Sazuna/UAT_keywords huggingface dataset:
Chemical Abundances of Seven Stars in the GD-1 Stream. We present the first detailed chemical abundances for seven GD-1 stream stars from Subaru/High Dispersion Spectrograph spectroscopy. Atmospheric parameters were derived via color calibrations (Teff) and iterative spectroscopic analysis. LTE abundances for 14 elements (α, odd Z, iron peak, n-capture) were measured. Six stars trace the main orbit; one resides in a "blob." All exhibit tightly clustered metallicities ([Fe/H] = ‑2.38; intrinsic dispersion smaller than 0.05 dex; average uncertainty is about 0.13 dex). While one star shows binary mass transfer signatures, the other six display consistent abundance patterns (dispersions &lt; uncertainties). Their iron-peak elements (Sc, Cr, Mn, Ni) match Milky Way halo stars. In contrast, Y and Sr are systematically lower than halo stars of similar [Fe/H]. Significantly, six stars show consistently enhanced [Eu/Fe] ∼ 0.60 (σ = 0.08). A tight Ba–Eu correlation (r = 0.83, p = 0.04) exists, with [Ba/Fe] = ‑0.03 ± 0.05, indicating a common r-process origin. This extreme chemical homogeneity strongly supports an origin from a single disrupted globular cluster. The lack of light-element anticorrelations may stem from our sample size or the progenitor's low mass.

Keywords: Tidal tails, Chemical abundances, Milky Way Galaxy
Flares on TRAPPIST-1 Reveal the Spectrum of Magnetic Features on Its Surface. TRAPPIST-1 is an M8 dwarf hosting seven known exoplanets and is currently one of the most frequently observed targets of the James Webb Space Telescope (JWST). However, it is notoriously active, and its surface is believed to be covered by magnetic features that contaminate the planetary transmission spectra. The radiative spectra of these magnetic features are needed to clean transmission spectra, but they currently remain unknown. Here, we develop a new approach for measuring these spectra using time-resolved JWST/NIRISS observations. We detect a persistent postflare enhancement in the spectral flux of TRAPPIST-1. Our analysis rules out lingering flare decay as the cause of the flux enhancement and thus, points to structural changes on the stellar surface induced by flares. We suggest that the flaring event triggers the disappearance of (part of) a dark magnetic feature, producing a net brightening. This suggestion is motivated by solar data: flare-induced disappearance of magnetic features on the solar surface has been directly detected in high spatial resolution images, and our analysis shows that this process produces changes in solar brightness very similar to those we observe on TRAPPIST-1. The proposed explanation for the flux enhancement enables, to our knowledge, the first measurement of the spectrum of a magnetic feature on an M8 dwarf. Our analysis indicates that the disappearing magnetic feature is cooler than the TRAPPIST-1 photosphere, but by at most a few hundred kelvins.

Keywords: Starspots, Transmission spectroscopy, Stellar activity, Stellar flares, Stellar faculae
Pivot of the Emerging Bipolar Magnetic Region in the Birth of Sigmoidal Solar Active Regions. We present an augmentation to long-standing evidence from observations and MHD modeling that (1) every solar emerging bipolar magnetic region (BMR) is made by an emerging Ω-loop flux rope, and (2) a twist in the flux-rope field makes the emerged field sigmoidal. Using cotemporal full-disk coronal EUV images, magnetograms, and continuum images from the Solar Dynamics Observatory (SDO), we found and tracked the emergence of 42 emerging single-BMR sigmoidal active regions (ARs) that have sunspots in both polarity domains. Throughout each AR's emergence, we quantified the emerging BMR's tilt angle to the east–west direction (the x-direction in SDO images) by measuring in the continuum images the tilt angle of the line through the (visually located) two centroids of the BMR's opposite-polarity sunspot clusters. As each AR emerges, it becomes either S-shaped (shows net right-handed magnetic twist) or Z-shaped (shows net left-handed magnetic twist) in the coronal EUV images. Nineteen of the ARs become S-shaped, and 23 become Z-shaped. For all 42 ARs, in agreement with published MHD simulations of the emergence of a single-BMR sigmoidal AR from a subsurface twisted flux rope, if the AR becomes S-shaped, the emerging BMR pivots counterclockwise, and if the AR becomes Z-shaped, the emerging BMR pivots clockwise. For our 42 ARs, the pivot amount roughly ranges from 10° to 90° and averages about 35°. Thus, at the onset of the emergence of our average emerging Ω-loop flux rope, the magnetic field's twist pitch angle at the flux rope's top edge is plausibly about 35°.

