Sazuna/UAT_keywords huggingface dataset:
Final Masses of Giant Planets. III. Effect of Photoevaporation and a New Planetary Migration Model. We herein develop a new simple model for giant planet formation that predicts the final mass of a giant planet born in a given disk by adding the disk mass loss due to photoevaporation and a new type II migration formula to our previous model. The proposed model provides some interesting results. First, it gives universal evolution tracks in the diagram of planetary mass and orbital radius, which clarifies how giant planets migrate at growth in the runaway gas accretion stage. Giant planets with a few Jupiter masses or less suffer only a slight radial migration in the runaway gas accretion stage. Second, the final mass of giant planets is approximately given as a function of only three parameters: the initial disk mass at the starting time of runaway gas accretion onto the planet, the mass-loss rate due to photoevaporation, and the starting time. On the other hand, the final planet mass is almost independent of the disk radius, viscosity, and planetary orbital radius. The obtained final planet mass is ≲10% of the initial disk mass. Third, the proposed model successfully explains properties in the mass distribution of giant exoplanets with the mass distribution of observed protoplanetary disks for a reasonable range of the mass-loss rate due to photoevaporation.

Keywords: Exoplanet dynamics, Exoplanet formation, Extrasolar gaseous giant planets
Wide-field Survey of Dwarf Satellite Systems around 10 Hosts in the Local Volume. We present the results of an extensive search for dwarf satellite galaxies around 10 primary host galaxies in the Local Volume (LV, D &lt; 12 Mpc) using archival CFHT/MegaCam imaging data. The hosts span a wide range in properties, with stellar masses ranging from that of the Large Magellanic Cloud to ∼3 times that of the Milky Way. The surveyed hosts are: NGC 1023, NGC 1156, NGC 2903, NGC 4258, NGC 4565, NGC 4631, NGC 5023, M51, M64, and M104. We detect satellite candidates using a consistent semi-automated detection algorithm that is optimized for the detection of low surface brightness objects. Depending on the host, our completeness limit is Mg ∼ -8 to -10 (assuming the distance of the host). We detect objects with surface brightness down to μ0,g∼ 26 mag arcsec-2 at ≳90% completeness. The survey areas of the six best-surveyed hosts cover most of the inner projected R&lt; 150 kpc area, which will roughly double the number of massive LV hosts surveyed at this level of area and luminosity completeness, once distances are measured for the candidates. The number of detected candidates range from 1 around M64 to 33 around NGC 4258. In total, 155 candidates are found, of which 93 are new. While we defer an analysis of the satellite luminosity functions of the hosts until distance information is available for the candidates, we do show that the candidates are primarily red, spheroidal systems with properties roughly consistent with known satellites in the Local Group.

Keywords: Galaxy formation, Dwarf galaxies, Astronomical methods
Morphology of TeV Gamma-Ray Emission from the Kiloparsec-scale Jets in Radio Galaxies. TeV γ rays are observed from a few nearby radio galaxies whose jets are viewed at relatively large angles toward the observer. This emission can be produced in kiloparsec-scale jets whose Lorentz factors are decelerated from values of the order of several at parsec-scale distances. We consider in detail the model in which TeV γ-ray emission is produced by the relativistic electrons in kiloparsec-scale jets that comptonize strongly beamed radiation from inner (parsec-scale) jets. As an example, we study the morphology of the TeV γ-ray emission from the decelerated kiloparsec-scale jet in the nearby radio galaxy Cen A. We show that TeV γ-ray emission can extend throughout kiloparsec-scale distances, as it is relatively smoothly distributed along jets for some parameters of the model we consider. Investigation of the morphological structure of such specific γ-ray emission by the future Cerenkov Telescope Array should provide important constraints on the content and dynamics of the kiloparsec-scale jet in Cen A.

