Sazuna/UAT_keywords huggingface dataset:
SBI<SUP>++</SUP>: Flexible, Ultra-fast Likelihood-free Inference Customized for Astronomical Applications. Flagship near-future surveys targeting 108-109 galaxies across cosmic time will soon reveal the processes of galaxy assembly in unprecedented resolution. This creates an immediate computational challenge on effective analyses of the full data set. With simulation-based inference (SBI), it is possible to attain complex posterior distributions with the accuracy of traditional methods but with a &gt;104 increase in speed. However, it comes with a major limitation. Standard SBI requires the simulated data to have characteristics identical to those of the observed data, which is often violated in astronomical surveys due to inhomogeneous coverage and/or fluctuating sky and telescope conditions. In this work, we present a complete SBI-based methodology, SBI  ++ , for treating out-of-distribution measurement errors and missing data. We show that out-of-distribution errors can be approximated by using standard SBI evaluations and that missing data can be marginalized over using SBI evaluations over nearby data realizations in the training set. In addition to the validation set, we apply SBI  ++  to galaxies identified in extragalactic images acquired by the James Webb Space Telescope, and show that SBI  ++  can infer photometric redshifts at least as accurately as traditional sampling methods-and crucially, better than the original SBI algorithm using training data with a wide range of observational errors. SBI  ++  retains the fast inference speed of ~1 s for objects in the observational training set distribution, and additionally permits parameter inference outside of the trained noise and data at ~1 minute per object. This expanded regime has broad implications for future applications to astronomical surveys. (Code and a Jupyter tutorial are made publicly available at https://github.com/wangbingjie/sbi_pp.)

Keywords: Computational astronomy, Algorithms, Astrostatistics
Kinetic Features of Alpha Particles in a Pestchek-like Magnetic Reconnection Event in the Solar Wind Observed by Solar Orbiter. The acceleration and heating of solar wind particles by magnetic reconnection are important mechanisms in space physics. Although alpha particles (4He2+) are the second most abundant population of solar wind ions, their kinetic behavior in solar wind magnetic reconnection is not well understood. Using the high-energy (1500-3000 eV) range of the Solar Wind Analyser/Proton-Alpha Sensor instrument on board Solar Orbiter, we study the kinetic features of alpha particles in an exhaust region of a Pestchek-like solar-wind reconnection event with a weak guide field. A pair of back-to-back compound discontinuities is observed in the exhaust region. We find that the plasma in the magnetic exhaust region is heated and bounded by slow shocks (SSs), while the accelerated reconnection jet is bounded by rotational discontinuities (RDs). The SSs are outside the RDs, which is not expected from the magnetohydrodynamical prediction. We suggest this different location of the discontinuities is due to the enhanced parallel temperature T  p∥ &gt; T  p⊥, which reduces the local Alfvén speed in the exhaust region, allowing the SSs to propagate faster than the RDs. Inside the exhaust region, the guide field is dominant. We find a two-population distribution of the alpha particles. These two populations are field aligned downstream the SSs and shift to have a perpendicular offset in the reconnection jet, suggesting that the change of the magnetic field at the RDs has similar timescales with the proton gyroperiod, but faster than those of the alpha particles, such that the alpha particles behave like pickup ions.

Keywords: Solar wind, Solar magnetic reconnection, Heliosphere
The Dimorphos Boulder Swarm. We present deep Hubble Space Telescope images taken to examine the ejecta from the DART spacecraft impact into asteroid Dimorphos. The images reveal an extensive population of comoving boulders, the largest of which is ~7 m in diameter (geometric albedo 0.15 assumed). Measurements of 37 boulders show a mean sky-plane velocity dispersion of 0.30 ± 0.03 m s-1, only slightly larger than the 0.24 m s-1 gravitational escape velocity from the Didymos-Dimorphos binary system. The total boulder mass, M  b  ~ 5 × 106 kg (density 2200 kg m-3 assumed), corresponds to about 0.1% of the mass of Dimorphos, and the boulders collectively carry about 3 × 10-5 of the kinetic energy delivered by the DART spacecraft impact. The sky-plane distribution of the boulders is asymmetric, consistent with impact into an inhomogeneous, likely rubble-pile, body. Surface boulder counts on Didymos show that the observed boulder swarm could be ejected from as little as 2% of the surface of Dimorphos (for example, a circular crater at the impact point about 50 m in diameter). The large, slow-moving boulders are potential targets to be investigated in situ by the upcoming ESA HERA mission.