Keywords: Solar active regions, Solar magnetic flux emergence, Solar magnetic fields
CECILIA: Ultradeep Rest-optical Spectra of Faint Galaxies at Cosmic Noon. Intrinsically faint galaxies at z ∼ 2–3 offer critical insights into early galaxy formation, tracing low-metallicity, low-mass systems during cosmic noon and serving as analogs to reionization-era galaxies. We present ultradeep JWST/NIRSpec spectroscopy of nine low-luminosity galaxies (‑17 ≲ MUV ≲ ‑20, M⋆ ≲ 109 M⊙) at z ∼ 2.5 from the CECILIA program, with ∼29.5 hr in G235M/F170LP and 1 hr in G395M/F290LP. Our sample includes four Lyα emitters, three rest-UV color-selected galaxies, and two serendipitous detections, providing the most sensitive rest-optical spectra of individual faint galaxies at this epoch to date. Balmer-line measurements reveal low star formation rates (SFRs; 0.63 &lt; SFR/(M⊙ yr‑1) &lt; 5.43) and a broad range of dust reddening (0 &lt; E(B ‑ V) &lt; 1), with SFRs systematically below those of continuum-selected galaxies. Electron densities are low (ne ≲ 200 cm‑3), and emission-line diagnostics indicate low [N II]/Hα and high [O III]/Hβ, suggesting metallicities of  12+log(O/H)≲8.0 . We also present the first O1-BPT constraints in such faint high-redshift galaxies. Notably, two galaxies show low [O III]/Hβ despite high Lyα EWs and very low [N II]/Hα, consistent with the predicted turnover in this ratio at very low metallicities, highlighting the need for complementary diagnostics (e.g., N2, O32) to identify metal-poor systems. Direct Te-based abundances and expanded samples are needed to further trace metallicity and ionization trends in low-mass galaxies.

Keywords: Infrared spectroscopy, Dwarf galaxies, Emission line galaxies, James Webb Space Telescope, Lyman-alpha galaxies, Galaxy spectroscopy, High-redshift galaxies, Galaxies
Simultaneously Excited Narrow and Broad Quasiperiodic Fast-propagating Wave Trains in the Solar Corona. The response of a solar coronal plasma loop to an impulsive perturbation, demonstrating the simultaneous formation of guided and leaky fast magnetoacoustic wave trains, is numerically studied. The equilibrium magnetic configuration corresponds to a potential arcade. A loop is modeled by filling a bent magnetic flux bundle with a plasma denser than in the surrounding. The plasma parameter β is much lower than unity everywhere in the computational domain. The initial perturbation is a pulse of the plasma velocity of sausage symmetry. The extent of the velocity pulse along the field is about the minor diameter of the loop. The perturbation generates both a guided fast-mode disturbance along the loop and leaky fast waves that propagate outward into the ambient corona. Both guided and leaky fast waves are quasiperiodic. The external component experiences refraction, which, in the chosen equilibrium, turns the wave toward the vertical. The guided component consists of a leading dispersive precursor, composed predominantly of higher harmonics, followed by a trailing wave train, dominated by the fundamental harmonic. In the external medium, the higher harmonic precursor generates leaky fast perturbations, while perturbations in the trailing wave train are evanescent. Our results confirm that both narrow and broad quasiperiodic fast-propagating waves detected in the corona can be excited by the same spatially localised impulsive energy deposition. The narrow counterpart is associated with the guided component, while the broad component is caused by the leaky component.

Keywords: Solar coronal waves
Supervised Extraction of the Thermal Sunyaev–Zel'dovich Effect with a Three-dimensional Convolutional Neural Network. The thermal Sunyaev–Zel'dovich (SZ) effect offers a unique probe of the hot and diffuse Universe that could help close the missing baryon problem. Traditional extractions of the SZ effect, however, exhibit systematic noise that may lead to unreliable results. In this work, we provide an alternative solution using a 3D attention nested U-Net trained end to end with supervised learning. Our labeled data consist of simulated SZ signals injected into Planck frequency maps, allowing our model to learn how to extract SZ signals in the presence of realistic noise. We implement a curriculum learning scheme that gradually exposed the model to weaker SZ signals. The absence/presence of curriculum learning significantly impacted the amount of bias and variance present in the reconstructed SZ signal. The results from our method were comparable to those from the popular needlet internal linear combination method when evaluated on simulated data as well as real-world SZ signals. We conclude by discussing future avenues for advancing machine learning extractions of SZ signals.

