Sazuna/UAT_keywords huggingface dataset:
3D Nonequilibrium Ionization and Spectroscopic Modeling of Coronal Mass Ejections. I. Comparison with Hinode/EIS Observations. High-resolution EUV spectroscopy provides an informative diagnostic tool for the early evolution of coronal mass ejections (CMEs) since it can directly measure many physical properties of CME plasma close to the Sun that cannot be determined from white-light coronagraphs or narrowband imagers. The Hinode/EUV Imaging Spectrometer (EIS) captured a series of high-resolution EUV spectra of the 2008 April 9 event, also known as the "Cartwheel CME," during its initial acceleration period. CMEs are inherently dynamic events, driving the plasma from ionization equilibrium, which makes the nonequilibrium ionization (NEI) effects important when analyzing spectral observations. In this work, we performed simulations of the Cartwheel CME using the Alfvén Wave Solar atmosphere Model (AWSoM) to provide insight into the plasma structure and dynamics during the early evolution of this CME. For the first time, we combined self-consistent nonequilibrium charge state calculations in the EUV spectral line synthesis for a CME simulation to account for the plasma departures from ionization equilibrium everywhere in the CME. In this first paper of the series, we compare the simulation results to the EIS observations of this event to assess the quality of the AWSoM predictions. We find that the CME is out of equilibrium, indicating that NEI effects should be considered in the EUV spectral synthesis. Overall, the model reproduces the thermodynamic evolution of the CME in the low solar corona well, as compared to the EIS observations.

Keywords: Solar coronal mass ejections, Solar extreme ultraviolet emission
First Results from the JWST Early Release Science Program Q3D: The Fast Outflow in a Red Quasar at z = 0.44. Quasar feedback may play a key role in the evolution of massive galaxies. The dust-reddened quasar F2M110648.35+480712 at z = 0.4352 is one of the few cases at its redshift that exhibits powerful quasar feedback through bipolar outflows. Our new observation with the integral field unit mode of the Near-infrared Spectrograph on board JWST opens a new window to examine this spectacular outflow through the Paα emission line with ~3× better spatial resolution than previous work. The morphology and kinematics of the Paα nebula confirm the existence of a bipolar outflow extending on a scale of ∼17 × 14 kpc and with a velocity reaching ∼1100 km s−1. The higher spatial resolution of our new observation leads to more reliable measurements of outflow kinematics. Considering only the spatially resolved outflow and assuming an electron density of 100 cm−2, the mass, momentum, and kinetic energy outflow rates are ∼50─210 M⊙ yr−1, ∼(0.3─1.7) × 1036 dynes (∼14%─78% of the quasar photon momentum flux), and ∼(0.16─1.27) × 1044 erg s−1 (∼0.02%─0.20% of the quasar bolometric luminosity), respectively. The local instantaneous outflow rates generally decrease radially. We infer that the quasar is powerful enough to drive the outflow, while stellar processes cannot be overlooked as a contributing energy source. The mass outflow rate is ∼0.4─1.5 times the star formation rate, and the ratio of kinetic energy outflow rate to the quasar bolometric luminosity is comparable to the minimum value required for negative quasar feedback in simulations. This outflow may help regulate the star formation activity within the system to some extent.

Keywords: Active galactic nuclei, Quasars
The Quest for a Stable Disk. The majority of disk galaxies manifest spirals and/or bars that are believed to result from dynamical instabilities. However, some galaxies have featureless disks, which are therefore inferred to be dynamically stable. Yet despite many years of effort, theorists have been unable to construct realistic models of galaxy disks that possess no instabilities and therefore could remain featureless. This conclusion has been reached through simulations for the most part, some of which have been confirmed by linear stability analyses. A. Toomre (1981) claimed that the Mestel disk, embedded in an equal-mass halo, is a notable counterexample, but his prediction of stability could not be reproduced in simulations, due to complicated nonlinear effects that caused secular growth of Poisson noise–driven disturbances until strong features emerged. Here, we revisit this issue and show that simply eliminating the most nearly circular orbits from Toomre's disk model can inhibit troublesome secular growth. We also present both 2D and 3D simulations of particle disks that remain featureless for over 50 orbit periods. We report that spiral evolution naturally depletes circular orbits and that the radial velocity distribution in the featureless disks of S0 galaxies should have negative kurtosis.

