adsabs/SciX_UAT_keywords huggingface dataset:
Delivery of Gas onto the Circumplanetary Disk of Giant Planets: Planetary-mass Dependence of the Source Region of Accreting Gas and Mass Accretion Rate

Gas accretion onto the circumplanetary disks and the source region of accreting gas are important to reveal dust accretion that leads to satellite formation around giant planets. We performed local three-dimensional high-resolution hydrodynamic simulations of an isothermal and inviscid gas flow around a planet to investigate the planetary-mass dependence of the gas accretion bandwidth and gas accretion rate onto circumplanetary disks. We examined cases with various planetary masses corresponding to M p = 0.05-1M Jup at 5.2 au, where M Jup is the current Jovian mass. We found that the radial width of the gas accretion band is proportional to {M}_{{\rm{p}}}^{1/6}$ for the low-mass regime with M p ≲ 0.2M Jup while it is proportional to M p for the high-mass regime with M p ≳ 0.2M Jup. We found that the ratio of the mass accretion rate onto the circumplanetary disk to that into the Hill sphere is about 0.4 regardless of the planetary mass for the cases we examined. Combining our results with the gap model obtained from global hydrodynamic simulations, we derive a semi-analytical formula of mass accretion rate onto circumplanetary disks. We found that the mass dependence of our three-dimensional accretion rates is the same as the previously obtained two-dimensional case, although the qualitative behavior of accretion flow onto the circumplanetary disk is quite different between the two cases.

Keywords: galilean satellites; jovian satellites; planetary system formation; planet formation; planetary science
Properties of F Stars with Stable Radial Velocity Timeseries: A Useful Metric for Selecting Low-jitter F Stars

In a companion paper, we have conducted an in-depth analysis of radial velocity jitter of over 600 stars, examining the astrophysical origins including stellar granulation, oscillation, and magnetic activity. In this paper, we highlight a subsample of those stars, specifically the main sequence and "retired" F stars -- which we refer to as "MSRF" stars -- that show low levels of RV jitter (<10 m s-1). We describe the observational signatures of these stars that allow them to be identified in radial velocity planet programs, for instance, those performing follow-up of transiting planets discovered by TESS. We introduce a "jitter metric" that combines the two competing effects of RV jitter with age: activity and convection. Using thresholds in the jitter metric, we can select both "complete" and "pure" samples of low jitter F stars. We also provide recipes for identifying these stars using only Gaia colors and magnitudes. Finally, we describe a region in the Gaia color-magnitude diagram where low jitter F stars are most highly concentrated. By fitting a ninth-order polynomial to the Gaia main sequence, we use the height above the main sequence as a proxy for evolution, allowing for a crude selection of low jitter MSRF stars when activity measurements are otherwise unavailable.

Keywords: exoplanet detection methods; radial velocity
Probing the Interplay between Jets, Winds, and Multi-phase Gas in 11 Radio-quiet PG Quasars: A uGMRT-VLA Study

We present polarization-sensitive images from the Karl G. Jansky Very Large Array (VLA) at 5 GHz of 11 radio-quiet PG quasars. Based on the radio morphology, spectral index, and polarization properties from the VLA study, coupled with the findings of our previous 685 MHz uGMRT data, we find the presence of low-power jets on subarcsecond and arcsecond scales in nine sources; some show signatures of bent jets. The origin of radio emission remains unclear in the remaining two sources. Of the 11 sources, linear polarization is detected in four of them with fractional polarization ranging between 2% and 21%. In PG 1229+204, the inferred B-field direction is parallel to the local kiloparsec-scale jet direction. The inferred B-fields are transverse to the weak southward extension in PG 0934+013. For PG 0050+124 and PG 0923+129, the relationship between the B-field structure and radio outflow direction remains unclear. Localized or small-scale jet-medium interactions can be inferred across the sample based on the VLA jet kinetic power arguments and polarization data. These may have the potential as a feedback mechanism. We find that the radio properties do not show strong correlations with the star formation, [O III] and CO quantities published in the literature. The lack of evidence of AGN feedback on the global galaxy properties could be due to the relative timescales of AGN activity and those over which any impact might be taking place.

