Sazuna/UAT_keywords huggingface dataset:
Streaming Torque in Dust–Gas Coupled Protoplanetary Disks. We investigate the migration of low-mass protoplanets embedded in dust–gas coupled protoplanetary disks. Linear calculations are performed with respect to the Nakagawa–Sekiya–Hayashi (NSH) equilibrium within a shearing sheet. We find that the dusty quasi-drift mode dominates the dynamical behaviors in close proximity to the protoplanet. This mode exhibits an extremely short radial wavelength, characterized by a dispersion relation of  ω∼=fgWsṡk . The emergence of this mode leads to a wake with a short radial length scale ahead of protoplanets, contributing to a positive torque, termed as "streaming torque" (ST). Furthermore, both Lindblad torque and corotation torque are affected by the NSH velocity. The total torque and planetary migration are contingent upon the coupling strength between dust and gas. In most scenarios, ST predominates, inducing outward migration for planets, thereby addressing the issue of rapid inward migration in their formation paradigm.

Keywords: Planetary system formation, Planetary-disk interactions, Protoplanetary disks, Hydrodynamics
Source of Drift-dispersed Electrons in Martian Crustal Magnetic Fields. Mars lacks a global intrinsic dipole field but possesses localized crustal fields, making it unique in the solar system. Recent observations revealed that electrons can be injected into the crustal fields, and exhibit drift-dispersed bursts due to the magnetic drift motion, which are characterized by increases or decreases in energy over time in the energy spectrum. However, the source of the drift-dispersed electrons and the mechanism of their injection into the crustal fields remains unclear. Here, by leveraging data from the Mars Atmosphere and Volatile EvolutioN mission, along with test-particle simulations, we reveal that the source of dispersed electrons is the precipitating electrons injected into the crustal fields via open field lines. These electrons display as dispersionless bursts near the source location, and as dispersed bursts as they drift away from the source. Thus, the dispersed electrons represent a later stage in the evolution of dispersionless electrons. This evolutionary process closely mirrors that observed within Earth's dipole field, affirming that the crustal fields function similarly to a mini-magnetosphere.

Keywords: Mars, Solar wind, Magnetic fields
The Response of Broadband Kilometric Radiation to Compressions of the Jovian Magnetosphere. In the planetary magnetosphere, plasma waves act as the medium for particles to transfer energy. Jupiter is the largest planet in our solar system, and the giant magnetosphere is full of energetic particles, producing intense radio emissions. When interplanetary shocks in the solar wind interact with the Jovian magnetosphere, magnetospheric conditions change, and the characteristics of Jovian radio emissions show distinct variations accordingly. This study focuses on the morphological characteristics of Jovian broadband kilometric radiation (bKOM) under different magnetospheric conditions, i.e., relaxed and compressed. Using observations from Juno, both the frequency range and duration of Jovian bKOM radio emissions are studied, and we compare their variations during compressed and relaxed magnetospheric conditions. Our results show that under compressed magnetospheric conditions, the observed frequency range of Jovian bKOM generally exceeded 100 kHz, and their duration extended from 0 to 3 hr during uncompressed conditions to about 4–9 hr. The distinct features of radio emissions under different magnetospheric conditions imply that solar wind conditions have important influences on Jovian radio emissions, and thus the radio emissions can be used as a diagnostic tool of solar wind interaction with the Jovian magnetosphere.

Keywords: Planetary magnetospheres, Magnetospheric radio emissions, Jupiter
The Age-dependent Vertical Actions of Young Stars in the Galaxy. Stars in the Galactic disk are born on cold, nearly circular orbits with small vertical excursions. After their birth, their orbits evolve, driven by small- or large-scale perturbations in the Galactic disk's gravitational potential. Here, we study the vertical motions of young stars over their first few orbital periods, using a sample of OBA stars from Gaia E/DR3, which includes radial velocities and ages τ from LAMOST. We construct a parametric model for the time evolution of the stellar orbits' mean vertical actions J  z  as a function of Galactocentric radius, R GC. Accounting for data uncertainties, we use Markov Chain Monte Carlo analysis in annuli of Galactocentric radius (R GC) to constrain the model parameters. Our best-fit model shows a remarkably linear increase of vertical actions with age across all Galactocentric radii examined. Orbital heating by random scattering could offer a straightforward interpretation for this trend. However, various other dynamical aspects of the Galactic disk, such as stars being born in a warped disk, might offer alternative explanations that could be tested in the future.