Keywords: Galaxy structure, Galaxy dynamics, Galaxy evolution, Spiral galaxies
The Sunburst Arc with JWST. III. An Abundance of Direct Chemical Abundances. We measure the gas-phase abundances of the elements He, N, O, Ne, S, Ar, and Fe in an individual H II region known to be leaking Lyman-continuum photons in the Sunburst Arc, a highly magnified galaxy at redshift z = 2.37. We detect the temperature-sensitive auroral lines [S II] λλ4070, 4076, [O III] λ4363, [S III] λ6314, [O II] λλ7320, 7330, and [Ne III] λ3343 in a stacked spectrum of five multiple images of the Lyman-continuum emitter (LCE), from which we directly measure the electron temperature in the low-, intermediate-, and high-ionization zones. We also detect the density-sensitive doublets of [O II] λλ3727, 3730, [S II] λλ6718, 6733, and [Ar IV] λλ4713, 4741, which constrain the density in both the low- and high-ionization gas. With these temperature and density measurements, we measure gas-phase abundances with similar rigor as studies of local galaxies and H II regions. We measure a gas-phase metallicity for the LCE of  , and find an enhanced nitrogen abundance  . This nitrogen abundance is consistent with enrichment from a population of Wolf–Rayet stars, additional signatures of which are reported in a companion paper. Abundances of sulfur, argon, neon, and iron are consistent with local low-metallicity H II regions and low-redshift galaxies. This study represents the most complete chemical abundance analysis of an individual H II region at Cosmic Noon to date, which enables direct comparisons between local H II regions and those in the distant Universe.

Keywords: Strong gravitational lensing, Chemical abundances, Abundance ratios
Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic Code. Photoevaporation in exoplanet atmospheres is thought to contribute to the shaping of the small planet radius valley. Escaping atmospheres have been detected in transmission across a variety of exoplanet types, from hot Jupiters to mini-Neptunes. However, no work has yet considered whether outflows might also be detectable in emission. We introduce pyTPCI, a new, open-source self-consistent 1D radiative-hydrodynamics code that is an improved version of The PLUTO-CLOUDY Interface. We use pyTPCI to model seven exoplanets (HD 189733b, HD 209458b, WASP-69b, WASP-107b, TOI-1430b, TOI-560b, and HAT-P-32b) at varying metallicities and compute their emission spectra to investigate their detectability across a variety of spectral lines. We calculate the eclipse depths and signal-to-noise ratios (SNRs) of these lines for a 10 m class telescope with a high-resolution spectrograph, taking into account appropriate line broadening mechanisms. We show that the most detectable spectral lines tend to be the 589 nm Na I doublet and the 1083 nm metastable helium triplet. Hα and Mg I 457 nm are moderately strong for some planets at some metallicities, but they are almost always optically thin, so some of their emission may not be from the outflow. The planet with the highest-flux, highest-eclipse-depth, and highest-SNR lines is HD 189733b, with a Na I eclipse depth of 410 ppm and SNR of 2.4 per eclipse, and a He* eclipse depth of 170 ppm and SNR of 1.3. These signals would be marginally detectable with Keck if 3–10 eclipses were observed, assuming (over optimistically) photon limited observations.