Keywords: radio quiet quasars; radio continuum emission; polarimetry
Exploiting Orbital Constraints from Optical Data to Detect Binary Gamma-Ray Pulsars

It is difficult to discover pulsars via their gamma-ray emission because current instruments typically detect fewer than one photon per million rotations. This creates a significant computing challenge for isolated pulsars, where the typical parameter search space spans wide ranges in four dimensions. It is even more demanding when the pulsar is in a binary system, where the orbital motion introduces several additional unknown parameters. Building on earlier work by Pletsch & Clark, we present optimal methods for such searches. These can also incorporate external constraints on the parameter space to be searched, for example, from optical observations of a presumed binary companion. The solution has two parts. The first is the construction of optimal search grids in parameter space via a parameter space metric, for initial semicoherent searches and subsequent fully coherent follow-ups. The second is a method to demodulate and detect the periodic pulsations. These methods have different sensitivity properties than traditional radio searches for binary pulsars and might unveil new populations of pulsars.

Keywords: gamma-ray sources; millisecond pulsars; binary pulsars; astronomy data analysis
Coexistence of Plasmoid and Kelvin-Helmholtz Instabilities in Collisionless Plasma Turbulence

The plasmoid formation in collisionless plasmas, where magnetic reconnection within turbulence may take place driven by the electron inertia, is analyzed. We find a complex situation in which, due to the presence of strong velocity shears, the typical plasmoid formation, observed to influence the energy cascade in the magnetohydrodynamic context, has to coexist with the Kelvin-Helmholtz (KH) instability. We find that the current density layers may undergo the plasmoid or the KH instability depending on the local values of the magnetic and velocity fields. The competition among these instabilities affects not only the evolution of the current sheets, that may generate plasmoid chains or KH-driven vortices, but also the energy cascade, that is different for the magnetic and kinetic spectra.

Keywords: plasma astrophysics; plasma physics; magnetic fields; magnetohydrodynamics
The Interior and Atmosphere of the Habitable-zone Exoplanet K2-18b

Exoplanets orbiting M-dwarfs present a valuable opportunity for their detection and atmospheric characterization. This is evident from recent inferences of H2O in such atmospheres, including that of the habitable-zone exoplanet K2-18b. With a bulk density between Earth and Neptune, K2-18b may be expected to possess a H/He envelope. However, the extent of such an envelope and the thermodynamic conditions of the interior remain unexplored. In the present work, we investigate the atmospheric and interior properties of K2-18b based on its bulk properties and its atmospheric transmission spectrum. We constrain the atmosphere to be H2-rich with a H2O volume mixing ratio of 0.02%-14.8%, consistent with previous studies, and find a depletion of CH4 and NH3, indicating chemical disequilibrium. We do not conclusively detect clouds/hazes in the observable atmosphere. We use the bulk parameters and retrieved atmospheric properties to constrain the internal structure and thermodynamic conditions in the planet. The constraints on the interior allow multiple scenarios between rocky worlds with massive H/He envelopes and water worlds with thin envelopes. We constrain the mass fraction of the H/He envelope to be ≲6%; spanning ≲10-5 for a predominantly water world to ∼6% for a pure iron interior. The thermodynamic conditions at the surface of the H2O layer range from the supercritical to liquid phases, with a range of solutions allowing for habitable conditions on K2-18b. Our results demonstrate that the potential for habitable conditions is not necessarily restricted to Earth-like rocky exoplanets.

Keywords: exoplanet atmospheres; planetary interior; exoplanet atmospheric composition; exoplanet surface characteristics; habitable planets; habitable zone
A New Census of the 0.2 < z < 3.0 Universe. II. The Star-forming Sequence