Keywords: Cosmic microwave background radiation, Sunyaev-Zeldovich effect, Astronomical simulations
BASS. XLIX. Characterization of Highly Luminous and Obscured AGNs: Local X-Ray and [Ne V]λ3426 Emission in Comparison with the High-redshift Universe. We present a detailed analysis of the most luminous and obscured active galactic nuclei (AGNs) detected in the ultra-hard X-ray band (14─195 kev) by the Swift/Burst Alert Telescope. Our sample comprises 21 X-ray luminous ( logLX/ergs−1&gt;44.6 , 2─10 keV) AGNs at z &lt; 0.6, optically classified as Seyfert 1.9 and 2. Using NuSTAR, XMM-Newton, Suzaku, and Chandra data, we constrain AGN properties such as absorption column density NH, photon index Γ, intrinsic LX, covering factor, and iron Kα equivalent width. We find median line-of-sight  logNH/cm−2=23.5−1.2+0.5  and 2─10 keV rest-frame, de-absorbed  logLX/ergs−1=44.7−0.6+0.8 , at the 5th and 95th percentiles. For sources with black hole mass estimates (12/20), we find a weak correlation between Γ and Eddington ratio (λEdd). Of these, six (50% ± 13%) lie in the NH-λEdd "forbidden region" and exhibit a combined higher prevalence of NH variability and outflow signatures, suggesting a transitional phase where AGN feedback may be clearing the obscuring material. For the 13/21 sources with multi-epoch X-ray spectroscopy,  85−15+5%  exhibit variability in either 2─10 keV flux ( 77−15+8% ) or line-of-sight NH ( 33−10+15% ). For the 20/21 sources with available near-UV/optical spectroscopy, we detect [Ne v]λ3426 in 17 ( 85−11+5 %), confirming its reliability to probe AGN emission even in heavily obscured systems. When renormalized to the same [O III]λ5007 peak flux as z = 2−9 narrow-line AGNs identified with JWST, our sample exhibits significantly stronger [Ne v]λ3426 emission, suggesting that high-redshift obscured AGNs may be intrinsically weaker in [Ne v]λ3426 or that [Ne v]λ3426 is more challenging to detect in those environments. The sources presented in this work serve as a benchmark for high-redshift analogs, showing the potential of [Ne v]λ3426 to reveal obscured AGNs and the need for future missions to expand X-ray studies into the high-redshift Universe.

Keywords: X-ray astronomy, High-luminosity active galactic nuclei, High energy astrophysics, Active galaxies, James Webb Space Telescope, Seyfert galaxies, X-ray active galactic nuclei, Active galactic nuclei, Galaxy evolution, High-redshift galaxies
Investigating the Impact of Supernova Feedback on Satellites in Elliptical Galaxies. We investigate the influence of supernova (SN) feedback on the satellites of elliptical host galaxies using hydrodynamic simulations. Utilizing a modified version of the GADGET-3 code, we perform cosmological zoom-in simulations of 11 elliptical galaxies with stellar masses in the range 1011M⊙ &lt; M* &lt; 2 × 1011M⊙. We conduct two sets of simulations with identical initial conditions: a fiducial model, which includes a three-phase SN mechanical wind, and a weak SN feedback model, where nearly all SN energy is released as thermal energy with a reduced SN wind velocity. Our comparison shows minimal differences in the elliptical host galaxies, but significant variations in the physical properties of satellite galaxies. The weak SN feedback model produces a larger number of satellite galaxies compared to the fiducial model, and significantly more than observed. For satellite galaxies with stellar masses above 108M⊙, the weak SN feedback model generates approximately 5 times more satellites than observed in the Extending the Satellites Around Galactic Analogs Survey (or xSAGA) survey. Most of these overproduced satellites have small stellar masses, below 1010M⊙. Additionally, satellites in the weak SN feedback model are about 3.5 times more compact than those observed in the SAGA survey and the fiducial model, with metallicities nearly 1 dex higher than observed values. In conclusion, the satellite galaxies in the fiducial model, which includes mechanical SN feedback, exhibit properties that more closely align with observations. This underscores the necessity of incorporating both mechanical active galactic nuclei and SN feedback to reproduce the observed properties of elliptical galaxies and their satellites in simulations.