Keywords: Milky Way Galaxy physics, Milky Way disk, Galaxy evolution, Milky Way evolution, Galaxy processes
FRESCO: The Paschen-α Star-forming Sequence at Cosmic Noon. We present results from the JWST First Reionization Epoch Spectroscopically Complete Observations survey on the star-forming sequence (SFS) of galaxies at 1.0 &lt; z &lt; 1.7, around the peak of the cosmic star formation history. Star formation rates (SFRs) are measured from the redshifted, relatively dust-insensitive Paschen-α emission line, and stellar mass measurements include the F444W (4.4 μm; rest-frame H) band. We find SFRs of galaxies with log(M */M ⊙) &gt; 9.5 that are lower than found in many earlier studies by up to 0.6 dex, but in good agreement with recent results obtained with the Prospector fitting framework. The difference (log(SFR(Paα)-SFR(Prospector)) is ‑0.09 ± 0.04 dex at 1010‑11 M ⊙. We also measure the empirical relation between Paschen-α luminosity and rest-frame H-band magnitude and find that the scatter is only 0.04 dex lower than that of the SFR–M* relation and is much lower than the systematic differences among relations in the literature due to various methods of converting observed measurements to physical properties. We additionally identify examples of sources—that, with standard cutoffs via the UVJ diagram, would be deemed quiescent—with significant (log(sSFR)&gt; ‑11 yr‑1), typically extended, Paschen-α emission. Our results may be indicative of the potential unification of methods used to derive the SFS with careful selection of star-forming galaxies and independent SFR and stellar mass indicators.

Keywords: Star formation, Galaxy evolution, Galaxy properties, Scaling relations
Inferring Host-galaxy Properties of LIGO–Virgo–KAGRA's Black Holes. Observations of gravitational waves from binary black hole (BBH) mergers have measured the redshift evolution of the BBH merger rate. The number density of galaxies in the Universe evolves differently with redshift based on their physical properties, such as their stellar masses and star formation rates. In this work we show that the measured population-level redshift distribution of BBHs sheds light on the properties of their probable host galaxies. We first assume that the hosts of BBHs can be described by a mixture model of galaxies weighted by stellar mass or star formation rate, and find that we can place upper limits on the fraction of mergers coming from a stellar-mass-weighted sample of galaxies. We then constrain the parameters of a physically motivated power-law delay-time distribution using GWTC-3 data, and self-consistently track galaxies in the UNIVERSEMACHINE simulations with this delay-time model to infer the probable host galaxies of BBHs over a range of redshifts. We find that the inferred host galaxy distribution at redshift z = 0.21 has a median star formation rate ∼ 0.9 M ⊙ yr‑1 and a median stellar mass of ∼1.9 × 1010 M ⊙. We also provide distributions for the mean stellar age, halo mass, halo radius, peculiar velocity, and large-scale bias associated with the host galaxies, as well as their absolute magnitudes in the B and Ks bands. Our results can be used to design optimal electromagnetic follow-up strategies for BBHs, and also to aid the measurement of cosmological parameters using the statistical dark-siren method.