Keywords: Hydrodynamical simulations, Mini Neptunes, Radiative transfer simulations, Extrasolar gaseous giant planets, Exoplanet atmospheres
Autoencoder Reconstruction of Cosmological Microlensing Magnification Maps. Enhanced modeling of microlensing variations in light curves of strongly lensed quasars improves measurements of cosmological time delays, the Hubble Constant, and quasar structure. Traditional methods for modeling extragalactic microlensing rely on computationally expensive magnification map generation. With large data sets expected from wide-field surveys like the Vera C. Rubin Legacy Survey of Space and Time, including thousands of lensed quasars and hundreds of multiply imaged supernovae, faster approaches become essential. We introduce a deep-learning model that is trained on pre-computed magnification maps covering the parameter space on a grid of κ, γ, and s. Our autoencoder creates a low-dimensional latent space representation of these maps, enabling efficient map generation. Quantifying the performance of magnification map generation from a low dimensional space is an essential step in the roadmap to develop neural network-based models that can replace traditional feed-forward simulation at much lower computational costs. We develop metrics to study various aspects of the autoencoder generated maps and show that the reconstruction is reliable. Even though we observe a mild loss of resolution in the generated maps, we find this effect to be smaller than the smoothing effect of convolving the original map with a source of a plausible size for its accretion disk in the red end of the optical spectrum and larger wavelengths and particularly one suitable for studying the broad-line region of quasars. Used to generate large samples of on-demand magnification maps, our model can enable fast modeling of microlensing variability in lensed quasars and supernovae.

Keywords: Gravitational microlensing, Convolutional neural networks, Quasar microlensing, Neural networks
Little Red Dots: Rapidly Growing Black Holes Reddened by Extended Dusty Flows. The James Webb Space Telescope (JWST) observations have revolutionized extragalactic research, particularly with the discovery of little red dots (LRDs), which have been discovered as a population of dust-reddened broad-line active galactic nuclei (AGNs). Their unique V-shaped spectral feature, characterized by a red optical continuum and a UV excess in the rest frame, challenges us to discern the relative contributions of the galaxy and AGN. We study a spectral energy distribution (SED) model for LRDs from rest-frame UV to infrared bands. We hypothesize that the incident radiation from an AGN, characterized by a typical SED, is embedded in an extended dusty medium with an extinction law similar to those seen in dense regions such as Orion Nebula or certain AGN environments. The UV‑optical spectrum is described by dust-attenuated AGN emission, featuring a red optical continuum at λ &gt; 4000 Å and a flat UV spectral shape established through a gray extinction curve at λ &lt; 3000 Å, due to the absence of small-size grains. There is no need for additional stellar emission or AGN scattered light. In the infrared, the SED is shaped by an extended dust and gas distribution (γ &lt; 1; ρ ∝ r‑γ) with characteristic gas densities of ≃10–103 cm‑3, which allows relatively cool dust temperatures to dominate the radiation. As a result, these dust structures shift the emission energy peak from near-infrared to mid-infrared bands in the rest frame; for sources at z ~ 4–7, the corresponding wavelengths shift from the JWST/MIRI to Herschel range. This model, unlike the typical AGN hot torus models, can produce an infrared SED flattening that is consistent with LRD observations through JWST MIRI. Such a density structure can arise from the coexistence of inflows and outflows during the early assembly of galactic nuclei. This might be the reason why LRDs emerge preferentially in the high-redshift Universe younger than 1 billion years.

Keywords: Supermassive black holes, Galaxy formation, High-redshift galaxies, Quasars
Asymmetries and Circumstellar Interaction in the Type II SN 2024bch. We present a comprehensive multi-epoch photometric and spectroscopic study of SN 2024bch, a nearby (19.9 Mpc) Type II supernova (SN) with prominent early high-ionization emission lines. Optical spectra from 2.8 days after the estimated explosion reveal narrow lines of H I, He II, C IV, and N IV that disappear by day 6. High-cadence photometry from the ground and Transiting Exoplanet Survey Satellite show that the SN brightened quickly and reached a peak MV ~ −17.8 mag within a week of explosion, and late-time photometry suggests a 56Ni mass of 0.050 M⊙. High-resolution spectra from days 7.9 and 43 trace the unshocked circumstellar medium (CSM) and indicate a wind velocity of 30─40 km s−1, a value consistent with a red supergiant (RSG) progenitor. Comparisons between models and the early spectra suggest a pre-SN mass-loss rate of  , which is too high to be explained by quiescent mass loss from RSGs, but is consistent with some recent measurements of similar SNe. Persistent blueshifted H I and [O I] emission lines seen in the optical and near-IR spectra could be produced by asymmetries in the SN ejecta, while the multicomponent Hα may indicate continued interaction with an asymmetric CSM well into the nebular phase. SN 2024bch provides another clue to the complex environments and mass-loss histories around massive stars.