Keywords: Impact phenomena, Near-Earth objects, Asteroids, Solar system astronomy
What Do Halo CMEs Tell Us about Solar Cycle 25?. It is known that the weak state of the heliosphere due to diminished solar activity in cycle 24 backreacted on coronal mass ejections (CMEs) to make them appear wider for a given speed. One of the consequences of the weak state of the heliosphere is that more CMEs appear as halo CMEs (HCMEs), and halos are formed at shorter heliocentric distances. Current predictions for the strength of solar cycle (SC) 25 range from half to twice the strength of SC 24. We compare the HCME occurrence rate and other properties during the rise phase of cycles 23, 24, and 25 to weigh in on the strength of SC 25. We find that HCME and solar wind properties in SC 25 are intermediate between SCs 23 and 24, but closer to SC 24. The HCME occurrence rate, normalized to the sunspot number, is higher in SCs 24 and 25 than in SC 23. The solar wind total pressure in SC 25 is ~35% smaller than that in SC 23. Furthermore, the occurrence rates of high-energy solar energetic particle events and intense geomagnetic storms are well below the corresponding values in SC 23, but similar to those in SC 24. We conclude that cycle 25 is likely to be similar to or slightly stronger than cycle 24, in agreement with polar-field precursor methods for cycle 25 prediction.

Keywords: Solar coronal mass ejections
Early Results from GLASS-JWST. XXII. Rest-frame UV-Optical Spectral Properties of Lyα Emitting Galaxies at 3 &lt; z &lt; 6. Lyα emission is possibly the best indirect diagnostic of Lyman continuum (LyC) escape since the conditions that favor the escape of Lyα photons are often the same that allow for the escape of LyC photons. In this work, we present the rest-frame UV-optical spectral characteristics of 11 Lyα emitting galaxies at 3 &lt; z &lt; 6-the redshift range that optimizes between intergalactic medium attenuation effects and temporal proximity to the epoch of reionization. From a combined analysis of JWST/NIRSpec and MUSE data, we present the Lyα escape fraction and study its correlation with other physical properties of galaxies that might facilitate Lyα escape. We find that our galaxies have low masses (80% of the sample with ${\mathrm{log}}_{10}\ {M}_{\star }\lt 9.5\ {M}_{\odot }$ ), compact sizes (median R  e  ~ 0.7 kpc), low dust content, moderate [O III]/[O II] flux ratios (mean ~ 6.8 ± 1.2), and moderate Lyα escape fractions (mean ${f}_{\mathrm{esc}}^{\mathrm{Ly}\alpha }\ \sim $ 0.11). Our sample shows characteristics that are broadly consistent with low-redshift galaxies with Lyα emission, which are termed as "analogs" of the high-redshift population. We predict the LyC escape fraction in our sample to be low (0.03-0.07), although larger samples in the postreionization epoch are needed to confirm these trends.

Keywords: Lyman-alpha galaxies, High-redshift galaxies, Galaxies
The Role of High-frequency Transverse Oscillations in Coronal Heating. Transverse oscillations that do not show significant damping in solar coronal loops are found to be ubiquitous. Recently, the discovery of high-frequency transverse oscillations in small-scale loops has been accelerated by the Extreme Ultraviolet Imager on board Solar Orbiter. We perform a meta-analysis by considering the oscillation parameters reported in the literature. Motivated by the power law of the velocity power spectrum of propagating transverse waves detected with CoMP, we consider the distribution of energy fluxes as a function of oscillation frequencies and the distribution of the number of oscillations as a function of energy fluxes and energies. These distributions are described as a power law. We propose that the power-law slope (δ = -1.40) of energy fluxes depending on frequencies could be used for determining whether high-frequency oscillations dominate the total heating (δ &lt; 1) or not (δ &gt; 1). In addition, we found that the oscillation number distribution depending on energy fluxes has a power-law slope of α = 1.00, being less than 2, which means that oscillations with high energy fluxes provide the dominant contribution to the total heating. It is shown that, on average, higher energy fluxes are generated from higher-frequency oscillations. The total energy generated by transverse oscillations ranges from about 1020 to 1025 erg, corresponding to the energies for nanoflare (1024-1027 erg), picoflare (1021-1024 erg), and femtoflare (1018-1021 erg). The respective slope results imply that high-frequency oscillations could provide the dominant contribution to total coronal heating generated by decayless transverse oscillations.

