Sazuna/UAT_keywords huggingface dataset:
Origin and Extent of the Opacity Challenge for Atmospheric Retrievals of WASP-39 b. As the James Webb Space Telescope (JWST) came online last summer, we entered a new era of astronomy. This new era is supported by data products of unprecedented information content that require novel reduction and analysis techniques. Recently, Niraula et al. (N22) highlighted the need for upgraded opacity models to prevent facing a model-driven accuracy wall when interpreting exoplanet transmission spectra. Here, we follow the same approach as N22 to explore the sensitivity of inferences on the atmospheric properties of WASP-39 b to the opacity models used. We find that the retrieval of the main atmospheric properties from this first JWST exoplanet spectrum is mostly unaffected by the current state of the community's opacity models. Abundances of strong opacity sources like water and carbon dioxide are reliably constrained within ~0.30 dex, beyond the 0.50 dex accuracy wall reported in N22. Assuming the completeness and accuracy of line lists, N22's accuracy wall is primarily driven by model uncertainties on broadening coefficients and far-wing behaviors, which we find to have marginal consequences for interpreting the transmission spectra of large, hot, high-metallicity atmospheres such as WASP-39 b, in opposition to emission spectra and climate modeling, which depend on deeper parts of a planetary atmosphere. The origin of the opacity challenge in the retrieval of metal-rich hot Jupiters via transmission spectroscopy will thus mostly stem from the incompleteness and inaccuracy of line lists.

Keywords: Exoplanet atmospheric composition , Exoplanet atmospheres, Transmission spectroscopy
Atomic Hydrogen Scaling Relations at z ≈ 0.35. The atomic hydrogen (H I) properties of star-forming galaxies in the local universe are known to correlate with other galaxy properties via the "H I scaling relations." The redshift evolution of these relations serves as an important constraint on models of galaxy evolution. However, until recently, there were no estimates of the H I scaling relations at cosmological distances. Using data from a deep Giant Metrewave Radio Telescope H I 21 cm survey of the Extended Groth Strip, and the technique of spectral-line stacking, we determine the scaling relation between the H I mass and the stellar mass for star-forming galaxies at z ≈ 0.35. We use this measurement, along with the main-sequence relation in galaxies, to infer the dependence of the H I depletion timescale of these galaxies on their stellar mass. We find that massive star-forming galaxies at z ≈ 0.35, with stellar mass M * ≳ 109.5 M ⊙, are H I-poor compared to local star-forming galaxies of a similar stellar mass. However, their characteristic H I depletion time is lower by a factor of ≈5 than that of their local analogs, indicating a higher star formation efficiency at intermediate redshifts (similar to that at z ≈ 1). While our results are based on a relatively small cosmic volume and could thus be affected by cosmic variance, the short characteristic H I depletion timescales (≲3 Gyr) of massive star-forming galaxies at z ≈ 0.35 indicate that they must have acquired a significant amount of neutral gas through accretion from the circumgalactic medium over the past 4 Gyr, to avoid quenching of their star formation activity.

Keywords: Radio spectroscopy, High-redshift galaxies, Galaxy evolution, H I line emission
Astrometric Accelerations as Dynamical Beacons: A Giant Planet Imaged inside the Debris Disk of the Young Star AF Lep. We present the direct-imaging discovery of a giant planet orbiting the young star AF Lep, a 1.2 M ⊙ member of the 24 ± 3 Myr β Pic moving group. AF Lep was observed as part of our ongoing high-contrast imaging program targeting stars with astrometric accelerations between Hipparcos and Gaia that indicate the presence of substellar companions. Keck/NIRC2 observations in $L^{\prime} $ with the vector vortex coronagraph reveal a point source, AF Lep b, at ≈340 mas, which exhibits orbital motion at the 6σ level over the course of 13 months. A joint orbit fit yields precise constraints on the planet's dynamical mass of ${3.2}_{-0.6}^{+0.7}$ M Jup, semimajor axis of ${8.4}_{-1.3}^{+1.1}$ au, and eccentricity of ${0.24}_{-0.15}^{+0.27}$ . AF Lep hosts a debris disk located at ~50 au, but it is unlikely to be sculpted by AF Lep b, implying there may be additional planets in the system at wider separations. The stellar inclination (i * = ${54}_{-9}^{{+11}^\circ} $ ) and orbital inclination (i  o  = ${50}_{-12}^{{+9}^\circ} $ ) are in good agreement, which is consistent with the system having spin-orbit alignment. AF Lep b is the lowest-mass imaged planet with a dynamical mass measurement and highlights the promise of using astrometric accelerations as a tool to find and characterize long-period planets.

