Sazuna/UAT_keywords huggingface dataset:
Disentangling the Hemispheres of Teegarden's Star b with LIFE. Teegarden's Star is one of the most promising targets for the first observations of LIFE as a nontransiting rocky planet with similar bulk properties to the Earth and a relatively quiescent M dwarf host star. We use LIFEsim, a software developed by the LIFE team based in ETH Zurich, along with thermal emission maps obtained from a suite of three-dimensional global climate model simulations, to explore the sensitivity of LIFE to the observation geometry. We find that 3 days of observation in broad band would be enough to disentangle the hemispheres of the planet with a 1σ or 3σ confidence level with a baseline or optimistic scenario, respectively. Doing the same for a fast rotator in the habitable zone of a G-class star would be prohibitively challenging. Given enough observation time, the sensitivity of LIFE may allow some spatial resolution of Teegarden's Star b to be achieved, which may directly link to the presence of water clouds and therefore an active hydrology.

Keywords: Extrasolar rocky planets, Astrobiology, Habitable planets
Accretion is All You Need: Black Hole Spin Alignment in Merger GW231123 Indicates Accretion Pathway. GW231123 represents the most massive binary─black hole merger detected to date, lying firmly within, or even above, the pair-instability mass gap. The component spins are both exceptionally high ( a1=0.90−0.19+0.10 ,  a2=0.80−0.51+0.20 ), which is difficult to explain with repeated mergers. Here we show that the black hole spin vectors are closely aligned with each other while significantly tilted relative to the binary's orbital angular momentum, pointing to a common accretion-driven origin. We examine astrophysical formation channels capable of producing near-equal, high-mass, and mutually aligned spins consistent with GW231123—particularly binaries embedded in AGN disks and Population III remnants, which grew via coherent misaligned gas accretion. We further argue that other high-mass, high-spin events, e.g., GW190521, may share a similar evolutionary pathway. These findings underscore the critical role of sustained, coherent accretion in shaping the most extreme black hole binaries.

Keywords: Gravitational waves
Primary Beam Chromaticity in HIRAX. I. Characterization from Simulations and Power Spectrum Implications. The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is an upcoming radio interferometric telescope designed to constrain dark energy through the 21 cm intensity mapping of baryon acoustic oscillations. Instrumental systematics must be controlled and carefully characterized to measure the 21 cm power spectrum with fidelity and achieve high-precision constraints on the cosmological parameters. The chromaticity of the primary beam is one such complicated systematic, which can leak the power of spectrally smooth foregrounds beyond the ideal horizon limits due to the complex spatial and spectral structures of the side lobes and the main lobe. This paper investigates the chromaticity of the HIRAX Stokes I primary beam and its impact on the accurate measurement of the 21 cm power spectrum. To investigate the effect of chromaticity on the 21 cm power spectrum, we present a physically motivated beam modeling technique that utilizes a flexible basis derived from traditional optics, allowing for the accounting of higher-order radial and azimuthal structures in the primary beam. We investigate the impact of imperfect knowledge of the main lobe and side lobes' chromaticity in the power spectrum space by subtracting a simple foreground model in simulated snapshot visibilities to recover the H I power spectrum. Additionally, we find that modeling up to the octupolar azimuthal order feature (fourth-order angular variation) in the primary beam is sufficient to reduce the leakage outside the wedge with minimal bias.