Keywords: Solar oscillations, Solar coronal heating, Solar coronal waves
Isotopic Enrichment of Planetary Systems from Asymptotic Giant Branch Stars. Short-lived radioisotopes, in particular 26Al and 60Fe, are thought to contribute to the internal heating of the Earth, but are significantly more abundant in the solar system compared to the interstellar medium. The presence of their decay products in the oldest solar system objects argues for their inclusion in the Sun's protoplanetary disk almost immediately after the star formation event that formed the Sun. Various scenarios have been proposed for their delivery to the solar system, usually involving one or more core-collapse supernovae of massive stars. An alternative scenario involves the young Sun encountering an evolved asymptotic giant branch (AGB) star. AGBs were previously discounted as a viable enrichment scenario for the solar system due to the presumed low probability of an encounter between an old, evolved star and a young pre-main-sequence star. We report the discovery in Gaia data of an interloping AGB star in the star-forming region NGC2264, demonstrating that old, evolved stars can encounter young forming planetary systems. We use simulations to calculate the yields of 26Al and 60Fe from AGBs and their contribution to the long-term geophysical heating of a planet, and find that these are comfortably within the range previously calculated for the solar system.

Keywords: Asymptotic giant branch stars, Solar system formation, Star forming regions
Spirals and Clumps in V960 Mon: Signs of Planet Formation via Gravitational Instability around an FU Ori Star?. The formation of giant planets has traditionally been divided into two pathways: core accretion and gravitational instability. However, in recent years, gravitational instability has become less favored, primarily due to the scarcity of observations of fragmented protoplanetary disks around young stars and the low occurrence rate of massive planets on very wide orbits. In this study, we present a SPHERE/IRDIS polarized light observation of the young outbursting object V960 Mon. The image reveals a vast structure of intricately shaped scattered light with several spiral arms. This finding motivated a reanalysis of archival Atacama Large Millimeter/submillimeter Array 1.3 mm data acquired just two years after the onset of the outburst of V960 Mon. In these data, we discover several clumps of continuum emission aligned along a spiral arm that coincides with the scattered light structure. We interpret the localized emission as fragments formed from a spiral arm under gravitational collapse. Estimating the mass of solids within these clumps to be of several Earth masses, we suggest this observation to be the first evidence of gravitational instability occurring on planetary scales. This study discusses the significance of this finding for planet formation and its potential connection with the outbursting state of V960 Mon.

Keywords: Observational astronomy, Gravitational instability, Planet formation, FU Orionis stars
Volatile-to-sulfur Ratios Can Recover a Gas Giant's Accretion History. The newfound ability to detect SO2 in exoplanet atmospheres presents an opportunity to measure sulfur abundances and so directly test between competing modes of planet formation. In contrast to carbon and oxygen, whose dominant molecules are frequently observed, sulfur is much less volatile and resides almost exclusively in solid form in protoplanetary disks. This dichotomy leads different models of planet formation to predict different compositions of gas giant planets. Whereas planetesimal-based models predict roughly stellar C/S and O/S ratios, pebble-accretion models more often predict superstellar ratios. To explore the detectability of SO2 in transmission spectra and its ability to diagnose planet formation, we present a grid of atmospheric photochemical models and corresponding synthetic spectra for WASP-39b (where SO2 has been detected). Our 3D grid contains 113 models (spanning 1-100× the solar abundance ratio of C, O, and S) for thermal profiles corresponding to the morning and evening terminators, as well as mean terminator transmission spectra. Our models show that for a WASP-39b-like O/H and C/H enhancement of ~10× solar, SO2 can only be seen for C/S and O/S ≲ 1.5× solar, and that WASP-39b's reported SO2 abundance of 1-10 ppm may be more consistent with planetesimal accretion than with pebble-accretion models (although some pebble models also manage to predict similarly low ratios). More extreme C/S and O/S ratios may be detectable in higher-metallicity atmospheres, suggesting that smaller and more metal-rich gas and ice giants may be particularly interesting targets for testing planet formation models. Future studies should explore the dependence of SO2 on a wider array of planetary and stellar parameters, both for the prototypical SO2 planet WASP-39b, as well as for other hot Jupiters and smaller gas giants.