Keywords: Astrometric exoplanet detection, Direct imaging, Orbit determination, Debris disks, Extrasolar gaseous giant planets
GRB 191019A: A Short Gamma-Ray Burst in Disguise from the Disk of an Active Galactic Nucleus. Long and short gamma-ray bursts (GRBs), canonically separated at around 2 s duration, are associated with different progenitors: the collapse of a massive star and the merger of two compact objects, respectively. GRB 191019A was a long GRB (T 90 ~ 64 s). Despite the relatively small redshift z = 0.248 and Hubble Space Telescope follow-up observations, an accompanying supernova was not detected. In addition, the host galaxy did not have significant star formation activity. Here we propose that GRB 191019A was produced by a binary compact merger, whose prompt emission was stretched in time by the interaction with a dense external medium. This would be expected if the burst progenitor was located in the disk of an active galactic nucleus, as supported by the burst localization close to the center of its host galaxy. We show that the light curve of GRB 191019A can be well modeled by a burst of intrinsic duration t eng = 1.1 s and of energy E iso = 1051 erg seen moderately off axis, exploding in a medium of density ~107-108 cm-3. The double-peaked light curve carries the telltale features predicted for GRBs in high-density media, where the first peak is produced by the photosphere and the second by the overlap of reverse shocks that take place before the internal shocks could happen. This would make GRB 191019A the first confirmed stellar explosion from within an accretion disk, with important implications for the formation and evolution of stars in accretion flows and for gravitational-waves source populations.

Keywords: Gamma-ray bursts, Galaxy accretion disks, Stellar evolution
Evidence of a Quasiperiodic Global-scale Oscillation in the Near-surface Shear Layer of the Sun. We present evidence of hitherto undiscovered global-scale oscillations in the near-surface shear layer of the Sun. These oscillations are seen as large-scale variations of radial shear in both the zonal and meridional flows relative to their mean values. The variations cover all or most of a visible hemisphere, and reverse with a timescale on the order of a solar rotation. A large annual variation in the meridional shear anomaly is understandable in terms of the tilt of the rotation axis, but the rapid oscillations of the shear anomalies in both zonal and the meridional directions appear to be modulated in a more complex, not-quite-annual way, although the latter are also strongly modulated by the projected rotational axis angle. Small-scale anomalies in the neighborhood of active regions lend support to their solar origin and physical interpretation. These results were obtained by analyzing ring-diagram fits of low-order modes in high-resolution Doppler data from the Helioseismic and Magnetic Imager on the Solar Dynamics Observatory.

Keywords: Solar rotation, Solar differential rotation, Solar interior, Helioseismology, Solar convective zone, Solar meridional circulation, Solar activity
The Kinematic Bimodality: Efficient Feedback and Cold Gas Deficiency in Slow-rotating Galaxies. The bimodality in the stellar spin of low-redshift (massive) galaxies, ubiquitously existing at all star formation levels and in diverse environments, suggests that galaxies grow and quench through two diverged evolutionary pathways. For spheroid-dominated galaxies of slow stellar rotation, the age composition and metallicity of their stellar populations are evidence of a fast quenching history with significant gas outflows. In this work, we measure the spin parameter ${\lambda }_{{R}_{{\rm{e}}}}$ , i.e., the normalized specific angular momentum of stars, out of the MaNGA integral field spectroscopy for about 10,000 galaxies. Among the two-thirds with H I follow-up observations (z ≲ 0.05), we find that, compared to fast-rotating galaxies of the same stellar mass and star formation, the galaxy populations with slower rotation are generally more H I gas-poor, robust against further environmental restriction and with nondetections properly taken into account using the stacking technique. This cold gas deficit of slow-rotating galaxies is most apparent at high mass $\sim {10}^{11}{{ \mathcal M }}_{\odot }$ below the star formation main sequence, supporting the pivotal role of gas outflows in their quenching history. With hints from H I velocity distributions, we suspect that massive gas outflows among the slow-rotating population are facilitated by high ejective feedback efficiency, which is a result of extensive coupling between disturbed volume-filling cold gas and (commonly) biconical feedback from central black holes. By contrast, in fast-rotating disk galaxies the feedback energy mostly goes to the hot circumgalactic medium rather than directly impacting the dense and planar cold gas, thus making the feedback mainly preventive against further gas inflow.