We use the panchromatic spectral energy distribution (SED)-fitting code Prospector to measure the galaxy logM*-logSFR relationship (the star-forming sequence) across 0.2 < z < 3.0 using the COSMOS-2015 and 3D-HST UV-IR photometric catalogs. We demonstrate that the chosen method of identifying star-forming galaxies introduces a systematic uncertainty in the inferred normalization and width of the star-forming sequence, peaking for massive galaxies at ~0.5 and ~0.2 dex, respectively. To avoid this systematic, we instead parameterize the density of the full galaxy population in the logM*-logSFR-redshift plane using a flexible neural network known as a normalizing flow. The resulting star-forming sequence has a low-mass slope near unity and a much flatter slope at higher masses, with a normalization 0.2-0.5 dex lower than typical inferences in the literature. We show this difference is due to the sophistication of the Prospector stellar populations modeling: the nonparametric star formation histories naturally produce higher masses while the combination of individualized metallicity, dust, and star formation history constraints produce lower star formation rates (SFRs) than typical UV+IR formulae. We introduce a simple formalism to understand the difference between SFRs inferred from SED fitting and standard template-based approaches such as UV+IR SFRs. Finally, we demonstrate the inferred star-forming sequence is consistent with predictions from theoretical models of galaxy formation, resolving a long-standing ~ 0.2-0.5 dex offset with observations at 0.5 < z < 3. The fully trained normalizing flow including a nonparametric description of $\rho (\mathrm{log}{M}^{* },\mathrm{logSFR},z)$ is available online 20 20 https://github.com/jrleja/sfs_leja_trained_flow to facilitate straightforward comparisons with future work.

Keywords: galaxy formation; galaxy photometry; galaxy masses; star formation
Combining Planck and SPT Cluster Catalogs: Cosmological Analysis and Impact on the Planck Scaling Relation Calibration

We provide the first combined cosmological analysis of the South Pole Telescope (SPT) and Planck cluster catalogs. The aim is to provide an independent calibration for Planck scaling relations, exploiting the cosmological constraining power of the SPT-SZ cluster catalog and its dedicated weak lensing (WL) and X-ray follow-up observations. We build a new version of the Planck cluster likelihood. In the νΛ CDM scenario, focusing on the mass slope and mass bias of Planck scaling relations, we find ${\alpha }_{\mathrm{SZ}}={1.49}_{-0.10}^{+0.07}$ and ${\left(1-b\right)}_{\mathrm{SZ}}={0.69}_{-0.14}^{+0.07}$ , respectively. The results for the mass slope show a ~4 σ departure from the self-similar evolution, α SZ ~ 1.8. This shift is mainly driven by the matter density value preferred by SPT data, Ω m = 0.30 ± 0.03, lower than the one obtained by Planck data alone, ${{\rm{\Omega }}}_{m}={0.37}_{-0.06}^{+0.02}$ . The mass bias constraints are consistent both with outcomes of hydrodynamical simulations and external WL calibrations, (1 - b) ~ 0.8, and with results required by the Planck cosmic microwave background cosmology, (1 - b) ~ 0.6. From this analysis, we obtain a new catalog of Planck cluster masses M 500. We estimate the ratio between the published Planck M SZ masses and our derived masses M 500, as a "measured mass bias," ${\left(1-b\right)}_{M}$ . We analyze the mass, redshift, and detection noise dependence of ${\left(1-b\right)}_{M}$ , finding an increasing trend toward high redshift and low mass. These results mimic the effect of departure from self-similarity in cluster evolution, showing different dependencies for the low-mass, high-mass, low-z, and high-z regimes.

Keywords: cosmology; large-scale structure of the universe; galaxy cluster counts
MOCMC: Method of Characteristics Moment Closure, a Numerical Method for Covariant Radiation Magnetohydrodynamics

We present a conservative numerical method for radiation magnetohydrodynamics with frequency-dependent full transport in stationary spacetimes. This method is stable and accurate for both large and small optical depths and radiation pressures. The radiation stress-energy tensor is evolved in flux-conservative form, and closed with a swarm of samples that each transport a multigroup representation of the invariant specific intensity along a null geodesic. In each zone, the enclosed samples are used to efficiently construct a Delaunay triangulation of the unit sphere in the comoving frame, which in turn is used to calculate the Eddington tensor, average source terms, and adaptively refine the sample swarm. Radiation four-forces are evaluated in the moment sector in a semi-implicit fashion. The radiative transfer equation is solved in invariant form deterministically for each sample. Since each sample carries a discrete representation of the full spectrum, the cost of evaluating the transport operator is independent of the number of frequency groups, representing a significant reduction of algorithmic complexity for transport in frequency-dependent problems. The major approximation we make in this work is performing scattering in an angle-averaged way. Local adaptivity in samples also makes this scheme more amenable to nonuniform meshes than a traditional Monte Carlo method. We describe the method and present results on a suite of test problems. We find that Method of Characteristics Moment Closure converges at least as ∼N-1, rather than the canonical Monte Carlo N-1/2, where N is the number of samples per zone.