Keywords: Gravitational wave astronomy
GRB 191221B: The Two-component Jet with Forward and Reverse Shock. The afterglows of gamma-ray bursts are believed to have originated from a relativistic jet, which is driven by the merger of compact binary objects or the core collapse of massive stars. Some of their jets may consist of two components: a faster (but narrower) jet and a slower (but wider) jet. The light curves produced by the interaction between the two-component jet and the surrounding medium typically exhibit a chromatic break in multiple bands. For GRB 191221B, the optical light curve of the afterglow exhibits a plateau from 33 to 143 s, followed by a steeper decay that is consistent with the characteristics of reverse shock from an arbitrarily magnetized ejecta. The flattening at ∼10 ks exhibits chromaticity relative to the X-ray afterglow. We propose that the two-component jet scenario can explain this observational result: For the X-ray afterglow, the narrow jet forward shock is dominated until ∼10 ks, and then both the narrow and wide components contribute comparable flux from the forward shock. For the optical afterglow, the first 2 ks is dominated by the narrow jet reverse shock emission (the plateau from 33 to 143 s is due to the jet being magnetized). Between 2 and 10 ks, the forward shock of the narrow jet dominates the optical afterglow, then transitions to wide component forward shock dominance, causing a chromatic plateau. For radio afterglow, the data are only presented after 105 s, which is dominated by the wide jet forward shock emission.

Keywords: Gamma-ray bursts, Relativistic jets
Are WASP-107-like Systems Consistent with High-eccentricity Migration?. WASP-107 b seems to be a poster child of the long-suspected high-eccentricity migration scenario. It is on a 5.7 day, polar orbit. The planet is Jupiter-like in radius but Neptune-like in mass with exceptionally low density. WASP-107 c is on a 1100 day, e = 0.28 orbit with at least Saturn mass. Planet b may still have a residual eccentricity of 0.06 ± 0.04: the ongoing tidal dissipation leads to the observed internally heated atmosphere and hydrodynamic atmospheric erosion. We present a population synthesis study coupling octupole Lidov–Kozai oscillations with various short-range forces, while simultaneously accounting for the radius inflation and tidal disruption of the planet. We find that a high-eccentricity migration scenario can successfully explain nearly all observed system properties. Our simulations further suggest that the initial location of WASP-107 b at the onset of migration is likely within the snowline (&lt;0.5 au). More distant initial orbits usually lead to tidal disruption or orbit crossing. WASP-107 b most likely lost no more than 20% of its mass during the high-eccentricity migration, i.e., it did not form as a Jupiter-mass object. More vigorous tidally induced mass loss leads to disruption of the planet during migration. We predict that the current-day mutual inclination between the planets b and c is substantial: at least 25°–55°, which may be tested with future Gaia astrometric observations. Knowing the current-day mutual inclination may further constrain the initial orbit of planet b. We suggest that the proposed high-eccentricity migration scenario of WASP-107 may be applicable to HAT-P-11, GJ-3470, HAT-P-18, and GJ-436, which have similar orbital architectures.

Keywords: Exoplanet migration, Hot Jupiters, Exoplanet astronomy, Exoplanet tides, Exoplanet formation
The Contribution of Solar Magnetic Regions to the Residual Meridional and Zonal Flows. We estimate the contributions to the solar-cycle variation of solar meridional and zonal flows near the surface expected solely from local magnetic regions. Maps of flows near magnetic regions are obtained using helioseismic holography and averaged over ensembles of such regions with similar magnetic flux. These averaged flows are assigned to the positions and times of all magnetic regions identified from daily magnetograms over an 11 yr period. Residuals are obtained after averaging both meridional and zonal-flow components over longitude for each Carrington rotation and subtracting the temporal mean at each latitude. Results indicate that magnetic regions produce solar-cycle variations of both components in the active latitude range with peak amplitudes of about 1 m s‑1, which represents only a fraction of the known variations in either the residual zonal or meridional flow with amplitudes around 3 and 5 m s‑1, respectively. Thus it is unlikely that active regions, and compact magnetic concentrations in general, are the primary source of the 11 yr variation in these global flows. A threshold magnetic flux of 5 × 1020 Mx, below which no significant flows are observed, is identified as a check on the completeness of the set of magnetic regions. We also find that inflows around most magnetic regions are confined to within 10°–12° of their centers, in contrast with recent evidence of more extended inflows.