Keywords: Observational cosmology, H I line emission, Radio telescopes, Cosmological constant, Radio interferometry
Spatiotemporal Evolution of the 2022 March Interplanetary Coronal Mass Ejection Revealed by Multipoint Observations of Forbush Decreases. Interplanetary coronal mass ejections (ICMEs) cause "Forbush decreases" (FDs), which are local decreases in background galactic cosmic rays (GCRs). Even though FDs can be observed with simple particle instruments, their amplitude and shape provide physical profiles of passing ICMEs. However, in some cases, previous statistical studies of the heliocentric distance dependence of FD changes associated with ICME propagation have found no strong correlation. We need the criteria for evaluating the relationship between ICME structure and FDs, necessary for the FD's statistical analysis. This study investigates the effect of the evolution and interactions of ICMEs on FD profiles in the inner solar system using multipoint comparisons. We focus on multipoint ICME observations by Solar Orbiter, BepiColombo, and near-Earth spacecraft from 2022 March 10 to 16, when these spacecraft were ideally located for studying the radial and longitudinal evolution of ICMEs and accompanying FDs. We compared GCR variations with the multiple in situ data and ICME model, clarifying the correspondence between the evolution of each ICME structure in the radial and azimuthal directions and the depth and gradients of the FD. The radial comparison revealed decreases in FD intensities and gradients associated with the expansion of the ICME. The longitudinal difference found in FD intensity indicates longitudinal variations of the ICME's shielding effect. These results suggest that accurate multipoint FD comparisons require determining the relationship between the observer's position and the inner structure of the passing ICMEs.

Keywords: Heliosphere, Cosmic ray detectors, Solar wind, Forbush effect, Space weather, Galactic cosmic rays, Solar coronal mass ejections
An Anomalous Symmetric Flare Observed in the Single-lined Spectroscopic Binary TIC 380907942: Assessing Self-lensing and Alternative Hypotheses. We report the observation of an anomalous flare in the Transiting Exoplanet Survey Satellite light curve of TIC 380907942 (HD 10443), a known single-lined spectroscopic binary. Archived spectra suggest this binary contains a G0IV star and an unresolved companion with an orbital period of ∼11 yr. We investigate a variety of hypotheses for the observed light-curve feature, including the possibility that TIC 380907942 is a self-lensing binary in which a compact object gravitationally lenses its stellar companion. We rule out the typical sources of self-lensing false positives, perform a joint fit to the system's light curve and radial velocity data, and discuss future observations needed to confirm the viability of the self-lensing hypothesis. We evaluate the few alternative theories that cannot be excluded at present, including line-of-sight coincidences such as background dwarf novae or active galactic nucleus, and estimate their relative likelihood. If truly a self-lensing binary, TIC 380907942 would possess, by far, the longest orbital period yet observed for such a system.

Keywords: Gravitational microlensing, White dwarf stars, Compact binary stars
Robust Extraction of Global 21 cm Spectrum from Experiments with a Chromatic Beam Based on Physics-motivated Error Modeling. The extraction of the sky-averaged 21 cm signal from Cosmic Dawn and the Epoch of Reionization faces significant challenges. The bright and anisotropic Galactic foreground, which is 4─5 orders of magnitude brighter than the 21 cm signal, when convolved with the inevitably chromatic beam, introduces additional spectral structures that can easily mimic the real 21 cm signal. In this paper, we investigate the signal extraction for a lunar-orbit experiment, where the antenna moves fast in orbit and data from multiple orbits have to be used. We propose a physics-motivated and correlated modeling of both the foreground and the measurement errors. By dividing the sky into multiple regions according to the spectral index distribution and accounting for the full covariance of modeling errors, we jointly fit both the foreground and the 21 cm signal using simulated data for the Discovering the Sky at the Longest wavelength lunar orbit experiment. This method successfully extracts the 21 cm signals of various amplitudes from the simulated data even for a testing antenna with a relatively high level of chromaticity. This approach, which is robust against moderate beam chromaticity, significantly relaxes the stringent design and manufacturing requirements for the antenna, offering a practical solution for future 21 cm global signal experiments either on the ground or in space.

Keywords: Space telescopes, Reionization, Observational cosmology, H I line emission
Preferential Positron Acceleration in Relativistic Magnetized Electron─Positron─Ion Shocks. Relativistic shocks are considered efficient accelerators of charged particles and play crucial roles in high-energy astrophysical phenomena, such as gamma-ray bursts and pulsar winds. This study focuses on positron accelerations in magnetized relativistic shocks in electron─positron─ion plasma. Employing 1D ab initio particle-in-cell simulations, we found a preferential positron acceleration through an interaction with the wakefield associated with a precursor wave in the upstream region. Test particle simulations revealed that the selective acceleration occurs for sufficiently large amplitudes of the wakefield. The mechanism can be understood as the relativistic E × B acceleration formulated in the upstream frame. A theoretical analysis of the positron acceleration in astrophysical contexts is presented, supporting ultrarelativistic shocks in pulsar winds as a primary source for the high-energy positron excess.

