Sazuna/UAT_keywords huggingface dataset:
A Hale-like Cycle in the Solar Twin 18 Scorpii. Characterizing the cyclic magnetic activity of stars that are close approximations of our Sun offers our best hope for understanding our Sun's current and past magnetism, the space weather around solar-type stars, and more generally, the dynamos of other cool stars. The nearest current approximation to the Sun is the solar twin 18 Scorpii, a naked-eye Sun-like star of spectral type G2 Va. However, while 18 Scorpii's physical parameters closely match those of the Sun, its activity cycle is about 7 yr, and shorter than the solar cycle. We report the measurement of a periodicity of 15 yr that corresponds to a longer activity cycle for 18 Scorpii based on observations extending to the last three decades. The global magnetic geometry of 18 Scorpii changes with this 15 yr cycle and appears to be equivalent to the solar 22 yr magnetic polarity cycle. These results suggest that 18 Scorpii is also a magnetic proxy for a younger Sun, adding an important new datum for testing dynamo theory and magnetic evolution of low-mass stars. The results perturb our understanding of the relationship between cycle and rotation, constrain the Sun's magnetism and the Sun-Earth connection over the past billion years, and suggest that solar Schwabe and Hale cycle periods have increased over that time span.

Keywords: Solar cycle, Spectropolarimetry, Solar analogs, Stellar magnetic fields, Stellar evolution
Stellar Outbursts and Chondrite Composition. The temperatures of observed protoplanetary disks are not sufficiently high to produce the accretion rate needed to form stars, nor are they sufficient to explain the volatile depletion patterns in CM, CO, and CV chondrites and terrestrial planets. We revisit the role that stellar outbursts, caused by high-accretion episodes, play in resolving these two issues. These outbursts provide the necessary mass to form the star during the disk lifetime and provide enough heat to vaporize planet-forming materials. We show that these outbursts can reproduce the observed chondrite abundances at distances near 1 au. These outbursts would also affect the growth of calcium-aluminum-rich inclusions and the isotopic compositions of carbonaceous and noncarbonaceous chondrites.

Keywords: Planetary system formation, Dust composition, Protoplanetary disks
A Comparison of Void-finding Algorithms Using Crossing Numbers. We study how well void-finding algorithms identify cosmic void regions and whether we can quantitatively and qualitatively compare the voids they find with dynamical information from the underlying matter distribution. Using the ORIGAMI algorithm to determine the number of dimensions along which dark matter particles have undergone shell crossing (crossing number) in N-body simulations from the AbacusSummit simulation suite, we identify dark matter particles that have undergone no shell crossing as belonging to voids. We then find voids in the corresponding halo distribution using two different void-finding algorithms: VoidFinder and V2, a ZOBOV-based algorithm. The resulting void catalogs are compared to the distribution of dark matter particles to examine how their crossing numbers depend on void proximity. While both algorithms' voids have a similar distribution of crossing numbers near their centers, we find that beyond 0.25 times the effective void radius, voids found by VoidFinder exhibit a stronger preference for particles with low crossing numbers than those found by V2. We examine two possible methods of mitigating this difference in efficacy between the algorithms. While we are able to partially mitigate the ineffectiveness of V2 by using the distance from the void edge as a measure of centrality, we conclude that VoidFinder more reliably identifies dynamically distinct regions of low crossing number.