Keywords: Solar cycle, Solar active region velocity fields, Solar active region magnetic fields, Solar rotation, Solar active regions, Solar meridional circulation
Aligning Planet-hosting Binaries via Dissipative Precession in Circumstellar Disks. Recent observations have demonstrated that some subsets of even moderately wide-separation planet-hosting binaries are preferentially configured such that planetary and binary orbits appear to lie within the same plane. In this work, we explore dissipation during the protoplanetary disk phase, induced by disk warping as the system is forced into nodal recession by an inclined binary companion as a possible avenue of achieving orbit–orbit alignment. We analytically model the coupled evolution of the disk angular momentum vector and stellar spin vector under the influence of a distant binary companion. We find that a population of systems with random initial orientations can appear detectably more aligned after undergoing dissipative precession, and that this process can simultaneously produce an obliquity distribution that is consistent with observations. While dissipative precession proceeds efficiently in close binaries, favorable system properties (e.g., r out ≳ 100 au, α ≳ 0.05, and/or M  b /M * ≳ 1) are required to reproduce observed alignment trends at wider binary separations a b ≳ 450 au. Our framework further predicts that circum-primary planets in systems with high stellar mass ratios should be preferentially less aligned than planets in equal mass stellar binary systems. We discover tentative evidence for this trend in Gaia DR3 and Transiting Exoplanet Survey Satellite data. Our findings suggest that dissipative precession may play a significant role in sculpting orbital configurations in a subset of moderately wide planet-hosting binaries, but is likely not solely responsible for their observed population-level alignment.

Keywords: Exoplanet dynamics, Binary stars, Exoplanets, Planetary alignment, Exoplanet systems, Star-planet interactions
Gamma-Ray Bursts Observed by the Transiting Exoplanet Survey Satellite: Prompt Optical Counterparts and Afterglows of Swift-XRT-localized Gamma-Ray Bursts. Very few detections have been made of optical flashes contemporaneous with prompt high-energy emission from a gamma-ray burst (GRB). In this work, we present and analyze light curves of GRB-associated optical flashes and afterglows from the Transiting Exoplanet Survey Satellite (TESS). Our sample consists of eight GRBs with arcsecond-level localizations from the X-Ray Telescope on board the Neil Gehrels Swift Observatory (Swift). For each burst, we characterize the prompt optical emission and any observed afterglow, and constrain physical parameters for four of these bursts using their TESS light curves. This work also presents a straightforward method to correct for TESS's cosmic-ray mitigation strategy on 20 s timescales, which allows us to estimate the "true" brightness of optical flashes associated with prompt GRB emission. We also highlight TESS's continuous wide-field monitoring capability, which provides an efficient means of identifying optical emission from GRBs and characterizing early time afterglow light curves. Based on empirical detection rates from Swift and the Fermi Gamma-ray Space Telescope, up to 10 GRBs per year may fall within the contemporaneous TESS field of view.

Keywords: Gamma-ray bursts, Transient sources
First JVLA Radio Observation on PDS 70. PDS 70 is a protoplanetary system that hosts two actively accreting gas giants, namely, PDS 70b and PDS 70 c. The system has a ∼60–100 au dusty ring that has been resolved by the Atacama Large Millimeter/Submillimeter Array (ALMA), along with circumplanetary disks around the two gas giants. Here, we report the first Karl G. Jansky Very Large Array (JVLA) Q- (40–48 GHz), Ka- (29–37 GHz), K- (18–26 GHz), and X- (8–12 GHz) bands' continuum observations, and the complementary ALMA Bands 3 (∼98 GHz) and 4 (∼145 GHz) observations towards PDS 70. The dusty ring appears azimuthally asymmetric in our ALMA images. We obtained firm detections at Ka and K bands without spatially resolving the source; we obtained a marginal detection at Q band, and no detection at X band. The spectral indices (α) are 5 ± 1 at 33–44 GHz and 0.6 ± 0.2 at 22–33 GHz. At 10–22 GHz, the conservative lower limit of α is 1.7. The 33–44 GHz flux density is likely dominated by the optically thin thermal emission of grown dust with ≳1 mm maximum grain sizes, which may be associated with the azimuthally asymmetric substructure induced by planet–disk interaction. Since PDS 70 was not detected at X band, we found it hard to explain the low spectral index at 22–33 GHz only with free–free emission. Hence, we attribute the dominant emission at 22–33 GHz to the emission of spinning nano-meter-sized dust particles, while free–free emission may partly contribute to emission at this frequency range. In some protoplanetary disks, the emission of spinning nano-meter-sized dust particles may resemble the 20–50 GHz excess in the spectra of millimeter-sized dust. The finding of strong continuum emission of spinning nano-meter-sized particles can complicate the procedure of constraining the properties of grown dust. Future high resolution, multifrequency JVLA/Next Generation Very Large Array and Square Kilometer Array observations may shed light on this issue.

