719-14 b and PSR J2051-0827 b) are only slightly larger than the criterion value. They could be regarded as potential candidates. Additionally, we find that the periods of five white dwarf planets (GP Com b, V396 Hya b, J1433 b, WD 0137-349 b, and SDSS J1411+2009 b) are less than 0.1 day; they might also be SQM planets. Gravitational wave emissions from these close-in planetary systems are calculated from the view of various gravitational wave detectors.

Keywords: Neutron stars, Gravitational waves, Exoplanet systems, Pulsars
First Resolved Dust Continuum Measurements of Individual Giant Molecular Clouds in the Andromeda Galaxy. In our local Galactic neighborhood, molecular clouds are best studied using a combination of dust measurements, to determine robust masses, sizes, and internal structures of the clouds, and molecular-line observations to determine cloud kinematics and chemistry. We present here the first results of a program designed to extend such studies to nearby galaxies beyond the Magellanic Clouds. Utilizing the wideband upgrade of the Submillimeter Array (SMA) at 230 GHz, we have obtained the first continuum detections of the thermal dust emission on sub-GMC scales (∼15 pc) within the Andromeda galaxy (M31). These include the first resolved continuum detections of dust emission from individual giant molecular clouds (GMCs) beyond the Magellanic Clouds. Utilizing a powerful capability of the SMA, we simultaneously recorded CO(2-1) emission with identical (u, V) coverage, astrometry, and calibration, enabling the first measurements of the CO conversion factor, αCO(2-1), toward individual GMCs across an external galaxy. Our direct measurement yields an average CO-to-dust mass conversion factor of ${\alpha }_{\mathrm{CO}-\mathrm{dust}}^{{\prime} }=0.042\pm 0.018$ M⊙ (K km s-1 pc2)-1 for the J = 2-1 transition. This value does not appear to vary with galactocentric radius. Assuming a constant gas-to-dust ratio of 136, the resulting αCO = 5.7 ± 2.4 M⊙ (K km s-1 pc2)-1 for the 2-1 transition is in excellent agreement with that of GMCs in the Milky Way, given the uncertainties. Finally, using the same analysis techniques, we compare our results with observations of the local Orion molecular clouds, placed at the distance of M31 and simulated to appear as they would if observed by the SMA.

Keywords: Giant molecular clouds, Dust continuum emission, Andromeda Galaxy, CO line emission
The Presupernova Core Mass-Radius Relation of Massive Stars: Understanding Its Formation and Evolution. We present a fine grid of solar metallicity models of massive stars (320 in the range 12 ≤ M( ${M}_{\odot }$ ) ≤ 27.95), extending from the main sequence up to the onset of the collapse, in order to quantitatively determine how their compactness ξ2.5, defined by O'Connor &amp; Ott, scales with the carbon-oxygen core mass at the beginning of core collapse. We find a well defined, nonmonotonic (but not scattered) trend of the compactness with the carbon-oxygen core mass that is strictly (and mainly) correlated to the behavior, I.e., birth, growth, and disappearance, of the various carbon convective episodes that follow one another during the advanced evolutionary phases. Though both the mass size of the carbon-oxygen core and the amount of 12C left by the central He burning play a major role in sculpting the final mass-radius relation, it is the abundance of 12C that is ultimately responsible for the final degree of compactness of a star, because it controls the ability of the carbon-burning shell to advance in mass before the final collapse.

Keywords: Stellar interiors, Massive stars, Core-collapse supernovae, Stellar evolution