Keywords: high energy astrophysics; black holes; relativistic fluid dynamics; compact radiation sources; computational methods
Exploring Tidal Obliquity Variations with SMERCURY-T

We introduce our new code, SMERCURY-T, which is based on existing codes SMERCURY and Mercury-T. The result is a mixed-variable symplectic N-body integrator that can compute the orbital and spin evolution of a planet within a multiplanet system under the influence of tidal spin torques from its star. We validate our implementation by comparing our experimental results to that of a secular model. As we demonstrate in a series of experiments, SMERCURY-T allows for the study of secular spin-orbit resonance crossings and captures for planets within complex multiplanet systems. These processes can drive a planet's spin state to evolve along vastly different pathways on its road toward tidal equilibrium, as tidal spin torques dampen the planet's spin rate and evolve its obliquity. Additionally, we show the results of a scenario that exemplifies the crossing of a chaotic region that exists as the overlap of two spin-orbit resonances. The test planet experiences violent and chaotic swings in its obliquity until its eventual escape from resonance as it tidally evolves. All of these processes are and have been important over the obliquity evolution of many bodies within the solar system and beyond and have implications for planetary climate and habitability. SMERCURY-T is a powerful and versatile tool that allows for further study of these phenomena.

Keywords: astrobiology; computational astronomy; computational methods; exoplanet dynamics; exoplanet tides; astronomy software; habitable planets
Evolution of the Water Snow Line in Magnetically Accreting Protoplanetary Disks

The low water content of the terrestrial planets in the solar system suggests that the protoplanets formed within the water snow line. Accurate prediction of the snow line location moving with time provides a clue to constraining the formation process of the planets. In this paper, we investigate the migration of the snow line in protoplanetary disks whose accretion is controlled by laminar magnetic fields, which have been proposed by various nonideal magnetohydrodynamic (MHD) simulations. We propose an empirical model of the disk temperature based on our nonideal MHD simulations, which show that the accretion heating is significantly less efficient than that in turbulent disks, and calculate the snow line location over time. We find that the snow line in magnetically accreting laminar disks moves inside the current Earth's orbit within 1 Myr after star formation, whereas the time for the conventional turbulent disk is much longer than 1 Myr. This result suggests that either the rocky protoplanets formed in such an early phase of the disk evolution, or the protoplanets moved outward to the current orbits after they formed close to the protosun.

Keywords: protoplanetary disks; magnetohydrodynamics; planet formation; solar system terrestrial planets
BASS. XXVIII. Near-infrared Data Release 2: High-ionization and Broad Lines in Active Galactic Nuclei

We present the BAT AGN Spectroscopic Survey (BASS) Near-infrared Data Release 2 (DR2), a study of 168 nearby ( , z < 0.6) active galactic nuclei (AGN) from the all-sky Swift Burst Array Telescope X-ray survey observed with the Very Large Telescope (VLT)/X-shooter in the near-infrared (NIR; 0.8–2.4 μm). We find that 49/109 (45%) Seyfert 2 and 35/58 (60%) Seyfert 1 galaxies observed with VLT/X-shooter show at least one NIR high-ionization coronal line (CL; ionization potential χ > 100 eV). Comparing the emission of the [Si VI] λ1.9640 CL with the X-ray emission for the DR2 AGN, we find a significantly tighter correlation, with a lower scatter (0.37 dex) than that for the optical [O III] λ5007 line (0.71 dex). We do not find any correlation between CL emission and the X-ray photon index Γ. We find a clear trend of line blueshifts with increasing ionization potential in several CLs, such as [Si VI] λ1.9640, [Si X] λ1.4300, [S VIII] λ0.9915, and [S IX] λ1.2520, indicating the radial structure of the CL region. Finally, we find a strong underestimation bias in black hole mass measurements of Sy 1.9 using broad Hα due to the presence of significant dust obscuration. In contrast, the broad Paα and Paβ emission lines are in agreement with the M–σ relation. Based on the combined DR1 and DR2 X-shooter sample, the NIR BASS sample now comprises 266 AGN with rest-frame NIR spectroscopic observations, the largest set assembled to date. * Based on observations collected under programs 086.B-0135(A), 089.B-0951(A), 090.A-0830(A), 091.B-0900(B), 093.A-0766(A), 098.A-0635(B), 099.A-0403(B), 0101.A-0765(A), and 0102.A-0433(A) with X-shooter at the Very Large Telescope of the Paranal Observatory in Chile, operated by the European Southern Observatory.