Keywords: Galaxies, Galactic and extragalactic astronomy
Optical Forbidden Emission Line Spectro-astrometry of T CrA: Evidence for a Multiple System and Multiple Jets. Spectro-astrometry is applied to echelle spectra of the young intermediate-mass star T CrA. The aim is to better understand the origin of the [O I] and [S II] emission from T CrA and further explore the usefulness of spectro-astrometry in the search for a reliable tracer of MHD disk winds. The analysis reveals a small-scale curved jet in an east-west direction and inclined parallel to the plane of the sky. It is the inclination of this jet that led to the classification of the forbidden emission lines as a low-velocity component. Thus, spectro-astrometry highlights here that for close to edge-on disks spatial information is necessary. The position angle of the jet is not perpendicular to the position angle of the accretion disk nor does it agree with older observations of outflows likely driven by T CrA. The mass outflow rate of 5-10 × 10-8 M ☉ yr-1 is within the range for intermediate-mass stars. We conclude that more than one outflow is driven by the T CrA system and that the curvature seen in the first detection of an outflow from T CrA and in the data presented here is likely due to the multiplicity of the system. * Based on data collected by UVES 089.C-0299(A) observations at the VLT on Cerro Paranal (Chile), which is operated by the European Southern Observatory (ESO).

Keywords: Stellar accretion disks, Stellar jets, Interstellar medium wind, Star formation
On the Onset Delays of Solar Energetic Electrons and Protons: Evidence for a Common Accelerator. The processes responsible for the acceleration of solar energetic particles (SEPs) are still not well understood, including whether SEP electrons and protons are accelerated by common or separate processes. Using a numerical particle transport model that includes both pitch-angle and perpendicular spatial diffusion, we simulate, among other quantities, the onset delay for MeV electrons and protons and compare the results to observations of SEPs from widely separated spacecraft. Such observations have previously been interpreted, in a simple scenario assuming no perpendicular diffusion, as evidence for different electron and proton sources. We show that, by assuming a common particle source together with perpendicular diffusion, we are able to simultaneously reproduce the onset delays for both electrons and protons. We argue that this points toward a common accelerator for these particles. Moreover, a relatively broad particle source is required in the model to correctly describe the observations. This is suggestive of diffusive shock acceleration occurring at large shock structures playing a significant role in the acceleration of these SEPs.

Keywords: Solar energetic particles
Neutron Star Phase Transition as the Origin for the Fast Radio Bursts and Soft Gamma-Ray Repeaters of SGR J1935 + 2154. Magnetars are believed to be neutron stars (NSs) with strong magnetic fields. X-ray flares and fast radio bursts (FRBs) have been observed from the magnetar (soft gamma-ray repeater, SGR J1935+2154). We propose that the phase transition of the NS can power the FRBs and SGRs. Based on the equation of state provided by the MIT bag model and the mean field approximation, we solve the Tolman-Oppenheimer-Volkoff equations to get the NS structure. With the spin-down of the NS, the hadronic shell gradually transfers to the quark shell. The gravitational potential energy released by one time of the phase transition can be achieved. The released energy, time interval between two successive phase transitions, and glitch are all consistent with the observations of the FRBs and the X-ray flares from SGR J1935 + 2154. We conclude that the phase transition of an NS is a plausible mechanism to power the SGRs as well as the repeating FRBs.