Keywords: Red supergiant stars, Core-collapse supernovae, Type II supernovae, Stellar mass loss, Circumstellar matter
Systematic Search for Long-term Trends in Fermi-LAT Jetted Active Galactic Nuclei. Jetted active galactic nuclei (AGN) exhibit variability across a wide range of timescales. Traditionally, this variability can often be modeled well as a stochastic process. However, in certain cases, jetted AGN variability displays regular patterns, enabling us to conduct investigations aimed at understanding its origins. Additionally, a novel type of variability has emerged in jetted AGN light curves, specifically, the observation of a long-term trend characterized by a linear increase of the flux with time in blazars such as PG 1553+113, which is among the objects most likely to display periodic behavior. In this paper, we present the results of a systematic search for long-term trends, spanning ≈10 yr, utilizing 12 yr of Fermi-LAT observations. The study is focused on detecting the presence of linear or quadratic long-term trends in a sample of 3308 jetted AGN. Our analysis has identified 40 jetted AGN that exhibit long-term trends, each with distinct properties, which we also characterize in this study. These long-term trends may originate from the dynamics of a supermassive black hole binary system, or they could be the result of intrinsic phenomena within the jet itself. Our findings can help in addressing questions pertaining to the astrophysical origins of variability and periodicity within jetted AGN.

Keywords: Active galaxies, BL Lacertae objects, Astronomy data analysis
The Dynamical History of HIP-41378 f—Oblique Exorings Masquerading as a Puffy Planet. The super-puff HIP-41378 f represents a fascinating puzzle due to its anomalously low density on a far-out orbit in contrast with other known super-puffs. In this work, we explore the hypothesis that HIP-41378 f is not in fact a low-density planet, but rather hosts an opaque ring system. We analyze the dynamical history of the system and show that convergent migration is necessary to explain the system's long-term stability. We then show that this same migration process plausibly captures HIP-41378 f into spin–orbit resonance and excites the planetary obliquity to high values. This tilts the surrounding ring and is a plausible explanation for the large transit depth. In the end, we also briefly comment on the likelihood of other super-puff planets being in high-obliquity states. We show that the existence of a tilted extensive ring around a high obliquity planet can serve as an explanation for puffy planets, particularly in multiplanetary systems at far distances from their host stars.

Keywords: Exoplanet dynamics, Spin-orbit resonances
Signatures of Core-envelope Rotational Misalignment in the Mixed-mode Asteroseismology of Kepler-56. Existing asteroseismic rotational measurements assume that stars rotate around a single axis. However, tidal torques from misaligned companions, or their possible engulfment, may bring the rotational axis of a star's envelope out of alignment with its core, breaking azimuthal symmetry. I derive perturbative expressions for asteroseismic signatures of such hitherto unexamined rotational configurations, under the "shellular approximation" of constant rotation rates on radially stratified mass shells. In the aligned case, the distribution of power between multiplet components is determined by the inclination of the rotational axis; radial differential misalignment causes this to vary from multiplet to multiplet. I examine in particular detail the phenomenology of gravitoacoustic mixed modes as seen in evolved sub- and red giants, where near-resonance avoided crossings may break geometrical degeneracies. Upon applying the revised asteroseismic observational methodology that results from this theoretical discussion to revisit Kepler-56—a red giant with a misaligned planetary system—I find that its core and envelope rotate around different rotational axes. While the rotational axis of its core is indeed misaligned from the orbit normal of its transiting planets (consistently with earlier studies), its envelope's rotational axis is close to lying in the sky plane, and may well be aligned with them. More detailed asteroseismic modeling, and spectroscopic follow-up, will be required to fully elucidate the full spin–orbit geometry of the Kepler-56 system, and potentially discriminate between hypotheses for how it formed.