Keywords: Cosmic rays, Shocks, High energy astrophysics, Plasma physics
Mass Transfer and Loss in an Extremely Low-mass-ratio Semidetached Binary with a Pulsating A-type Star. AY Gem is a short-period Algol-type eclipsing binary with a period of 3.05 days that is neglected for spectroscopic and photometric investigations. The first radial-velocity curves have been obtained for AY Gem by using LAMOST medium- and low-resolution spectra together with the BFOSC spectral data observed with the 2.16 m telescope in Xinglong station. It is detected that AY Gem is a double-lined spectroscopic binary with an extremely low mass ratio of q = 0.10 ± 0.02. Photometric solutions derived by using the TESS data reveal that it is a semidetached binary, and the absolute parameters were determined to be: M1 = 2.02 ± 0.05 M⊙, M2 = 0.19 ± 0.02 M⊙; R1 = 1.91 ± 0.03 R⊙, R2 = 2.37 ± 0.07 R⊙. By analyzing the O─C diagram, it is found that the orbital period is decreasing continuously, which can be explained as nonconservative mass transfer with a mass-loss rate of  Ṁ∼−10−9M⊙·yr−1 . Meanwhile, it is discovered that AY Gem exhibits a distinct double-peaked Hα emission line, indicating the presence of a transient disk. This is further supported by the measurement of the equivalent width and the q─r diagram. Furthermore, the primary component is identified as a δ Scuti-type star that pulsates at f18 = 11.29511 days−1 and f19 = 11.37374 days−1. These results suggest that AY Gem is a good astrophysical laboratory for investigating mass transfer and loss, binary evolution, and the effect of tidal forces and mass accretion on stellar pulsations.

Keywords: Eclipsing binary stars, Stellar mass loss, Fundamental parameters of stars, Stellar pulsations
On the Optical Emission in the Minioutburst of the Black Hole X-Ray Binary MAXI J1348-630. We investigate the optical emission of the black hole X-ray binary MAXI J1348-630 during its 2019 minioutburst. Using optical data from the Las Cumbres Observatory Global Telescope and X-ray data from Insight-HXMT, we performed time delay analysis, optical-X-ray correlation analysis, and spectral energy distribution (SED) fitting. Our key findings are as follows: (1) The X-ray Comptonization flux lags behind the optical emission by ∼8.5 days, a delay naturally explained by the disk instability model (DIM). (2) The optical and X-ray fluxes show a power-law correlation with a slope ∼0.4, which lies between the predicted values for viscous heating and X-ray reprocessing, consistent with the DIM framework. (3) SED fitting with the irradiated disk model successfully reproduces the quasi-simultaneous optical and X-ray data, and the contribution of the jet is negligible. Our results indicate that the optical emission during the minioutburst originates from the disk, rather than the jet or hot accretion flow, and highlight the critical role of the DIM in understanding the minioutburst of X-ray binaries.

Keywords: Accretion, Low-mass x-ray binary stars, Stellar mass black holes, Optical observation
V570 Per: Characterization of a Benchmark Eclipsing Binary. This study presents a comprehensive analysis of the detached binary system V570 Per through combined photometric, spectroscopic, and astrometric observations. By disentangling the composite spectra, precise fundamental parameters and detailed chemical abundances were determined for both stars. The primary component has a mass of  1.4569−0.0100+0.0094  M⊙, a radius of  1.543−0.009+0.012  R⊙, an effective temperature of  6556−26+64  K, and a metallicity of  +0.18−0.01+0.03  dex, while the secondary has a mass of  1.3579−0.0089+0.0094  M⊙, a radius of  1.377−0.015+0.013  R⊙, an effective temperature of  6468−21+32  K, and a metallicity of  +0.15−0.01+0.02  dex. The system is estimated to be  577−60+60  Myr old with a synchronized orbit. The available O − C data imply a minimum mass of 0.57 M⊙ or 0.11 M⊙ for the third body, corresponding to eccentric and circular orbits, respectively. MESA evolutionary models indicate that the primary will fill its Roche lobe and begin mass transfer to the secondary in about 2.8 Gyr, whereas the secondary will reach the terminal-age main sequence in approximately 3.2 Gyr. The chemical composition of both stars shows remarkable consistency, confirming their common origin, except for calcium, which is significantly enhanced in the primary. Line measurements support this difference and are therefore interpreted as an intrinsic abundance variation rather than an artifact of the analysis. The overall solar-rich metallicity, combined with a relatively low α-element content, links V570 Per to the Galactic thin-disk population. In addition, Galactic orbit analyses of open clusters in the solar neighborhood have revealed that the V570 Per system may have originated from the Melotte 25 open cluster.