Keywords: Gamma-ray sources, Active galactic nuclei
Probing the Bright End of the Rest-frame Ultraviolet Luminosity Function at z = 8-10 with Hubble Pure-parallel Imaging. Looking for bright galaxies born in the early universe is fundamental to investigating the Epoch of Reionization, the era when the first stars and galaxies ionized the intergalactic medium. We utilize Hubble Space Telescope pure-parallel imaging to select galaxy candidates at a time 500-650 million years after the Big Bang, which corresponds to redshifts z ∼ 8-10. These data come from the Brightest of Reionizing Galaxies Survey (BoRG) Cycle 22 data set, which consists of pure-parallel imaging in ∼90 different lines of sight that sum up to an area of ∼420 arcmin2. This survey uses five filters and has the advantage (compared to the Cycle 21 BoRG program) of including imaging in the JH140 band, covering continuous wavelengths from the visible to near-infrared (λ = 0.35-1.7 μm). This allows us to perform a reliable selection of galaxies at z ≥ 8 using the photometric-redshift technique. We use these galaxy candidates to constrain the bright end of the rest-frame ultraviolet luminosity function in this epoch. These candidates are excellent targets for follow-up observations, particularly with the James Webb Space Telescope.

Keywords: Observational cosmology, Galaxy evolution, Reionization, Random Forests, High-redshift galaxies
LATIS: The Lyα Tomography IMACS Survey. We introduce LATIS, the Lyα Tomography IMACS Survey, a spectroscopic survey at Magellan designed to map the z = 2.2-2.8 intergalactic medium (IGM) in three dimensions by observing the Lyα forest in the spectra of galaxies and QSOs. Within an area of 1.7 deg2, we will observe approximately half of ≳L* galaxies at z = 2.2-3.2 for typically 12 hr, providing a dense network of sightlines piercing the IGM with an average transverse separation of 2.5 h-1 comoving Mpc (1 physical Mpc). At these scales, the opacity of the IGM is expected to be closely related to the dark matter density, and LATIS will therefore map the density field in the z ∼ 2.5 universe at ∼Mpc resolution over the largest volume to date. Ultimately, LATIS will produce approximately 3800 spectra of z = 2.2-3.2 galaxies that probe the IGM within a volume of 4 × 106h-3 Mpc3, large enough to contain a representative sample of structures from protoclusters to large voids. Observations are already complete over one-third of the survey area. In this paper, we describe the survey design and execution. We present the largest IGM tomographic maps at comparable resolution yet made. We show that the recovered matter overdensities are broadly consistent with cosmological expectations based on realistic mock surveys, that they correspond to galaxy overdensities, and that we can recover structures identified using other tracers. LATIS is conducted in Canada-France-Hawaii Telescope Legacy Survey fields, including COSMOS. Coupling the LATIS tomographic maps with the rich data sets collected in these fields will enable novel studies of environment-dependent galaxy evolution and the galaxy-IGM connection at cosmic noon.

Keywords: Dark matter distribution, High-redshift galaxy clusters, Lyman alpha forest, Galaxy environments, Intergalactic medium
Effects of Symmetry Energy on the Equation of State for Simulations of Core-collapse Supernovae and Neutron-star Mergers. We construct a new equation of state (EOS) for numerical simulations of core-collapse supernovae and neutron-star mergers based on an extended relativistic mean-field model with a small symmetry energy slope L, which is compatible with both experimental nuclear data and recent observations of neutron stars. The new EOS table (EOS4) based on the extended TM1 (TM1e) model with L = 40 MeV is designed in the same tabular form and compared with the commonly used Shen EOS (EOS2) based on the original TM1 model with L=110.8 MeV. This is convenient and useful for performing numerical simulations and examining the influences of symmetry energy and its density dependence on astrophysical phenomena. In comparison with the TM1 model used in EOS2, the TM1e model provides a similar maximum neutron-star mass but smaller radius and tidal deformability for a 1.4M⊙ neutron star, which is more consistent with current constraints. By comparing the phase diagram and thermodynamic quantities between EOS4 and EOS2, it is found that the TM1e model predicts a relatively larger region of nonuniform matter and softer EOS for neutron-rich matter. Significant differences between EOS4 and EOS2 are observed in the case with low proton fraction, while the properties of symmetric matter remain unchanged.

