adsabs/SciX_UAT_keywords huggingface dataset:
A Data Science Platform to Enable Time-domain Astronomy

SkyPortal is an open-source software package designed to discover interesting transients efficiently, manage follow-up, perform characterization, and visualize the results. By enabling fast access to archival and catalog data, crossmatching heterogeneous data streams, and the triggering and monitoring of on-demand observations for further characterization, a SkyPortal-based platform has been operating at scale for >2 yr for the Zwicky Transient Facility Phase II community, with hundreds of users, containing tens of millions of time-domain sources, interacting with dozens of telescopes, and enabling community reporting. While SkyPortal emphasizes rich user experiences across common front-end workflows, recognizing that scientific inquiry is increasingly performed programmatically, SkyPortal also surfaces an extensive and well-documented application programming interface system. From back-end and front-end software to data science analysis tools and visualization frameworks, the SkyPortal design emphasizes the reuse and leveraging of best-in-class approaches, with a strong extensibility ethos. For instance, SkyPortal now leverages ChatGPT large language models to generate and surface source-level human-readable summaries automatically. With the imminent restart of the next generation of gravitational-wave detectors, SkyPortal now also includes dedicated multimessenger features addressing the requirements of rapid multimessenger follow-up: multitelescope management, team/group organizing interfaces, and crossmatching of multimessenger data streams with time-domain optical surveys, with interfaces sufficiently intuitive for newcomers to the field. This paper focuses on the detailed implementations, capabilities, and early science results that establish SkyPortal as a community software package ready to take on the data science challenges and opportunities presented by this next chapter in the multimessenger era.

Keywords: open source software; astronomy software; time domain astronomy
A Dust Detection Database for the Inner Heliosphere Using the Parker Solar Probe Spacecraft

A database of in situ dust impact detections made by the Parker Solar Probe spacecraft is created to facilitate studies of interplanetary dust dynamics in the inner heliosphere. A standardized dust detection methodology is established and tested for validity. Individual impact detections are included in the database, and are used to derive dust impact rates. Impact rates are corrected for effects related to high-amplitude plasma waves and undercounting due to finite detection window duration. These corrections suggest that: (i) most dust impacts on Parker Solar Probe are consistent with a random process; and (ii) the true dust impact rate may be ~50% greater than the impact rate determined using uncorrected data for certain portions of the orbit, especially near perihelion.

Keywords: interplanetary dust; solar wind; space vehicles; zodiacal cloud; astronomy databases
Gravitational Lensing Formalism in a Curved Arc Basis: A Continuous Description of Observables and Degeneracies from the Weak to the Strong Lensing Regime

Gravitationally lensed curved arcs provide a wealth of information about the underlying lensing distortions. Extracting precise lensing information from extended sources is a key component in many studies aiming to answer fundamental questions about the universe. To maintain accuracy with increased precision, it is of vital importance to characterize and understand the impact of degeneracies inherent in lensing observables. In this work, we present a formalism to describe the gravitational lensing distortion effects resulting in curved extended arcs based on the eigenvectors and eigenvalues of the local lensing Jacobian and their directional differentials. We identify a nonlocal and nonlinear extended deflector basis that inherits these local properties. Our parameterization is tightly linked to observable features in extended sources and allows one to accurately extract the lensing information of extended images without imposing an explicit global deflector model. We quantify what degeneracies can be broken based on specific assumptions about the local lensing nature and assumed intrinsic source shape. Our formalism is applicable from the weak linear regime to the semi-linear regime and all the way up to the highly nonlinear regime of highly magnified arcs of multiple images. The methodology and implementation presented in this work provides a framework to assessing systematics, to guide inference efforts in the right choices in complexity based on the data at hand, and to quantify the lensing information extracted in a model-independent way (https://github.com/sibirrer/curved_arcs).