Keywords: High resolution spectroscopy, Chemical abundances, Galaxy kinematics, Detached binary stars, Metallicity
Discovery of a Years-delayed Radio Flare from an Unusually Slowly Evolving Tidal Disruption Event Candidate. SDSS J1115+0544 is a unique low-ionization nuclear emission-line region galaxy with energetic ultraviolet (UV), optical, and mid-infrared outbursts occurring in its nucleus. We present the results from an analysis of multiwavelength photometric and radio follow-up observations with a time span of ≍9 yr since its discovery. We find that following a luminosity plateau of ≍500 days, the UV/optical emission has decayed back to the preoutburst level, suggesting that the nuclear outburst might be caused by a stellar tidal disruption event (TDE). In this case, J1115+0544 could be an unusually slowly evolving optical TDE with longest rise and decline time scales ever found. Three years later than the optical peak, a delayed radio brightening was found with a luminosity as high as νLν(5.5 GHz) ∼ 1.9 × 1039 erg s−1. Using a standard equipartition analysis, we find that the outflow powering the radio emission was launched at t ≳ 1150 days with a velocity of v ≲ 0.1c and a minimal kinetic energy of EK ≳ 3 × 1049 erg. The delayed radio brightening coupled with the disappearing plateau in the UV/optical light curves is consistent with the scenario involving delayed ejection of an outflow from a state transition in the disk. SDSS J1115+0544 is the first TDE candidate displaying both a short-lived UV/optical plateau emission and a late-time radio brightening. Future radio observations of these TDEs in the postplateau decay phase will help to establish the connection between outflow launching and changes in accretion rate.

Keywords: Accretion, Tidal disruption, Active galactic nuclei, Radio transient sources
Early Stages of Dusty Tori: The First Infrared Spectra from a Highly Multiscale Quasar Simulation. We present the first infrared (IR) spectral predictions from a self-consistent simulation of the formation of a quasar in a starburst galaxy, spanning the cosmological environment to scales well below the dust sublimation region. The IR emission is dominated by a torus-like dust structure composed of a highly magnetized, turbulence-supported outer accretion disk and of accreting gas tidally torn from the interstellar medium (ISM). At these early stages, the active galactic nucleus is buried and Compton thick. The near- to mid-IR escaping luminosity varies by almost an order of magnitude across sight lines, largely due to extinction from the inflowing stream of cold dust. Self-absorption within the torus suppresses silicate emission features, and further reprocessing by the ambient ISM leads to prominent silicate absorption and colder IR emission. The sublimation structure is stratified by composition and size, producing sight-line-dependent extinction curves that intrinsically vary in shape. However, after repeated scattering in the optically thick dusty medium, these curves emerge substantially grayed. We also demonstrate that bipolar outflows from the central black hole, which carves biconical cavities and reveals the central engine in later stages, can preserve IR anisotropy and silicate features. These results suggest that dusty starburst quasars can undergo a buried, IR-bright phase early in their evolution.