Keywords: Cosmology, Voids
Early Planet Formation in Embedded Disks (eDisk). VIII. A Small Protostellar Disk around the Extremely Low Mass and Young Class 0 Protostar IRAS 15398-3359. Protostellar disks are an ubiquitous part of the star formation process and the future sites of planet formation. As part of the Early Planet Formation in Embedded Disks large program, we present high angular resolution dust continuum (~40 mas) and molecular line (~150 mas) observations of the Class 0 protostar IRAS 15398-3359. The dust continuum is small, compact, and centrally peaked, while more extended dust structures are found in the outflow directions. We perform a 2D Gaussian fitting and find the deconvolved size and 2σ radius of the dust disk to be 4.5 × 2.8 au and 3.8 au, respectively. We estimate the gas+dust disk mass assuming optically thin continuum emission to be 0.6M J-1.8M J, indicating a very low mass disk. The CO isotopologues trace components of the outflows and inner envelope, while SO traces a compact, rotating disk-like component. Using several rotation curve fittings on the position-velocity diagram of the SO emission, the lower limits of the protostellar mass and gas disk radius are 0.022 M ☉ and 31.2 au, respectively, from our Modified 2 single power-law fitting. A conservative upper limit of the protostellar mass is inferred to be 0.1 M ☉. The protostellar mass accretion rate and the specific angular momentum at the protostellar disk edge are found to be in the range of (1.3-6.1) × 10-6 M ☉ yr-1 and (1.2-3.8) × 10-4 km s-1 pc, respectively, with an age estimated between 0.4 × 104 yr and 7.5 × 104 yr. At this young age with no clear substructures in the disk, planet formation would likely not yet have started. This study highlights the importance of high-resolution observations and systematic fitting procedures when deriving dynamical properties of deeply embedded Class 0 protostars.

Keywords: Observational astronomy, Young stellar objects, Star formation, Circumstellar disks, Stellar accretion disks, Protostars, Radio interferometry, Radio astronomy
FRAMEx. IV. Mechanical Feedback from the Active Galactic Nucleus in NGC 3079. Using the Very Long Baseline Array, we observed the active galactic nucleus (AGN) in NGC 3079 over a span of six months to test for variability in the two main parsec-scale radio components, A and B, which lie on either side of the AGN. We found evidence for positional differences in the positions of A and B over the six months consistent with the apparent motion of these components extrapolated from older archival data, finding that their projected rate of separation, (0.040 ± 0.003)c, has remained constant since ~2004 when a slowdown concurrent with a dramatic brightening of source A occurred. This behavior is consistent with an interaction of source A with the interstellar medium (ISM), as has previously been suggested in the literature. We calculated the amount of mechanical feedback on the ISM for both the scenario in which A is an expulsion of material from the central engine and the scenario in which A is a shock front produced by a relativistic jet, the latter of which is favored by several lines of evidence we discuss. We find that the cumulative mechanical feedback on the ISM is between 2 × 1044 and 1 × 1048 erg for the expulsion scenario or between 3 × 1050 and 1 × 1052 erg for the jet scenario. Integrated over the volume-complete Fundamental Reference AGN Monitoring Experiment (FRAMEx) sample, our results imply that jet-mode mechanical feedback plays a negligible role in the energetics of AGNs in the local Universe.

Keywords: Radio jets, Very long baseline interferometry, X-ray active galactic nuclei, Active galactic nuclei, Radio active galactic nuclei
Identification of Superclusters and Their Properties in the Sloan Digital Sky Survey Using the WHL Cluster Catalog. Superclusters are the largest massive structures in the cosmic web, on tens to hundreds of megaparsec scales. They are the largest assembly of galaxy clusters in the Universe. Apart from a few detailed studies of such structures, their evolutionary mechanism is still an open question. In order to address and answer the relevant questions, a statistically significant, large catalog of superclusters covering a wide range of redshifts and sky areas is essential. Here, we present a large catalog of 662 superclusters identified using a modified friends-of-friends algorithm applied on the WHL (Wen-Han-Liu) cluster catalog within a redshift range of 0.05 ≤ z ≤ 0.42. We name the most massive supercluster at z ~ 0.25 as the Einasto Supercluster. We find that the median mass of superclusters is ~5.8 × 1015 M ☉ and the median size ~65 Mpc. We find that the supercluster environment slightly affects the growth of clusters. We compare the properties of the observed superclusters with the mock superclusters extracted from the Horizon Run 4 cosmological simulation. The properties of the superclusters in the mocks and observations are in broad agreement. We find that the density contrast of a supercluster is correlated with its maximum extent with a power-law index, α ~ -2. The phase-space distribution of mock superclusters shows that, on average, ~90% of part of a supercluster has a gravitational influence on its constituents. We also show the mock halos' average number density and peculiar velocity profiles in and around the superclusters.