Keywords: Hydrodynamical simulations, Galaxy formation, Stellar feedback
The Role of Pickup Ions in the Interaction of the Solar Wind with the Local Interstellar Medium. II. Effects of Solar Cycle. We investigate the role of pickup ions (PUIs) in the interaction of a periodically varying solar wind (SW) with the local interstellar medium (LISM). The analysis is performed using a 3D, time-dependent, multifluid model, where PUIs are treated as a separate fluid. The description of PUIs crossing the heliospheric termination shock utilizes results of kinetic simulations incorporated into magnetohydrodynamic (MHD) simulations. Space-time distributions of PUI properties throughout the heliosphere are presented. PUIs exhibit an intriguing behavior in the distant heliotail, where they are mostly concentrated in the vicinity of the heliopause (HP). Our simulations show that, because of the plasma mixing and MHD instabilities, PUIs created in the supersonic SW can cross the HP and enter the LISM. We find that the HP instability and solar cycle cause time-dependent variations in the flow of interstellar neutral atoms. When treated as a separate fluid, PUIs make the heliosphere slimmer, while the SW flow pattern in the heliotail exhibits enhanced variability. The simulation results are validated against in situ observations from the Voyager and New Horizons spacecraft.

Keywords: Heliopause, Space plasmas, Heliosphere, Astrosphere interstellar medium interactions, Termination shock, Solar wind, Interstellar plasma, Pickup ions, Interstellar medium, Heliosheath
Active Galactic Nucleus Feedback-induced Stellar Density Expansion in the Inner Regions of Early-type Galaxies. Observations indicate that early-type galaxies exhibit varying slopes in the relation between their central stellar surface density and stellar mass (Σ1–M⋆). Low-mass galaxies tend to follow a steep slope, close to 1, while the slope flattens for high-mass early-type galaxies. In our study, we investigate the Σ1–M⋆ scaling relation and its evolution using the Numerical Investigation of Hundred Astrophysical Objects (NIHAO) suite of cosmological simulations and compare our findings with recent results from the MaNGA survey. Our analysis shows that NIHAO galaxies successfully reproduce the observed scaling relation based on the MaNGA survey. Our analysis suggests that active galactic nucleus (AGN) feedback plays a critical role in flattening the Σ1 slope, by expelling gas from galactic centers, leading to a decrease in both stellar and dark matter density as the gravitational potential becomes shallower. To further support our findings, we conduct high-resolution N-body simulations, which confirm that (sudden) gas removal does substantially alter the stellar density in the central region, consistent with the results from NIHAO. Furthermore, our numerical experiments show that even if the same amount of gas is reaccreted on a typical (longer) freefall time, it is not able to restore the original stellar density. Our study concludes that AGN-feedback-assisted gas removal presents a plausible explanation for the decline in central stellar surface density as observed in massive elliptical galaxies.

Keywords: Black hole physics, Active galactic nuclei, Galaxy evolution
How Early Could the Milky Way's Disk Form?. We investigate early, z &gt; 3, galaxy formation in a cosmological zoom-in simulation of a close, early-forming Milky Way (MW) analog extracted from TNG50 simulation and resimulated with detailed modeling of cold interstellar medium (ISM) formation, coupled with on-the-fly UV radiative transfer, turbulence-regulated star formation, and stellar feedback. In our enhanced-physics simulation, the galaxy develops a bistable ISM structure (warm, with T ∼ 104 K, and cold, with T &lt; 100 K) and exhibits significantly more efficient, early, and bursty star formation than in TNG. Notably, the stellar disk of this MW progenitor forms extremely early, around z ∼ 6–7, and exhibits chemo-kinematic properties consistent with the low-metallicity population of the MW stars. The disk forms rapidly, on a timescale of ∼0.2 Gyr, which is significantly shorter than the timescale implied by the observable chemo-kinematic signatures of disk spin-up, ∼0.7 Gyr, due to the scatter in the age–metallicity relation. The rotational support of the gas disk and the location of the galaxy on the main sequence are consistent with early disk galaxies observed by the James Webb Space Telescope and the Atacama Large Millimeter/submillimeter Array at z ∼ 4–7, suggesting that some of these galaxies could be progenitors of MW-like systems. Remarkably, the variation of the global star formation rate (SFR) before disk formation is similar to the observed SFR scatter at these early times. Our findings underscore the critical role of modeling a turbulent cold ISM and turbulence-regulated star formation and feedback in driving early SFR variability, while at the same time enabling early disk formation, without destroying it with overly efficient stellar feedback.