Keywords: Neutron stars, Soft gamma-ray repeaters, Magnetars, Radio transient sources
Identification of Extended Emission Gamma-Ray Burst Candidates Using Machine Learning. Gamma-ray bursts (GRBs) have been classified traditionally based on their duration. The increasing number of extended emission (EE) GRBs, lasting typically more than 2s but with properties similar to those of short GRBs, challenges the traditional classification criteria. In this work, we use the t-distributed stochastic neighbor embedding (t-SNE), a machine-learning technique, to classify GRBs. We present the results for GRBs observed until 2022 July by the Swift/BAT (Burst Alert Telescope) instrument in all its energy bands. We show the effects of varying the learning rate and perplexity parameters as well as the benefit of preprocessing the data by a nonparametric noise-reduction technique. Consistently with previous works, we show that the t-SNE method separates GRBs into two subgroups. We also show that EE GRBs reported by various authors under different criteria tend to cluster in a few regions of our t-SNE maps and identify seven new EE GRB candidates by using the gamma-ray data provided by the automatic pipeline of Swift/BAT and the proximity with previously identified EE GRBs.

Keywords: Gamma-ray bursts, High energy astrophysics
Physics Beyond the Standard Model with Future X-Ray Observatories: Projected Constraints on Very-light Axion-like Particles with Athena and AXIS. Axion-like particles (ALPs) are well-motivated extensions of the Standard Model of Particle Physics and a generic prediction of some string theories. X-ray observations of bright active galactic nuclei (AGNs) hosted by rich clusters of galaxies are excellent probes of very-light ALPs, with masses $\mathrm{log}({m}_{{\rm{a}}}/\mathrm{eV})\lt -12.0$ . We evaluate the potential of future X-ray observatories, particularly Athena and the proposed AXIS, to constrain ALPs via observations of cluster-hosted AGNs, taking NGC 1275 in the Perseus cluster as our exemplar. Assuming perfect knowledge of the instrument calibration, we show that a modest exposure (200 ks) of NGC 1275 by Athena permits us to exclude all photon-ALP couplings g aγ  &gt; 6.3 × 10-14 GeV-1 at the 95% confidence level, as previously shown by Conlon et al., representing a factor of 10 improvement over current limits. We then proceed to assess the impact of realistic calibration uncertainties on the Athena projection by applying a standard Cash likelihood procedure, showing the projected constraints on g aγ  weaken by a factor of 10 (back to the current most sensitive constraints). However, we show how the use of a deep neural network can disentangle the energy-dependent features induced by instrumental miscalibration and those induced by photon-ALP mixing, allowing us to recover most of the sensitivity to the ALP physics. In our explicit demonstration, the machine learning applied allows us to exclude g aγ  &gt; 2.0 × 10-13 GeV-1, complementing the projected constraints of next-generation ALP dark matter birefringent cavity searches for very-light ALPs. Finally, we show that a 200 ks AXIS/on-axis observation of NGC 1275 will tighten the current best constraints on very-light ALPs by a factor of 3.

Keywords: Galaxy clusters, X-ray telescopes, X-ray active galactic nuclei, Magnetic fields, Dark matter, Particle astrophysics
Pixelated Reconstruction of Foreground Density and Background Surface Brightness in Gravitational Lensing Systems Using Recurrent Inference Machines. Modeling strong gravitational lenses in order to quantify distortions in the images of background sources and to reconstruct the mass density in foreground lenses has been a difficult computational challenge. As the quality of gravitational lens images increases, the task of fully exploiting the information they contain becomes computationally and algorithmically more difficult. In this work, we use a neural network based on the recurrent inference machine to reconstruct simultaneously an undistorted image of the background source and the lens mass density distribution as pixelated maps. The method iteratively reconstructs the model parameters (the image of the source and a pixelated density map) by learning the process of optimizing the likelihood given the data using the physical model (a ray-tracing simulation), regularized by a prior implicitly learned by the neural network through its training data. When compared to more traditional parametric models, the proposed method is significantly more expressive and can reconstruct complex mass distributions, which we demonstrate by using realistic lensing galaxies taken from the IllustrisTNG cosmological hydrodynamic simulation.