Keywords: Galaxy clusters, Superclusters, Catalogs, Large-scale structure of the universe
Inferring Coupling Strengths of Mixed-mode Oscillations in Red Giant Stars Using Deep Learning. Asteroseismology is a powerful tool that may be applied to shed light on stellar interiors and stellar evolution. Mixed modes, behaving like acoustic waves in the envelope and buoyancy modes in the core, are remarkable because they allow for probing the radiative cores and evanescent zones of red giant stars. Here, we have developed a neural network that can accurately infer the coupling strength, a parameter related to the size of the evanescent zone, of solar-like stars in ~5 ms. In comparison with existing methods, we found that only ~43% of inferences were in agreement with a difference less than 0.03 in a sample of ~1700 Kepler red giants. To understand the origin of these differences, we analyzed a few of these stars using independent techniques such as the Monte Carlo Markov Chain method and echelle diagrams. Through our analysis, we discovered that these alternate techniques are supportive of the neural-net inferences. We also demonstrate that the network can be used to yield estimates of coupling strength and period spacing in stars with structural discontinuities. Our findings suggest that the rate of decline in the coupling strength in the red giant branch is greater than previously believed. These results are in closer agreement with calculations of stellar-evolution models than prior estimates, further underscoring the remarkable success of stellar evolution theory and computation. Additionally, we show that the uncertainty in measuring period spacing increases rapidly with diminishing coupling strength.

Keywords: Red giant clump, Asteroseismology, Red giant branch, Neural networks
JWST's TEMPLATES for Star Formation: The First Resolved Gas-phase Metallicity Maps of Dust-obscured Star-forming Galaxies at z ∼ 4. We present the first spatially resolved maps of gas-phase metallicity for two dust-obscured star-forming galaxies at z ~ 4, from the JWST TEMPLATES Early Release Science program, derived from NIRSpec integral field unit spectroscopy of the Hα and [N II] emission lines. Empirical optical line calibrations are used to determine that the sources are globally enriched to near-solar levels. While one source shows elevated [N II]/Hα ratios and broad Hα emission consistent with the presence of an active galactic nucleus in a ≳1 kpc region, we argue that both systems have already undergone significant metal enrichment as a result of their extremely high star formation rates. Utilizing Atacama Large Millimeter/submillimeter Array rest-frame 380 μm continuum and [CI](3P2-3P1) line maps we compare the spatial variation of the metallicity and gas-to-dust ratio in the two galaxies, finding the two properties to be anticorrelated on highly resolved spatial scales, consistent with various literature studies of z ~ 0 galaxies. The data are indicative of the enormous potential of JWST to probe the enrichment of the interstellar medium on ~kpc scales in extremely dust-obscured systems at z ~ 4 and beyond.

Keywords: Starburst galaxies, Galaxy formation, Strong gravitational lensing, Galaxy evolution, High-redshift galaxies
Black Hole Polarimetry I. A Signature of Electromagnetic Energy Extraction. In 1977, Blandford and Znajek showed that the electromagnetic field surrounding a rotating black hole can harvest its spin energy and use it to power a collimated astrophysical jet, such as the one launched from the center of the elliptical galaxy M87. Today, interferometric observations with the Event Horizon Telescope (EHT) are delivering high-resolution, event-horizon-scale, polarimetric images of the supermassive black hole M87* at the jet launching point. These polarimetric images offer an unprecedented window into the electromagnetic field structure around a black hole. In this paper, we show that a simple polarimetric observable-the phase ∠β 2 of the second azimuthal Fourier mode of the linear polarization in a near-horizon image-depends on the sign of the electromagnetic energy flux and therefore provides a direct probe of black hole energy extraction. In Boyer-Lindquist coordinates, the Poynting flux for axisymmetric electromagnetic fields is proportional to the product B  ϕ  B  r . The phase ∠β 2 likewise depends on the ratio B  ϕ /B  r , thereby enabling an observer to determine the direction of electromagnetic energy flow in the near-horizon environment experimentally. Data from the 2017 EHT observations of M87* are consistent with electromagnetic energy outflow. Currently envisioned multifrequency observations of M87* will achieve higher dynamic range and angular resolution, and hence deliver measurements of ∠β 2 closer to the event horizon as well as better constraints on Faraday rotation. Such observations will enable a definitive test for energy extraction from the black hole M87*.