Keywords: Interstellar dust, Starburst galaxies, Quasars, Infrared astronomy, Active galactic nuclei, Radiative transfer
Bayesian Analysis of Wave-optics Gravitationally Lensed Massive Black Hole Binaries with a Space-based Gravitational-wave Detector. Within a Bayesian statistical framework, we jointly estimate the source and lens parameters and evaluate the relative evidence between the lensed and unlensed models. We investigate the wave-optics effects induced by a point-mass lens on gravitational waves (GWs) from massive binary black holes with comparable component masses (q = 0.9) and assess the capability of the space-based GW detector Taiji to detect such effects. Specifically, we investigate the impact of the redshifted lens mass MLz ∈ [3 × 105, 3 × 107] M⊙, the dimensionless impact parameter y is scaled in terms of the Einstein radius of the lens with y ∈ [10, 50], the source redshift zs ∈ [4, 6], and the total source mass Ms ∈ [105, 107] M⊙ on parameter estimation and model selection. Our results indicate that larger MLz values reduce the fitting factor ( FF ), thereby amplifying the waveform residual and its associated residual signal-to-noise ratio ( SNRres ), which enhances the ability to distinguish between lensed and unlensed models. Conversely, for y ≥ 50, the  FF  approaches 1 and  SNRres  becomes too small to allow effective model discrimination. For y ≤ 30, the degeneracy between the luminosity distance dL and MLz can be effectively broken. While the Bayes factor decreases with increasing source redshift zs, lensing signatures remain identifiable up to zs = 6. The influence of the total source mass Ms depends on the overlap of the GW signal with the detector's sensitive band. Overall, effective model discrimination generally requires an  SNRres≥5  (corresponding to  FF≤0.9999994  for the results presented in this work).

Keywords: Bayesian statistics, Gravitational lensing, Gravitational waves
High-contrast L-band Integral Field Spectroscopy of HD 33632 Ab. We present LBTI/ALES 3.07─4.08 μm spectroscopic observations of HD 33632 Ab, a ∼53MJup directly imaged companion to an F8 star. Spectroscopic measurements of HD 33632 Ab now span 1─4 μm, and we perform the first spectroscopic analysis covering this full range. The data are compared to isolated brown dwarf template spectra, indicating that HD 33632 Ab is similar to L8/9 field brown dwarfs. Synthetic atmosphere model spectra from multiple model families are fit, with cloudy models providing the best fits, consistent with expectations for an L dwarf. Evolutionary model predictions for the bulk properties of HD 33632 Ab are highly constrained by the precise dynamical mass found for the object. In particular, predictions for surface gravity are narrowly peaked,  log(g)=5.21±0.05 , and not dependent on the effects of clouds or cloud dispersion. We find significant tension between the surface gravities and object radii inferred from atmosphere model fits and those predicted by evolutionary models. We conclude with a comparison to the spectra of the HR 8799 c, d, and e, and emphasize the case that HD 33632 Ab, and other L/T transition directly imaged companions with constrained masses, will serve an essential role in understanding the complex physical processes governing the appearance of clouds in planetary atmospheres.

Keywords: High contrast techniques, Brown dwarfs, L subdwarfs, Direct imaging, High contrast spectroscopy, Extrasolar gaseous giant planets
Chemical Enrichment of Metal-poor Stars Orbiting Massive Black Hole Companions. There are millions of undetected black holes wandering through our galaxy. Observatories like Chandra, LIGO, and more recently, Gaia, have provided valuable insights into the configurations of these elusive objects when residing in binary systems. Motivated by these advances, we study, for the first time, the enhanced accretion of metals from the interstellar medium (ISM) onto low-mass companions in binary systems with highly unequal mass ratios, utilizing a series of hydrodynamical simulations. Our study demonstrates that a stellar companion's metal accretion history from the ISM alone, from its formation to the present, can significantly influence its surface abundance, especially when enhanced by a massive black hole companion. However, this effect is likely only measurable in stars that are still on the main sequence. Once a stellar companion evolves off the main sequence, similar to what has been observed with the Gaia BH3 companion, the initial dredge-up process is likely to erase any excess surface abundance resulting from the metals that were accreted. As we discover more unequal mass ratio binary systems, it is crucial to understand how the observed metallicity of Sun-like companions may differ from their birth metallicity, especially if they are not yet evolved.

Keywords: Hydrodynamical simulations, Binary stars, Stellar mass black holes, Stellar accretion