Keywords: Exoplanet atmospheric composition , Astronomy data modeling, Infrared spectroscopy, Molecular spectroscopy, Chemical abundances, James Webb Space Telescope, Exoplanet formation, Exoplanet atmospheres
SO and SiS Emission Tracing an Embedded Planet and Compact <SUP>12</SUP>CO and <SUP>13</SUP>CO Counterparts in the HD 169142 Disk. Planets form in dusty, gas-rich disks around young stars, while at the same time, the planet formation process alters the physical and chemical structure of the disk itself. Embedded planets will locally heat the disk and sublimate volatile-rich ices, or in extreme cases, result in shocks that sputter heavy atoms such as Si from dust grains. This should cause chemical asymmetries detectable in molecular gas observations. Using high-angular-resolution ALMA archival data of the HD 169142 disk, we identify compact SO J = 88 - 77 and SiS J = 19 - 18 emission coincident with the position of a ~ 2 M Jup planet seen as a localized, Keplerian NIR feature within a gas-depleted, annular dust gap at ≈38 au. The SiS emission is located along an azimuthal arc and has a morphology similar to that of a known 12CO kinematic excess. This is the first tentative detection of SiS emission in a protoplanetary disk and suggests that the planet is driving sufficiently strong shocks to produce gas-phase SiS. We also report the discovery of compact 12CO and 13CO J = 3 - 2 emission coincident with the planet location. Taken together, a planet-driven outflow provides the best explanation for the properties of the observed chemical asymmetries. We also resolve a bright, azimuthally asymmetric SO ring at ≈24 au. While most of this SO emission originates from ice sublimation, its asymmetric distribution implies azimuthal temperature variations driven by a misaligned inner disk or planet-disk interactions. Overall, the HD 169142 disk shows several distinct chemical signatures related to giant planet formation and presents a powerful template for future searches of planet-related chemical asymmetries in protoplanetary disks.

Keywords: Planetary-disk interactions, Planet formation, Astrochemistry, Protoplanetary disks, High angular resolution
Small Planets around Cool Dwarfs: Enhanced Formation Efficiency of Super-Earths around M Dwarfs. Current measurements of planet population as a function of stellar mass show three seemingly contradictory signatures: close-in super-Earths are more prevalent around M dwarfs than FGK dwarfs; inner super-Earths are correlated with outer giants; and outer giants are less common around M dwarfs than FGK dwarfs. Here, we build a simple framework that combines the theory of pebble accretion with the measurements of dust masses in protoplanetary disks to reconcile all three observations. First, we show that cooler stars are more efficient at converting pebbles into planetary cores at short orbital periods. Second, when disks are massive enough to nucleate a heavy core at 5 au, more than enough dust can drift in to assemble inner planets, establishing the correlation between inner planets and outer giants. Finally, while stars of varying masses are similarly capable of converting pebbles into cores at long orbital periods, hotter stars are much more likely to harbor more massive dust disks so that the giant planet occurrence rate rises around hotter stars. Our results are valid over a wide range of parameter space for a disk accretion rate that follows ${\dot{M}}_{\star }\sim {10}^{-8}\,{M}_{\odot }\,{\mathrm{yr}}^{-1}{({M}_{\star }/{M}_{\odot })}^{2}$ . We predict a decline in mini-Neptune population (but not necessarily terrestrial planets) around stars lighter than ~0.3-0.5M ⊙. Cold giants (≳5 au), if they exist, should remain correlated with inner planets even around lower-mass stars.

Keywords: Super Earths, Extrasolar gaseous giant planets, Planet formation
Confronting the Neutron Star Population with Inverse Cascades. The origin and evolution of magnetic fields of neutron stars from birth have long been a source of debate. Here, motivated by recent simulations of the Hall cascade with magnetic helicity, we invoke a model where the large-scale magnetic field of neutron stars grows as a product of small-scale turbulence through an inverse cascade. We apply this model to a simulated population of neutron stars at birth and show how this model can account for the evolution of such objects across the $P\dot{P}$ diagram, explaining both pulsar and magnetar observations. Under the assumption that small-scale turbulence is responsible for large-scale magnetic fields, we place a lower limit on the spherical harmonic degree of the energy-carrying magnetic eddies of ≈40. Our results favor the presence of a highly resistive pasta layer at the base of the neutron star crust. We further discuss the implications of this paradigm on direct observables, such as the nominal age and braking index of pulsars.