Keywords: Circumstellar dust, Protoplanetary disks, Planet formation, Pre-main sequence
Thermal Properties of Current Sheet Plasmas in Solar Flares. The current sheet is an essential feature in solar flares and is the primary site for magnetic reconnection and energy release. Imaging observations feature a long linear structure above the candle-flame-shaped flare loops, which resembles the standard flare model with the current sheet viewed edge-on. We investigate the thermal properties of plasmas surrounding the linear sheet during flares, using EUV observations from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. The differential emission measure analyses show evidence of high temperatures in the plasma sheets (PSs), containing hot emissions from only a narrow temperature range, suggestive of an isothermal feature. The sheet temperature remains constant at different heights above the flare arcade, peaking at around  logT  = 7.0─7.1; while the well-studied 2017 September 10 X8.2 flare serves as an exception in that the temperature decreases with increasing height and peaks higher ( logT  = 7.25) during the gradual phase. Most PS cases also hold similar emission measures and thicknesses; while the PS emissions drop exponentially above the flare arcade, the sheet thicknesses show no significant height association as for all the measurements. The characteristics of isothermal and steady temperature suggest balanced heating and cooling processes along the current sheet; in particular, additional heating may exist to compensate for the conductive and radiative cooling away from the reconnection site. Our results suggest a steady and uniform sheet structure in the macroscopic scale that results from flare reconnection.

Keywords: Solar flares, Solar magnetic reconnection, Solar extreme ultraviolet emission, Solar corona, Solar coronal mass ejections
A Comparative Simulation Study of Hot and Ultrahot Jupiter Atmospheres Using Different Ground-based High-resolution Spectrographs with Cross-correlation Spectroscopy. In the era of state-of-the-art space-borne telescopes, high-resolution ground-based observation has emerged as a crucial method for characterizing exoplanets, providing essential insights into their atmospheric compositions. In the optical and near-infrared regions, high-resolution spectroscopy has been powerful for hot Jupiters (HJs) and ultrahot Jupiters (UHJs) during their primary transits, as it can probe molecules with better sensitivity. Here, we focus on a comparative simulation study of WASP-76 b (UHJ) and WASP-77 A b (HJ) for different numbers of transits, utilizing three ground-based spectrographs, GIANO-B (Telescopio Nazionale Galileo), CARMENES (Centro Astronomico Hispano Alemán), and ANDES (European Extremely Large Telescope or E-ELT), with varying instrumental parameters, spectral coverages, and resolutions. We aim to evaluate the feasibility of using the upcoming ground-based E-ELT to probe molecules from planet atmospheres and to show how it surpasses other ground-based observatories in terms of detectability. With the 1D model petitCODE, we have self-consistently simulated the atmospheric pressure–temperature profiles, which are subsequently integrated into the 1D chemical kinetics model, VULCAN, to evolve the atmospheric chemistry. High-resolution spectra are obtained by performing line-by-line radiative transfer using petitRADTRANS. Finally, we use the resulting spectra to assess the detectability ( σdet ) of molecular bands, employing the ground-based noise simulator SPECTR. Utilizing cross-correlation spectroscopy, we have successfully demonstrated the robust consistency between our simulation study and real-time observations for both planets. ANDES excels overall in molecular detection, due to its enhanced instrumental architecture, reinforcing E-ELT's importance for studying exoplanet atmospheres. Additionally, our theoretical simulations predict the detection of CO, NH3, and H2S in the WASP-76 b atmosphere with  σdet  &gt; 3.

Keywords: High resolution spectroscopy, Exoplanet atmospheric composition , Hot Jupiters, Extrasolar gaseous planets, Spectroscopy, Exoplanet atmospheres