Keywords: active galactic nuclei
A Spectroscopic Thermometer: Individual Vibrational Band Spectroscopy with the Example of OH in the Atmosphere of WASP-33b

Individual vibrational band spectroscopy presents an opportunity to examine exoplanet atmospheres in detail, by distinguishing where the vibrational state populations of molecules differ from the current assumption of a Boltzmann distribution. Here, retrieving vibrational bands of OH in exoplanet atmospheres is explored using the hot Jupiter WASP-33b as an example. We simulate low-resolution spectroscopic data for observations with the JWST's NIRSpec instrument and use high-resolution observational data obtained from the Subaru InfraRed Doppler instrument (IRD). Vibrational band-specific OH cross-section sets are constructed and used in retrievals on the (simulated) low- and (real) high-resolution data. Low-resolution observations are simulated for two WASP-33b emission scenarios: under the assumption of local thermal equilibrium (LTE) and with a toy non-LTE model for vibrational excitation of selected bands. We show that mixing ratios for individual bands can be retrieved with sufficient precision to allow the vibrational population distributions of the forward models to be reconstructed. A fit for the Boltzmann distribution in the LTE case shows that the vibrational temperature is recoverable in this manner. For high-resolution, cross-correlation applications, we apply the individual vibrational band analysis to an IRD spectrum of WASP-33b, applying an "unpeeling" technique. Individual detection significances for the two strongest bands are shown to be in line with Boltzmann-distributed vibrational state populations, consistent with the effective temperature of the WASP-33b atmosphere reported previously. We show the viability of this approach for analyzing the individual vibrational state populations behind observed and simulated spectra, including reconstructing state population distributions.

Keywords: astronomy data modeling; exoplanet atmospheres; exoplanet atmospheric composition; hot jupiters; high resolution spectroscopy; near infrared astronomy
Cosmological Evolution of the Formation Rate of Short Gamma-Ray Bursts with and without Extended Emission

Originating from neutron starneutron star or neutron starblack hole mergers, short gamma-ray bursts (SGRBs) are the first electromagnetic emitters associated with gravitational waves (GWs). This association makes the determination of SGRB formation rate (FR) a critical issue. We determine the true SGRB FR and its relation to the cosmic star formation rate (SFR). This can help in determining the expected GW rate involving small mass mergers. We present nonparametric methods for the determination of the evolutions of the luminosity function (LF) and the FR using SGRBs observed by Swift, without any assumptions. These are powerful tools for small samples, such as our sample of 68 SGRBs. We combine SGRBs with and without extended emission (SEE), assuming that both descend from the same progenitor. To overcome the incompleteness introduced by redshift measurements we use the KolmogorovSmirnov (KS) test to find flux thresholds yielding a sample of sources with a redshift drawn from the parent sample including all sources. Using two subsamples of SGRBs with flux limits of 4.57 107 and 2.15 107 erg cm2 s1 with respective KS p (1, 0.9), we find a 3 evidence for luminosity evolution (LE), a broken power-law LF with significant steepening at L 1050 erg s1, and an FR evolution that decreases monotonically with redshift (independent of LE and the thresholds). Thus, SGRBs may have been more luminous in the past with an FR delayed relative to the SFR as expected in the merger scenario.

Keywords: gamma-ray bursts