Keywords: gravitational lensing; strong gravitational lensing; weak gravitational lensing
Early-time Ultraviolet Spectroscopy and Optical Follow-up Observations of the Type IIP Supernova 2021yja

We present three epochs of early-time ultraviolet (UV) and optical HST/STIS spectroscopy of the young, nearby Type IIP supernova (SN) 2021yja. We complement the HST data with two earlier epochs of Swift UVOT spectroscopy. The HST and Swift UVOT spectra are consistent with those of other well-studied Type IIP SNe. The UV spectra exhibit rapid cooling at early times, while less dramatic changes are seen in the optical. We also present Lick/KAIT optical photometry up to the late-time tail phase, showing a very long plateau and shallow decline compared with other SNe IIP. Our modeling of the UV spectrum with the TARDIS radiative transfer code produces a good fit for a high-velocity explosion, a low total extinction E(B - V) = 0.07 mag, and a subsolar metallicity. We do not find a significant contribution to the UV flux from an additional heating source, such as interaction with the circumstellar medium, consistent with the observed flat plateau. Furthermore, the velocity width of the Mg II λ2798 line is comparable to that of the hydrogen Balmer lines, suggesting that the UV emission is confined to a region close to the photosphere.

Keywords: type ii supernovae; core-collapse supernovae; ultraviolet astronomy
PSR J1641+3627F: A Low-mass He White Dwarf Orbiting a Possible High-mass Neutron Star in the Globular Cluster M13

We report on the discovery of the companion star to the millisecond pulsar J1631+3627F in the globular cluster M13. By means of a combination of optical and near-UV high-resolution observations obtained with the Hubble Space Telescope, we identified the counterpart at the radio source position. Its location in the color-magnitude diagrams reveals that the companion star is a faint ( $V\approx 24.3$ ) He-core white dwarf. We compared the observed companion magnitudes with those predicted by state-of-the-art binary evolution models and found out that it has a mass of $0.23\pm 0.03\,{M}_{\odot }$ , a radius of ${0.033}_{-0.005}^{+0.004}\,{R}_{\odot }$ , and a surface temperature of $11,{500}_{-1300}^{+1900}$ K. Combining the companion mass with the pulsar mass function is not enough to determine the orbital inclination and the neutron star mass; however, the last two quantities become correlated: we found that either the system is observed at a low-inclination angle, or the neutron star is massive. In fact, assuming that binaries are randomly aligned with respect to the observer line of sight, there is a $\sim 70 \% $ of probability that this system hosts a neutron star more massive than $1.6\,{M}_{\odot }$ . In fact, the maximum and median mass of the neutron star, corresponding to orbital inclination angles of 90° and 60°, are ${M}_{\mathrm{NS},\max }=3.1\pm 0.6\,{M}_{\odot }$ and ${M}_{\mathrm{NS},\mathrm{med}}=2.4\pm 0.5\,{M}_{\odot }$ , respectively. On the other hand, also assuming an empirical neutron star mass probability distribution, we found that this system could host a neutron star with a mass of $1.5\pm 0.1\,{M}_{\odot }$ if orbiting with a low-inclination angle around 40°.

Keywords: binary pulsars; pulsars; compact binary stars; globular star clusters; star clusters; white dwarf stars; binary stars; neutron stars; hst photometry; millisecond pulsars
Inferring Stellar Parameters from Iodine-imprinted Keck/HIRES Spectra with Machine Learning

The properties of exoplanet host stars are traditionally characterized through a detailed forward-modeling analysis of high-resolution spectra. However, many exoplanet radial velocity surveys employ iodine-cell-calibrated spectrographs, such that the vast majority of spectra obtained include an imprinted forest of iodine absorption lines. For surveys that use iodine cells, iodine-free "template" spectra must be separately obtained for precise stellar characterization. These template spectra often require extensive additional observing time to obtain, and they are not always feasible to obtain for faint stars. In this paper, we demonstrate that machine-learning methods can be applied to infer stellar parameters and chemical abundances from iodine-imprinted spectra with high accuracy and precision. The methods presented in this work are broadly applicable to any iodine-cell-calibrated spectrograph. We make publicly available our spectroscopic pipeline, the Cannon HIRES Iodine Pipeline, which derives stellar parameters and 15 chemical abundances from iodine-imprinted spectra of FGK stars and which has been set up for ease of use with Keck/HIRES spectra. Our proof of concept offers an efficient new avenue to rapidly estimate a large number of stellar parameters even in the absence of an iodine-free template spectrum.