Keywords: Accretion, Supermassive black holes, Magnetohydrodynamics, Black hole physics, Black holes, Very long baseline interferometry, Relativistic jets, Event horizons, Magnetohydrodynamical simulations
An X-Ray Census of Fast Radio Burst Host Galaxies: Constraints on Active Galactic Nuclei and X-Ray Counterparts. We present the first X-ray census of fast radio burst (FRB) host galaxies to conduct the deepest search for active galactic nuclei (AGN) and X-ray counterparts to date. Our sample includes seven well-localized FRBs with unambiguous host associations and existing deep Chandra observations, including two events for which we present new observations. We find evidence for AGN in two FRB host galaxies based on the presence of X-ray emission coincident with their centers, including the detection of a luminous (L  X  ≈ 5 × 1042 erg s-1) X-ray source at the nucleus of FRB 20190608B's host, for which we infer an SMBH mass of M BH ~ 108 M ⊙ and an Eddington ratio L bol/L Edd ≈ 0.02, characteristic of geometrically thin disks in Seyfert galaxies. We also report nebular emission-line fluxes for 24 highly secure FRB hosts (including 10 hosts for the first time), and assess their placement on a BPT diagram, finding that FRB hosts trace the underlying galaxy population. We further find that the hosts of repeating FRBs are not confined to the star-forming locus, contrary to previous findings. Finally, we place constraints on associated X-ray counterparts to FRBs in the context of ultraluminous X-ray sources (ULXs), and find that existing X-ray limits for FRBs rule out ULXs brighter than L  X  ≳ 1040 erg s-1. Leveraging the CHIME/FRB catalog and existing ULX catalogs, we search for spatially coincident ULX-FRB pairs. We identify a total of 28 ULXs spatially coincident with the localization regions for 17 FRBs, but find that the DM-inferred redshifts for the FRBs are inconsistent with the ULX redshifts, disfavoring an association between these specific ULX-FRB pairs.

Keywords: AGN host galaxies, Ultraluminous x-ray sources, Active galactic nuclei, Radio transient sources
Extreme Red-wing Enhancements of UV Lines during the 2022 March 30 X1.3 Solar Flare. Here, we present the study of a compact emission source during an X1.3 flare on 2022 March 30. Within a ~41 s period (17:34:48 UT to 17:35:29 UT), Interface Region Imaging Spectrograph observations show spectral lines of Mg II, C II, and Si IV with extremely broadened, asymmetric red wings. This source of interest (SOI) is compact, ~1.″6, and is located in the wake of a passing ribbon. Two methods were applied to measure the Doppler velocities associated with these red wings: spectral moments and multi-Gaussian fits. The spectral-moments method considers the averaged shift of the lines, which are 85, 125, and 115 km s-1 for the Mg II, C II, and Si IV lines respectively. The red-most Gaussian fit suggests a Doppler velocity up to ~160 km s-1 in all of the three lines. Downward mass motions with such high speeds are very atypical, with most chromospheric downflows in flares on the order 10-100 km s-1. Furthermore, extreme-UV (EUV) emission is strong within flaring loops connecting two flare ribbons located mainly to the east of the central flare region. The EUV loops that connect the SOI and its counterpart source in the opposite field are much less brightened, indicating that the density and/or temperature is comparatively low. These observations suggest a very fast downflowing plasma in the transition region and upper chromosphere, which decelerates rapidly since there is no equivalently strong shift of the O I chromospheric lines. This unusual observation presents a challenge that models of the solar atmosphere's response to flares must be able to explain.