Keywords: Nonparametric inference, Convolutional neural networks, Astronomical simulations
Early Planet Formation in Embedded Disks (eDisk). I. Overview of the Program and First Results. We present an overview of the Large Program, "Early Planet Formation in Embedded Disks (eDisk)," conducted with the Atacama Large Millimeter/submillimeter Array (ALMA). The ubiquitous detections of substructures, particularly rings and gaps, in protoplanetary disks around T Tauri stars raise the possibility that at least some planet formation may have already started during the embedded stages of star formation. In order to address exactly how and when planet formation is initiated, the program focuses on searching for substructures in disks around 12 Class 0 and 7 Class I protostars in nearby (&lt;200 pc) star-forming regions through 1.3 mm continuum observations at a resolution of ~7 au (0.″04). The initial results show that the continuum emission, mostly arising from dust disks around the sample protostars, has relatively few distinctive substructures, such as rings and spirals, in marked contrast to Class II disks. The dramatic difference may suggest that substructures quickly develop in disks when the systems evolve from protostars to Class II sources, or alternatively that high optical depth of the continuum emission could obscure internal structures. Kinematic information obtained through CO isotopologue lines and other lines reveals the presence of Keplerian disks around protostars, providing us with crucial physical parameters, in particular, the dynamical mass of the central protostars. We describe the background of the eDisk program, the sample selection and their ALMA observations, and the data reduction, and we also highlight representative first-look results.

Keywords: Planetary system formation, Protostars, Submillimeter astronomy, Protoplanetary disks
Early Planet Formation in Embedded Disks (eDisk). II. Limited Dust Settling and Prominent Snow Surfaces in the Edge-on Class I Disk IRAS 04302+2247. While dust disks around optically visible, Class II protostars are found to be vertically thin, when and how dust settles to the midplane are unclear. As part of the Atacama Large Millimeter/submillimeter Array large program, Early Planet Formation in Embedded Disks, we analyze the edge-on, embedded, Class I protostar IRAS 04302+2247, also nicknamed the "Butterfly Star." With a resolution of 0.″05 (8 au), the 1.3 mm continuum shows an asymmetry along the minor axis that is evidence of an optically thick and geometrically thick disk viewed nearly edge-on. There is no evidence of rings and gaps, which could be due to the lack of radial substructure or the highly inclined and optically thick view. With 0.″1 (16 au) resolution, we resolve the 2D snow surfaces, i.e., the boundary region between freeze-out and sublimation, for 12CO J = 2-1, 13CO J = 2-1, C18O J = 2-1, H 2CO J = 30,3-20,2, and SO J = 65-54, and constrain the CO midplane snow line to ~130 au. We find Keplerian rotation around a protostar of 1.6 ± 0.4 M ☉ using C18O. Through forward ray-tracing using RADMC-3D, we find that the dust scale height is ~6 au at a radius of 100 au from the central star and is comparable to the gas pressure scale height. The results suggest that the dust of this Class I source has yet to vertically settle significantly.

Keywords: Protostars, Protoplanetary disks, Interstellar medium, Circumstellar disks, Submillimeter astronomy
Early Planet Formation in Embedded Disks (eDisk). III. A First High-resolution View of Submillimeter Continuum and Molecular Line Emission toward the Class 0 Protostar L1527 IRS. Studying the physical and chemical conditions of young embedded disks is crucial to constrain the initial conditions for planet formation. Here we present Atacama Large Millimeter/submillimeter Array observations of dust continuum at ~0.″06 (8 au) resolution and molecular line emission at ~0.″17 (24 au) resolution toward the Class 0 protostar L1527 IRS from the Large Program eDisk (Early Planet Formation in Embedded Disks). The continuum emission is smooth without substructures but asymmetric along both the major and minor axes of the disk as previously observed. The detected lines of 12CO, 13CO, C18O, H2CO, c-C3H2, SO, SiO, and DCN trace different components of the protostellar system, with a disk wind potentially visible in 12CO. The 13CO brightness temperature and the H2CO line ratio confirm that the disk is too warm for CO freezeout, with the snowline located at ~350 au in the envelope. Both molecules show potential evidence of a temperature increase around the disk-envelope interface. SO seems to originate predominantly in UV-irradiated regions such as the disk surface and the outflow cavity walls rather than at the disk-envelope interface as previously suggested. Finally, the continuum asymmetry along the minor axis is consistent with the inclination derived from the large-scale (100″ or 14,000 au) outflow, but opposite to that based on the molecular jet and envelope emission, suggesting a misalignment in the system. Overall, these results highlight the importance of observing multiple molecular species in multiple transitions to characterize the physical and chemical environment of young disks.

Keywords: Interstellar molecules, Protostars