Keywords: stellar classification; stellar spectral lines; stellar spectral types; exoplanets; exoplanet catalogs; high resolution spectroscopy; computational methods; stellar abundances; chemical abundances
Nucleosynthesis in Outflows from Black Hole-Neutron Star Merger Disks with Full GR(ν)RMHD

Along with binary neutron star mergers, the inspiral and merger of a black hole and a neutron star is a predicted site of r-process nucleosynthesis and associated kilonovae. For the right mass ratio, very large amounts of neutron-rich material (relative to the dynamical ejecta) may become unbound from the post-merger accretion disk. We simulate a suite of four post-merger disks with three-dimensional general-relativistic magnetohydrodynamics with time-dependent Monte Carlo neutrino transport. We find that within 104 GM BH/c 3 (~200-500 ms), the outflows from these disks are very close to the threshold conditions for robust r-process nucleosynthesis. For these conditions, the detailed properties of the outflow determine whether a full r-process can or cannot occur, implying that a wide range of observable phenomena is possible. We show that on average the disk outflow lanthanide fraction is suppressed relative to the solar isotopic pattern. In combination with the dynamical ejecta, these outflows imply a kilonova with both blue and red components.

Keywords: nucleosynthesis
Expected Investigation of the (65803) Didymos-Dimorphos System Using the RGB Spectrophotometry Data Set from the LICIACube Unit Key Explorer (LUKE) Wide-angle Camera

The Light Italian Cubesat for Imaging of Asteroids (LICIACube) is part of the NASA Double Asteroid Redirection Test (DART), the first mission aiming to demonstrate the applicability of the kinetic impactor method for planetary defense. The mission was launched on 2021 November 24 to perform the impact experiment on Dimorphos, the small secondary of the binary asteroid (65803) Didymos. The 6U LICIACube, stored as a piggyback of the DART spacecraft, is the first Italian mission operating in deep space managed by the Italian Space Agency that will witness the effects of the DART impact on Dimorphos. On board LICIACube, there is a suite of cameras that will perform imaging of Didymos and Dimorphos to investigate the DART impact effects and study the binary system. Among them, the LICIACube Unit Key Explorer (LUKE), a wide-angle camera coupled to an RGB Bayer pattern filter, will be pivotal to constrain the surface composition and heterogeneity of the binary system due to differences in surface properties linked with possible space weathering effects and/or the presence of exogenous material. Multiband photometric analysis of LUKE data and laboratory experiments in support of data interpretation will provide new insights on the binary asteroid nature and evolution. Moreover, photometric phase curve analysis will reveal the scattering properties of the granular surface medium providing important constraints for the microphysical properties of the Didymos-Dimorphos system. In this work, we will present the state of the art of the LUKE scientific activities with an overview of the instrument setup, science operations, and expected results.

Keywords: asteroids; near-earth objects; multivariate analysis; laboratory astrophysics; phase angle; rgb photometry; near infrared astronomy
Low-frequency Radio Continuum Imaging and SED Modeling of 11 LIRGs: Radio-only and FUV to Radio Bands