Keywords: Neutron stars, Core-collapse supernovae, Compact objects
The Trigger Mechanism of Recurrent Solar Active Region Jets Revealed by the Magnetic Properties of a Coronal Geyser Site. Solar active region jets are small-scale collimated plasma eruptions that are triggered from magnetic sites embedded in sunspot penumbral regions. Multiple trigger mechanisms for recurrent jets are under debate. Vector magnetic field data from Solar Dynamics Observatory (SDO) Helioseismic and Magnetic Imager (HMI) observations are used to analyze a prolific photospheric configuration, identified in extreme ultraviolet observations as a "coronal geyser," that triggered a set of at least 10 recurrent solar active region jets. We focus on interpreting the magnetic fields of small-scale flaring sites aiming to understand the processes that govern recurrent jet eruptions. We perform a custom reprocessing of the SDO-HMI products, including disambiguation and uncertainty estimation. We scrutinized the configuration and dynamics of the photospheric magnetic structures. The magnetic configuration is described, via the analysis of the photospheric magnetic vertical fields, to identify the process that is responsible for driving the jet eruptions. We report that the two widely debated magnetic trigger processes, namely magnetic flux cancellation and magnetic flux emergence, appear to be responsible on a case by case basis for generating each eruption in our set. We find that 4 out of 10 jets were due to flux cancellation, while the rest were clearly not and were more likely due to flux emergence.

Keywords: Solar magnetic flux emergence, Solar photosphere, Solar magnetic reconnection, Astronomy data analysis, Solar magnetic fields, Solar activity
Origins of X-Ray Line Emissions in Circinus X-1 at Very Low X-Ray Flux. Accretion conditions and morphologies of X-ray transients containing neutron stars are still poorly understood. Circinus X-1 is an enigmatic case where we observe X-ray flux changes covering four orders of magnitude. We observed Circinus X-1 several times at its very lowest X-ray flux using the high-energy transmission grating spectrometer on board the Chandra X-ray Observatory. At a flux of 1.8× {10}-11 erg cm-2 s-1 we observed a single 1.6 keV blackbody spectrum. The observed continuum luminosity of 1035 erg s-1 is about two orders of magnitude too low to explain the observed photoionized luminosity, suggesting a much more complex structure of the X-ray source that is partially or entirely obscured, as had been previously suggested. This affects most emissions from the accretion disk, including previously observed accretion-disk coronal line emissions. Instead, the strongest observed photoionized lines are blueshifted by about ∼400 km s-1, and we suggest that they originate in the ionized wind of a B5Ia supergiant companion, supporting a previous identification. The neutron star in Cir X-1 is very young and should have a high magnetic field. At the observed luminosity, the emission radius of the blackbody is small enough to be associated with the accretion hot spot as the X-ray-emitting region. The small emission radius then points to a field strength below 1012 G, which would be consistent with the observation of occasional type I X-ray bursts at high magnetic fields. We discuss Cir X-1 in the context of being a high-mass X-ray binary, with some emphasis on a possible Be-star X-ray binary nature.

Keywords: Neutron stars, High mass x-ray binary stars, Accretion, X-ray sources
Nearly Century-scale Variation of the Sun's Radius. The Kodaikanal Archive Program (India) is now available to the scientific community in digital form as daily digitized solar white light pictures, from 1923 to 2011. We present here the solar radius data, obtained after a painstaking effort to remove all effects that contribute to the error in their measurements (limb darkening, distortion of the objective lens, refraction, other instrumental effects, etc.). These data were analyzed to reveal any significant periodic variations, after applying a multi-taper method with red noise approximation and the Morlet wavelet transform analysis. After removing obvious periodic variations (such as solar rotation and Earth annual rotation), we found a possible cycle variation at 11.4 yr, quasi biennial oscillations at 1.5 and 3.8 yr, and Rieger-type periodicity at ≈159, 91, and 63 days. Another ≈ 7.5 yr periodicity (as a mean) resulting from two other main periodicities detected at 6.3-7.8 yr can be identified as an atmospheric component. The detrending data show, over a mean radius of 959.7" ± 0.5", a residual of less than ≈(-)1 mas over the time period of analysis: if not spurious, this estimate indicates a faint decline, but probably confirms more the constancy of the solar diameter during the considered ranging time, within instrumental and methodological limits. The Kodaikanal long quality observations contribute to international efforts to bring past solar data measurements to the community to further explore issues, for instance, those of the luminosity/radius properties that could be used to pinpoint the "seat of the solar cycle."