Keywords: Early universe, Galaxy formation, Hydrodynamical simulations, Galaxy disks, Milky Way disk, Star formation
Magnetic Effect on the Evolution of an Eccentric and Inclined Orbit. We provide a method to calculate the evolution of an eccentric and inclined orbit under the magnetic effect. Taking the unipolar interaction as an example, we study both coplanar and inclined orbits. We calculate the Lorentz force and then the changes in orbital energy and angular momentum. Combined with the total energy dissipation we write down the evolution equations of semimajor axis, eccentricity, inclination, and spin. This set of equations can be used to study the orbital and spin evolution under the magnetic interaction.

Keywords: Star-planet interactions
Discovery of Diffuse γ-Ray Emission in the Vicinity of G213.0-0.6: Supernova Remnant versus the Massive Star-forming Region. We report the discovery of high-energy γ-ray emission in the vicinity of G213.0-0.6, which is debated as a supernova remnant (SNR) or an ionized hydrogen (HII) region. Using 16 yr Pass 8 data from Fermi Large Area Telescope, we found three extended sources with different photon spectra in this region, which we label as SrcA, SrcB, and SrcC. Among them, the γ-ray source SrcA with a log-parabola spectrum is spatially coincident with a star-forming region and several OB stars. The power-law spectra source SrcB is spatially coincident with an SNR radio shell. SrcC, with a harder power-law photon spectrum, is located outside of the radio shell structure. All of them are spatially coincident with a dense molecular cloud (MC) in the velocity range of 35–54 km s‑1. In this scenario, SrcB can be interpreted as the GeV counterpart of the SNR, and its γ-ray emission originates from the shock–cloud interaction. SrcA and SrcC originate from the escaped CRs illuminating a nearby MC. For SrcA, another possibility is that the γ-ray emission originates from a young stellar cluster associated with a star-forming region; however, the supporting evidence remains insufficient to draw a definitive conclusion.

Keywords: Supernova remnants, Gamma-rays, Interstellar medium
Interband Lag Variability in Active Galactic Nuclei across Zwicky Transient Facility Data from Multiple Years. Interband lags in the optical continua of active galactic nuclei (AGNs) have been observed over years of monitoring, yet their physical origins remain unclear. While variable interband lags have potentially been found in a few individual AGNs, the temporal behavior of the interband lags of an AGN sample has not been explored systematically. Here, we analyze the interband lags of 94 bright AGNs at z &lt; 0.8, using both seasonal 1 yr and full 6 yr gri-band light curves from Zwicky Transient Facility Data Release 22. We find that more than half of the 94 AGNs show significant seasonal variations in the interband lags. Besides, the short-term lags, derived by averaging the lags inferred from multiple seasonal light curves, are consistently smaller than the long-term lags, which are inferred from the full 6 yr light curves. This supports recent theoretical simulations where the lag measurement is sensitive to the baseline of the light curve and the lag variation could be simply attributed to the inherent randomness of AGN variability. Our findings suggest that the interband lags of AGNs are more complex and stochastic than commonly thought, and highlight the importance of high-precision time-domain surveys for uncovering the properties of AGN variability as well as the associated accretion physics.

Keywords: Active galactic nuclei, Time domain astronomy
Unraveling the Role of Neutrino Processes on the Astrophysical Production of <SUP>94</SUP>Mo. The enigmatic origin of the proton-rich nuclei 92Mo and 94Mo in the solar system remains one of the most intriguing mysteries in astrophysics, with the definitive production site yet to be identified. Although mechanisms such as the proton-capture reactions, photonuclear reactions, and neutrino processes have been proposed, the underproduction of 94Mo persists as a puzzle. In this study, we investigate the production of 94Mo through neutrino-induced processes during core-collapse supernova explosions. By calculating the cross sections of the charged-current reactions 94Zr (νe, e‑)94Nb and 95Mo (νe, e‑p)94Mo, as well as the neutral-current reactions 95Mo (ν,ν' n)94Mo, based on supernova explosion models, we explore the contribution of neutrino-nucleus reactions to the abundance of 94Mo. Our results indicate that these neutrino-induced reactions can account for up to 6.8% of the solar system abundance of 94Mo. Additionally, we propose that specific temperatures and proton number densities formed by neutrino shock waves could reproduce the solar system abundance ratio of 94Mo to 92Mo. This work provides a new perspective on understanding the origin of p-process nuclei in the solar system and establishes a significant theoretical foundation for future research endeavors.

Keywords: Solar abundances, Supernova neutrinos, P-process, Core-collapse supernovae