We present a detailed analysis of 11 local luminous infrared galaxies from ultraviolet through far-infrared to radio (~70 MHz to ~15 GHz) bands. We derive the astrophysical properties through spectral energy distribution (SED) modeling using the Code Investigating GALaxy Emission (CIGALE) and UltraNest codes. The radio SEDs include our new observations at 325 and 610 MHz from the GMRT and the measurements from public archives. Our main results are (1) radio SEDs show turnovers and bends, (2) the synchrotron spectral index of the fitted radio spectra ranges between -0.5 and -1.7, and (3) the infrared luminosity, dust mass, dust temperature, stellar mass, star formation rates (SFRs), and active galactic nuclei (AGN) fraction obtained from CIGALE fall within the range exhibited by galaxies of the same class. The ratio of 60 μm infrared and 1.4 GHz radio luminosity, the 1.4 GHz thermal fraction, and emission measure range between 2.1 and 2.9, 0.1% and 10%, 0.02 and 269.5 × 106 cm-6 pc, respectively. We conclude that the turnovers seen in the radio SEDs are due to free-free absorption; this is supported by the low AGN fraction derived from the CIGALE analysis. The decomposed 1.4 GHz thermal and nonthermal radio luminosities allowed us to compute the SFR using scaling relations. A positive correlation is observed between the SFRIR obtained 10 Myr ago (compared to 100 Myr ago) and 1.4 GHz radio (total and nonthermal) because similar synchrotron lifetimes are expected for typical magnetic field strengths observed in these galaxies (≈50 μG).

Keywords: radio continuum emission; luminous infrared galaxies; spectral energy distribution; interstellar medium; galaxy photometry
Grid-based Atmospheric Retrievals for Reflected-light Spectra of Exoplanets Using PSGnest

Techniques to retrieve the atmospheric properties of exoplanets via direct observation of their reflected light have often been limited in scope owing to computational constraints imposed by the forward-model calculations. We have developed a new set of techniques that significantly decrease the time required to perform a retrieval while maintaining accurate results. We constructed a grid of 1.4 million precomputed geometric albedo spectra valued at discrete sets of parameter points. Spectra from this grid are used to produce models for a fast and efficient nested sampling routine called PSGnest. Beyond the upfront time to construct a spectral grid, the amount of time to complete a full retrieval using PSGnest is on the order of seconds to minutes using a personal computer. An extensive evaluation of the error induced from interpolating intermediate spectra from the grid indicates that this bias is insignificant compared to other retrieval error sources, with an average coefficient of determination between interpolated and true spectra of 0.998. We apply these new retrieval techniques to help constrain the optimal bandpass centers for retrieving various atmospheric and bulk parameters from a LuvEx-type mission observing several planetary archetypes. We show that spectral observations made using a 20% bandpass centered at 0.73 μm can be used alongside our new techniques to make detections of H2O and O2 without the need to increase observing time beyond what is necessary for a signal-to-noise ratio of 10. The methods introduced here will enable robust studies of the capabilities of future observatories to characterize exoplanets.

Keywords: exoplanet astronomy; computational astronomy; computational methods
Identification of Coronal Holes on AIA/SDO Images Using Unsupervised Machine Learning

Through its magnetic activity, the Sun governs the conditions in Earth's vicinity, creating space weather events, which have drastic effects on our space- and ground-based technology. One of the most important solar magnetic features creating the space weather is the solar wind that originates from the coronal holes (CHs). The identification of the CHs on the Sun as one of the source regions of the solar wind is therefore crucial to achieve predictive capabilities. In this study, we used an unsupervised machine-learning method, k-means, to pixel-wise cluster the passband images of the Sun taken by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory in 171, 193, and 211 Å in different combinations. Our results show that the pixel-wise k-means clustering together with systematic pre- and postprocessing steps provides compatible results with those from complex methods, such as convolutional neural networks. More importantly, our study shows that there is a need for a CH database where a consensus about the CH boundaries is reached by observers independently. This database then can be used as the "ground truth," when using a supervised method or just to evaluate the goodness of the models.

Keywords: gravitational waves; detection; space weather
EMPRESS. II. Highly Fe-enriched Metal-poor Galaxies with ∼1.0 (Fe/O)⊙ and 0.02 (O/H)⊙: Possible Traces of Supermassive (>300 M⊙) Stars in Early Galaxies