Keywords: Neutron stars, Magnetars, Pulsars
The Structure of Coronal Mass Ejections Recorded by the K-Coronagraph at Mauna Loa Solar Observatory. Previous survey studies reported that coronal mass ejections (CMEs) can exhibit various structures in white-light coronagraphs, and ~30% of them have the typical three-part feature in the high corona (e.g., 2-6 R ☉), which has been taken as the prototypical structure of CMEs. It is widely accepted that CMEs result from eruption of magnetic flux ropes (MFRs), and the three-part structure can be understood easily by means of the MFR eruption. It is interesting and significant to answer why only ~30% of CMEs have the three-part feature in previous studies. Here we conduct a synthesis of the CME structure in the field of view (FOV) of K-Coronagraph (1.05-3 R ☉). In total, 369 CMEs are observed from 2013 September to 2022 November. After inspecting the CMEs one by one through joint observations of the Atmospheric Imaging Assembly, K-Coronagraph, and LASCO/C2, we find 71 events according to the criteria: (1) limb event; (2) normal CME, i.e., angular width ≥30°; (3) K-Coronagraph caught the early eruption stage. All (or more than 90% considering several ambiguous events) of the 71 CMEs exhibit the three-part feature in the FOV of K-Coronagraph, while only 30%-40% have the feature in the C2 FOV (2-6 R ☉). For the first time, our studies show that 90%-100% and 30%-40% of normal CMEs possess the three-part structure in the low and high corona, respectively, which demonstrates that many CMEs can lose the three-part feature during their early evolutions, and strongly supports that most (if not all) CMEs have the MFR structures.

Keywords: Solar activity, Solar prominences, Solar coronal mass ejections
SN 2023ixf in Messier 101: A Variable Red Supergiant as the Progenitor Candidate to a Type II Supernova. We present preexplosion optical and infrared (IR) imaging at the site of the type II supernova (SN II) 2023ixf in Messier 101 at 6.9 Mpc. We astrometrically registered a ground-based image of SN 2023ixf to archival Hubble Space Telescope (HST), Spitzer Space Telescope (Spitzer), and ground-based near-IR images. A single point source is detected at a position consistent with the SN at wavelengths ranging from HST R band to Spitzer 4.5 μm. Fitting with blackbody and red supergiant (RSG) spectral energy distributions (SEDs), we find that the source is anomalously cool with a significant mid-IR excess. We interpret this SED as reprocessed emission in a 8600 R ☉ circumstellar shell of dusty material with a mass ~5 × 10-5 M ☉ surrounding a $\mathrm{log}(L/{L}_{\odot })=4.74\pm 0.07$ and ${T}_{\mathrm{eff}}={3920}_{-160}^{+200}$ K RSG. This luminosity is consistent with RSG models of initial mass 11 M ☉, depending on assumptions of rotation and overshooting. In addition, the counterpart was significantly variable in preexplosion Spitzer 3.6 and 4.5 μm imaging, exhibiting ~70% variability in both bands correlated across 9 yr and 29 epochs of imaging. The variations appear to have a timescale of 2.8 yr, which is consistent with κ-mechanism pulsations observed in RSGs, albeit with a much larger amplitude than RSGs such as α Orionis (Betelgeuse).

Keywords: Type II supernovae, Stellar evolution
The Luminosity-Area Relation of z &gt; 2 Quasars' Lyα Nebulae. Cool (T ~ 104 K) gas is commonly observed around z &gt; 2 quasars as traced by extended Lyα emission. These large-scale nebulae are usually studied using circularly averaged surface-brightness profiles, which suppress information on morphological differences. Here, we revisit the Lyα nebulae around 78 z ~ 2-3 quasars to obtain a novel estimate of their area and asymmetry using a common redshift-corrected surface-brightness threshold. We find a luminosity-area relation of the form $\mathrm{log}({L}_{\mathrm{Ly}\alpha }^{\mathrm{Neb}})={a}_{1}\mathrm{log}({\mathrm{Area}}^{\mathrm{Neb}})+{a}_{0}$ . Most nebulae are symmetric and bright, the most lopsided ones being the faintest and less extended. The enormous Lyα nebulae, asymmetric due to the presence of active companions, are the exceptions to this trend. By using simulations able to reproduce z ~ 6 quasars' nebulae, we show that the observed relation should not vary with redshift. Finally, we discuss possible mechanisms that drive the relation and future work needed to constrain them.

Keywords: Extended radiation sources, High-redshift galaxies, Circumgalactic medium, Quasars