Keywords: Solar radius
Radioactive Heating Rate of r-process Elements and Macronova Light Curve. We study the heating rate of r-process nuclei and thermalization of decay products in neutron star merger ejecta and macronova (kilonova) light curves. Thermalization of charged decay products, I.e., electrons, α-particles, and fission fragments, is calculated according to their injection energy. The γ-ray thermalization processes are also properly calculated by taking the γ-ray spectrum of each decay into account. We show that the β-decay heating rate at later times approaches a power-law decline as ∝t-2.8, which agrees with the result of Waxman et al. We present a new analytic model to calculate macronova light curves, in which the density structure of the ejecta is accounted for. We demonstrate that the observed bolometric light curve and temperature evolution of the macronova associated with GW170817 are reproduced well by the β-decay heating rate with the solar r-process abundance pattern. We interpret the break in the observed bolometric light curve around a week as a result of the diffusion wave crossing a significant part of the ejecta rather than a thermalization break. We also show that the time-weighted integral of the bolometric light curve (Katz integral) is useful to provide an estimate of the total r-process mass from the observed data, which is independent of the highly uncertain radiative transfer. For the macronova in GW170817, the ejecta mass is robustly estimated as ≈0.05 M⊙ for Amin ≤ 72 and 85 ≤ Amin ≤ 130 with the solar r-process abundance pattern. The code for computation of the heating rate and light curve for given initial nuclear abundances is publicly available.

Keywords: Gravitational wave astronomy, R-process, Compact binary stars
The (Re)appearance of NGC 925 ULX-3, a New Transient ULX. We report the discovery of a third ULX in NGC 925 (ULX-3), detected in 2017 November by Chandra at a luminosity of LX = (7.8 ± 0.8) × 1039 erg s-1. Examination of archival data for NGC 925 reveals that ULX-3 was detected by Swift at a similarly high luminosity in 2011, as well as by XMM-Newton in 2017 January at a much lower luminosity of LX = (3.8 ± 0.5) × 1038 erg s-1. With an additional Chandra nondetection in 2005, this object demonstrates a high dynamic range of flux of factor ≳26. In its high-luminosity detections, ULX-3 exhibits a hard power-law spectrum with Γ = 1.6 ± 0.1, whereas the XMM-Newton detection is slightly softer, with Γ={1.8}-0.1+0.2, and is also well-fitted with a broadened disk model. The long-term light curve is sparsely covered and could be consistent either with the propeller effect or with a large-amplitude superorbital period, both of which are seen in ULXs, in particular those with neutron star accretors. Further systematic monitoring of ULX-3 will allow us to determine the mechanism by which ULX-3 undergoes its extreme variability and to better understand the accretion processes of ULXs.

Keywords: Accretion, Neutron stars, X-ray binary stars, Black holes, Light curves, X-ray transient sources
Global Simulations of Self-gravitating Magnetized Protoplanetary Disks. In the early stages of a protoplanetary disk, turbulence generated by gravitational instability (GI) should feature significantly in the disk's evolution. At the same time, the disk may be sufficiently ionized for magnetic fields to play some role in the dynamics. In this paper, we report on global three-dimensional magnetohydrodynamical simulations of a self-gravitating protoplanetary disk using the meshless finite mass Lagrangian technique. We confirm that GI spiral waves trigger a dynamo that amplifies an initial magnetic field to nearly thermal amplitudes (plasma β &lt; 10), an order of magnitude greater than that generated by the magnetorotational instability alone. We also determine the dynamo's nonlinear back reaction on the gravito-turbulent flow: the saturated state is substantially hotter, with an associated larger Toomre parameter and weaker, more "flocculent" spirals. But perhaps of greater import is the dynamo's boosting of accretion via a significant Maxwell stress; mass accretion is enhanced by factors of several relative to either pure GI or pure magnetorotational instability. Our simulations use ideal MHD, an admittedly poor approximation in protoplanetary disks, and thus, future studies should explore the full gamut of nonideal MHD. In preparation for that, we exhibit a small number of ohmic runs that reveal that the dynamo, if anything, is stronger in a nonideal environment. This work confirms that magnetic fields are a potentially critical ingredient in gravito-turbulent young disks, possibly controlling their evolution, especially via their enhancement of (potentially episodic) accretion.