We present element abundance ratios and ionizing radiation of local young low-mass (∼106 M⊙) extremely metal-poor galaxies (EMPGs) with a 2% solar oxygen abundance (O/H)⊙ and a high specific star formation rate (sSFR ∼ 300 Gyr-1) and other (extremely) metal-poor galaxies, which are compiled from Extremely Metal-Poor Representatives Explored by the Subaru Survey (EMPRESS) and the literature. Weak emission lines such as [Fe III] λ4658 and He II λ4686 are detected in very deep optical spectra of the EMPGs taken with 8 m class telescopes, including Keck and Subaru, enabling us to derive element abundance ratios with photoionization models. We find that neon-to-oxygen and argon-to-oxygen ratios are comparable to those of known local dwarf galaxies and that the nitrogen-to-oxygen abundance ratios (N/O) are lower than 20% (N/O)⊙, consistent with the low oxygen abundance. However, the iron-to-oxygen abundance ratios (Fe/O) of the EMPGs are generally high; the EMPGs with the 2%-solar oxygen abundance show high Fe/O ratios of ∼90%-140% (Fe/O)⊙, which are unlikely to be explained by suggested scenarios of Type Ia supernova iron productions, iron's dust depletion, and metal-poor gas inflow onto previously metal-riched galaxies with solar abundances. Moreover, the EMPGs with the 2%-solar oxygen abundance have very high He II λ4686/Hβ ratios of ∼1/40, which are not reproduced by existing models of high-mass X-ray binaries with progenitor stellar masses <120 M⊙. Comparing stellar-nucleosynthesis and photoionization models with a comprehensive sample of EMPGs identified by this and previous EMPG studies, we propose that both the high Fe/O ratios and the high He II λ4686/Hβ ratios are explained by the past existence of supermassive (>300 M⊙) stars, which may evolve into intermediate-mass black holes (≳100 M⊙). * Partly based on data obtained with the Subaru Telescope. The Subaru Telescope is operated by the National Astronomical Observatory of Japan. † The data presented herein were partly obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. ‡ This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: interstellar medium; metallicity; galaxy chemical evolution; emission line galaxies; galaxy evolution; massive stars; black holes
Custom JWST NIRSpec/IFU and MIRI/MRS Data Reduction Pipelines for Solar System Targets

We present custom JWST data reduction pipelines for JWST NIRSpec/IFU and MIRI/MRS observations of solar system objects. The pipelines simplify the process of reducing the JWST observations, and include custom steps to significantly improve the data quality. Our custom processing routines include a "desaturation" routine to reduce the effect of saturation while still maintaining high signal-to-noise ratio, and custom flat field correction code to remove the significant artifacts found in MIRI/MRS observations. The pipelines also automatically generate a series of quick look plots and animations to simplify exploration of a dataset. These custom JWST pipelines can be downloaded from https://github.com/JWSTGiantPlanets/pipelines.

Keywords: astronomy data reduction; astronomy image processing; astronomy data visualization; astronomy software
New Approach for Analyzing Dynamical Processes on the Surface of Photospheric Vortex Tubes

The majority of studies on multi-scale vortex motions employ a two-dimensional geometry by using a variety of observational and numerical data. This approach limits the understanding the nature of physical processes responsible for vortex dynamics. Here, we develop a new methodology to extract essential information from the boundary surface of vortex tubes. 3D high-resolution magneto-convection MURaM numerical data has been used to analyze photospheric intergranular velocity vortices. The Lagrangian averaged vorticity deviation technique was applied to define the centers of vortex structures and their boundary surfaces based on the advection of fluid elements. These surfaces were mapped onto a constructed envelope grid that allows the study of the key plasma parameters as functions of space and time. Quantities that help in understanding the dynamics of the plasma, e.g., Lorentz force, pressure force, and plasma-β were also determined. Our results suggest that, while density and pressure have a rather global behavior, the other physical quantities undergo local changes, with their magnitude and orientation changing in space and time. At the surface, the mixing in the horizontal direction is not efficient, leading to appearance of localized regions with higher/colder temperatures. In addition, the analysis of the MHD Poynting flux confirms that the majority of the energy is directed in the horizontal direction. Our findings also indicate that the pressure and magnetic forces that drive the dynamics of the plasma on vortex surfaces are unbalanced and therefore the vortices do not rotate as a rigid body.

Keywords: solar granulation; magnetohydrodynamical simulations; solar photosphere; solar atmospheric motions