Keywords: Hot Jupiters, Planetary alignment, Exoplanets, Exoplanet formation, Red giant stars, Star-planet interactions, Stellar oscillations, Stellar rotation, Asteroseismology
AEOS: Star-by-star Cosmological Simulations of Early Chemical Enrichment and Galaxy Formation. The AEOS project introduces a series of high-resolution cosmological simulations that model star-by-star chemical enrichment and galaxy formation in the early Universe, achieving 1 pc resolution. These simulations capture the complexities of galaxy evolution within the first ~300 Myr by modeling individual stars and their feedback processes. By incorporating chemical yields from individual stars, AEOS generates galaxies with diverse stellar chemical abundances, linking them to hierarchical galaxy formation and early nucleosynthetic events. These simulations underscore the importance of chemical abundance patterns in ancient stars as vital probes of early nucleosynthesis, star formation histories, and galaxy formation. We examine the metallicity floors of various elements resulting from Population III enrichment, providing best-fit values for eight different metals (e.g., [O/H] = ‑4.0) to guide simulations without Population III models. Additionally, we identify galaxies that begin star formation with Population II after external enrichment and investigate the frequency of carbon-enhanced metal-poor stars at varying metallicities. The AEOS simulations offer detailed insights into the relationship between star formation, feedback, and chemical enrichment. Future work will extend these simulations to later epochs to interpret the diverse stellar populations of the Milky Way and its satellites.

Keywords: Chemical enrichment, Dwarf galaxies, Hydrodynamics, Galaxy chemical evolution
The Magnetic Origin of the Mystery of Rare Hα Moreton Waves. Over the past three decades, a lot of coronal fast-mode waves have been detected by space missions, but their counterparts in the chromosphere, called Moreton waves, have rarely been captured. How this happens remains a mystery. Here, to shed light on this problem, we investigate the photospheric vector magnetograms of the Moreton-wave events associated with M- and X-class solar flares during 2010–2023. The Hα data are taken with the Global Oscillation Network Group and the Chinese Hα Solar Explorer. Our statistical results show that more than 80% of the events occur at the edges of active regions and propagate nonradially, due to asymmetric magnetic fields above the flares. According to the reconstructed magnetic field and atmospheric model, Moreton waves propagate in the direction along which the horizontal fast-mode wave speed drops the fastest. This result supports the inclined magnetic configuration of the eruption being crucial for generating Moreton waves, even for X-class flares. It may explain the low occurrence rate of Moreton waves and why some X-class flares accompanied with coronal mass ejections do not generate Moreton waves.

Keywords: Solar activity, Solar chromosphere, Solar coronal waves, Solar magnetic fields
Revisiting Near-infrared Features of Kilonovae: The Importance of Gadolinium. The observation of the kilonova AT2017gfo and investigations of its light curves and spectra confirmed that neutron star mergers are sites of r-process nucleosynthesis. However, the identification of elements responsible for the spectral features is still challenging, particularly at the near-infrared wavelengths. In this study, we systematically searched for all possible near-infrared transitions of heavy elements using experimentally calibrated energy levels. Our analysis reveals that most candidate elements with strong absorption lines are lanthanides (Z = 57–71) and actinides (Z = 89–103). This is due to their complex structures leading to many low-lying energy levels, which results in strong transitions in the near-infrared range. N. Domoto et al. (2022) have shown that La III and Ce III can explain the absorption features at λ ∼ 12000–15000 Å. While our results confirm that these two elements show strong infrared features, we additionally identify Gd III as the next most promising species. Due to its unique atomic structure involving the half-filled 4f and the outer 5d orbitals, Gd III has one of the lowest-lying energy levels, between which relatively strong transitions occur. We also find absorption lines caused by Gd III in the near-infrared spectrum of a chemically peculiar star HR 465, which supports their emergence in kilonova spectra. By performing radiative transfer simulations, we confirm that Gd III lines affect the feature at ∼12000 Å previously attributed to La III. Future space-based time-series observations of kilonova spectra will allow the identification of Gd III lines.

Keywords: Neutron stars, Spectral line identification, Atomic data, Radiative transfer