Keywords: Magnetohydrodynamics, Gravitational instability, Protoplanetary disks
On the XUV Luminosity Evolution of TRAPPIST-1. We model the long-term X-ray and ultraviolet (XUV) luminosity of TRAPPIST-1 to constrain the evolving high-energy radiation environment experienced by its planetary system. Using a Markov Chain Monte Carlo (MCMC) method, we derive probabilistic constraints for TRAPPIST-1's stellar and XUV evolution that account for observational uncertainties, degeneracies between model parameters, and empirical data of low-mass stars. We constrain TRAPPIST-1's mass to m⋆ = 0.089 ± 0.001 M⊙ and find that its early XUV luminosity likely saturated at log10({L}XUV/{L}bol)=-{3.03}-0.12+0.23 . From the posterior distribution, we infer that there is a ∼40% chance that TRAPPIST-1 is still in the saturated phase today, suggesting that TRAPPIST-1 has maintained high activity and LXUV/Lbol ≈ 10-3 for several gigayears. TRAPPIST-1's planetary system therefore likely experienced a persistent and extreme XUV flux environment, potentially driving significant atmospheric erosion and volatile loss. The inner planets likely received XUV fluxes ∼103-104 times that of the modern Earth during TRAPPIST-1's ∼1 Gyr long pre-main-sequence phase. Deriving these constraints via MCMC is computationally nontrivial, so scaling our methods to constrain the XUV evolution of a larger number of M dwarfs that harbor terrestrial exoplanets would incur significant computational expenses. We demonstrate that approxposterior, an open source Python machine learning package for approximate Bayesian inference using Gaussian processes, accurately and efficiently replicates our analysis using 980 times less computational time and 1330 times fewer simulations than MCMC sampling using emcee. We find that approxposterior derives constraints with mean errors on the best-fit values and 1σ uncertainties of 0.61% and 5.5%, respectively, relative to emcee.

Keywords: Stellar luminosities, Stellar properties, Stellar activity, Exoplanet evolution, Stellar evolution
A New Approach to the Mass and Radius of Neutron Stars with Supernova Neutrinos. Neutron stars are formed in core-collapse supernova explosions, where a large number of neutrinos are emitted. In this paper, supernova neutrino light curves are computed for the cooling phase of protoneutron stars, which lasts a few minutes. In the numerical simulations, 90 models of the phenomenological equation of state with different incompressibilities, symmetry energies, and nucleon effective masses are employed for a comprehensive study. It is found that the cooling timescale is longer for a model with a larger neutron star mass and a smaller neutron star radius. Furthermore, a theoretical expression of the cooling timescale is presented as a function of the mass and radius and it is found to describe the numerical results faithfully. These findings suggest that diagnosing the mass and radius of a newly formed neutron star using its neutrino signal is possible.

Keywords: Neutron stars, Supernova neutrinos, Neutron star cores, Core-collapse supernovae, Neutrino astronomy, Nuclear astrophysics
The Role of the Parker Instability in Structuring the Interstellar Medium. The Parker instability, a Rayleigh-Taylor-like instability of thermal gas supported against gravity by magnetic fields and cosmic rays, is thought to be dynamically important for galaxy evolution, possibly promoting molecular cloud formation and the galactic dynamo. In previous work, we examined the effect of three different cosmic-ray transport models on the Parker instability: decoupled (γc = 0), locked to the thermal gas (γc = 4/3), and coupled to the gas with streaming by self-confinement. We expand on that work here by considering radiative cooling, a smooth gravitational potential, and simulations into the nonlinear regime. We determine that cosmic-ray transport away from compression points, whether by diffusion or streaming, is the largest driver of the instability. Heating due to cosmic-ray streaming is also destabilizing and especially affects the nonlinear regime. While cooling depressurizes the dense gas, streaming cosmic rays heat and inflate the diffuse extraplanar gas, greatly modifying the phase structure of the medium. In 3D, we find that the fastest growth favors short-wavelength modes in the horizontal direction perpendicular to the background magnetic field; this is imprinted on Faraday rotation measure maps that may be used to detect the Parker instability. The modifications to the Parker instability that we observe in this work have large implications for the structure and evolution of galaxies, and they highlight the major role that cosmic rays play in shaping their environments.

Keywords: Gravitational instability, Interstellar dynamics, Interstellar plasma, Interstellar magnetic fields, Interstellar medium, Cosmic rays