Keywords: Solar flares, Solar flare spectra, Solar transition region, Solar chromosphere, Active solar chromosphere
Characterizing the Atmospheric Dynamics of HD 209458b-like Hot Jupiters Using AI-driven Image Recognition/Categorization. In order to understand the results of recent observations of exoplanets, models have become increasingly complex. Unfortunately, this increases both the computational cost and output size of said models. We intend to explore if AI image recognition can alleviate this burden. We used DYNAMICO to run a series of HD 209458-like models with different orbital radii. Training data for a number of features of interest was selected from the initial outputs of these models. This was used to train a pair of multi-categorization convolutional neural networks (CNNs), which we applied to our outer-atmosphere-equilibrated models. The features detected by our CNNs revealed that our models fall into two regimes: models with shorter orbital radii exhibit significant global mixing that shapes the dynamics of the entire atmosphere, whereas models with longer orbital-radii exhibit negligible mixing except at mid-pressures. Here the initial nondetection of any trained features revealed a surprise: a nightside hot spot. Analysis suggests that this occurs when rotational influence is sufficiently weak that divergent flows from the dayside to the nightside dominate over rotational-driven transport, such as the equatorial jet. We suggest that image classification may play an important role in future, computational, atmospheric studies. However special care must be paid to the data feed into the model, from the color map, to training the CNN on features with enough breadth and complexity that the CNN can learn to detect them. However, by using preliminary studies and prior models, this should be more than achievable for future exascale calculations, allowing for a significant reduction in future workloads and computational resources.

Keywords: Exoplanet atmospheres, Exoplanet atmospheric structure
A New Index to Describe the Relationship between Solar Extreme Ultraviolet Variation and Solar Activity. In this paper, a new solar activity index based on a novel disturbance extraction method, the spectral whitening method (SWM), is introduced to process the solar EUV data on the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. Our research suggests that the spatial information derived by SWM can well reflect the location of disturbance extraction, which is consistent with the location of the solar active region. It indicates that the disturbance extraction is effective. From AIA 094 Å to AIA 335 Å, SWM results are strongly correlated with solar radio flux F107 and the sunspot number (SSN), especially at AIA 211 Å, where the correlation coefficient reaches the maximum, while at AIA 1600 Å and AIA 1700 Å there are no detectable correlations. The proposed new solar activity index, ${J}_{P}\left(\mathrm{AIA}\right)$ , has the following characteristics: (1) the new index can reflect the main variations of F107 and SSN, indicating that the index is valid; (2) the new index has higher temporal resolution, which is more conducive to the more detailed study of solar activities on short timescales; (3) the new index reveals that the solar atmosphere still has significant variability during solar minimum characterized by low F107 and SSN; (4) the new index can be used in conjunction with the new magnetospheric and ionospheric indices, which are also derived by SWM to deepen the understanding of the causal chain of space weather and promote the improvement of forecasting capabilities.

Keywords: Solar activity
Relation between Latitude-dependent Sunspot Data and Near-Earth Solar Wind Speed. Solar wind is important for the space environment between the Sun and the Earth and varies with the sunspot cycle, which is influenced by solar internal dynamics. We study the impact of latitude-dependent sunspot data on solar wind speed using the Granger causality test method and a machine-learning prediction approach. The results show that the low-latitude sunspot number has a larger effect on the solar wind speed. The time delay between the annual average solar wind speed and sunspot number decreases as the latitude range decreases. A machine-learning model is developed for the prediction of solar wind speed considering latitude and time effects. It is found that the model performs differently with latitude-dependent sunspot data. It is revealed that the timescale of the solar wind speed is more strongly influenced by low-latitude sunspots and that sunspot data have a greater impact on the 30 day average solar wind speed than on a daily basis. With the addition of sunspot data below 7.°2 latitude, the prediction of the daily and 30 day averages is improved by 0.23% and 12%, respectively. The best correlation coefficient is 0.787 for the daily solar wind prediction model.

Keywords: Space weather