Sazuna/UAT_keywords huggingface dataset:
First Separation of Iron Lines in the Cataclysmic Variable IGR J14536-5522 with Suzaku/XIS. We present new analysis of the cataclysmic variable IGR J14536-5522 observed with the X-ray Imaging Spectrometer onboard the Suzaku satellite. Based on the light curve, we did not confirm the periodicity (3756 s) reported in the literature. Instead, its power spectrum shows a marginal peak near ∼1000 s with a continuously decreasing 1/f-like component. Additionally, we newly resolved three Iron emission lines (6.4, 6.7, and 7.0 keV), and constrained the physical parameters. However, the model fails to reasonably explain the unexpectedly finer line width of the Fe XXV Heα 6.7 keV. This feature is likely caused by a malfunction in the detectors or calibration, or statistical fluctuation.

Keywords: X-ray astronomy, Cataclysmic variable stars, X-ray point sources, X-ray binary stars
Spatially Resolved Analysis of Ionization Mechanisms in SGAS1723+34. Understanding the ionizing sources inside galaxies has been a decades-long goal for astronomers. Using spatially resolved JWST/NIRSpec data, we explore the emission line diagnostics [O III]/Hβ versus [N II]/Hα and [S II]/Hα in SGAS1723+34, a galaxy at redshift z = 1.3293. The diagnostic diagrams show possible Active Galactic Nucleus (AGN) ionization in the galaxy; however, with further analysis of the imaging contours, we find that this AGN detection is located within a star-forming clump. We propose that the AGN detection from the BPT diagram is caused by the galaxy-wide formation of stellar populations with harder ionizing spectra than those found at low redshift.

Keywords: Gravitational lensing, Galaxy evolution, Ionization
A Long Tidal Feature Extending from a Low-redshift Galaxy Revealed in Rubin Data Preview 1 Imaging. Using the Vera C. Rubin Observatory Data Preview 1, we present the detection and photometric analysis of a stellar stream extending along the minor axis of a massive disk-galaxy, LEDA 751050, at a redshift of z = 0.1 in the Extended Chandra Deep Field-South. This feature appears to be an analog of the M31 Giant Stellar Stream, spanning around 130 kpc by 15 kpc, with an estimated stellar mass of M ⋆ = 6 × 108 M ⊙, and a mean g-band surface brightness (SB) of μ  g  = 28.6 mag arcsec−2. This discovery demonstrates Rubin's ability to reveal low-SB substructures and foreshadows the future capabilities when the full Legacy Survey of Space and Time dataset is actualized.

Keywords: Stellar streams, Tidal disruption, Galaxy interactions, Dwarf galaxies, Galaxy tides, Low surface brightness galaxies
A Précis of the MOA-II Observations. The Microlensing Observations in Astrophysics (MOA) collaboration is an international research project that uses gravitational microlensing for the discovery of exoplanets. MOA was initiated in the late 1990s and primarily involves institutions from Japan and New Zealand. The collaboration's observation site is the Mount John Observatory in New Zealand. We present here an overview of the MOA collaboration data archive, in terms of the monthly and annual number of images taken towards the MOA fields in the Galactic bulge and Magellanic Cloud regions, exposure times, the time between observations, and the monthly altitude distribution of observations (Reasonable requests for MOA data will be considered by the MOA collaboration. Primary contacts for data requests are Preeti Cowan (preeti.cowan@auckland.ac.nz) and Nicholas Rattenbury (n.rattenbury@auckland.ac.nz)).

Keywords: Surveys
Discovery of Microsecond Duration Radio Flashes with Small Radio Telescopes. We present the discovery of floods of short duration transient radio events detected simultaneously by at least 3 of 7 small horn radio telescopes, when continuously observing the sky at 1421.5 ± 3.0 MHz. The goal of these observations is to detect transient radio flashes, which are expected when high-energy cosmic rays hit Earth's atmosphere. We find a variety of radio flash patterns, including expected isolated radio flashes, a grouping of a few events, primarily seen near Sun transit, and floods of events, where thousands of flashes are seen over periods of hours. The origin of these flood events have not yet been determined, but are likely due to a variety of causes, including solar events, bursts of cosmic rays, human interference, weather, and (perhaps) communication from extraterrestrial sources. High school students and teachers are encouraged to participate in the building of electronics and telescopes for radio observations.

Keywords: Technosignatures, Radio astronomy, High energy astrophysics
Modeling of Circumstellar Alumina and Silicate Dust around Evolved Stars. Spectra of some asymptotic giant branch (AGB) and red supergiant (RSG) stars show emission features at mid-infrared wavelengths, such as at 13 μm, that have previously been inconclusively identified. We present models of dust emission seen in spectra of 3 oxygen-rich (O-rich) AGB stars and 1 RSG star. The models utilize the opacities of grains of amorphous silicates, amorphous alumina, corundum, and other polymorphs of alumina to fit the dust spectra. Corundum fits the 13 μm feature, and other polymorphs of alumina plus amorphous alumina are required to fit the other characteristics of the spectra.

Keywords: Asymptotic giant branch stars, Circumstellar dust, Evolved stars
Automatic Dust Detection, Isolation, and Mass Measurement Pipeline. Dust in elliptical galaxy cores provides insights into the interstellar medium and galactic evolution. I present an automated pipeline analyzing archived Hubble Space Telescope WFPC2 and ACS images to detect and measure dust masses in early-type galaxies. Using iterative unsharp masking with Gaussian smoothing to reconstruct dust-free galaxy models, I derive dust surface densities and estimate total masses from extinction maps using a thin-screen approximation and dust mass absorption coefficient κλ = 0.77. This automated method enables consistent application to large samples, providing a framework for future large-scale studies.

Keywords: Interstellar dust, Interstellar dust extinction
Monsters in the Dark: Revealing Hidden Bars in Submillimeter Galaxies. Using JWST NIRCam F444W imaging from the SCUBADive project, we identify five sub-millimeter galaxies that host stellar bars. These include AzTECC91_0 at z = 1.91 ± 0.11, which has the most extended bar known at z &gt; 1 (8.42 ± 0.05 kpc), and AzTECC27_1 at z = 3.45 ± 1.30, one of the highest-redshift unlensed bar candidates.

Keywords: Submillimeter astronomy, James Webb Space Telescope, Barred spiral galaxies
Ionization Stratification and Stellar Feedback in the Galactic H II Region Sh2-124 from Deep Narrowband Imaging. I present deep narrowband imaging of the Galactic H II region Sh2-124 obtained with a total integration time of 79 hr using 2.5 nm S II, Hα, and O III filters. The observations reveal a well-defined shell morphology with clear ionization stratification, dense compression fronts, and photo-eroded dust structures. Comparison with known stellar content and molecular gas distributions suggests that Sh2-124 is shaped by ongoing stellar feedback operating within a non-uniform interstellar medium. The data also reveal faint extended emission beyond the bright shell, indicating partial leakage of ionizing radiation not readily apparent in existing survey data.

Keywords: H II regions, Interstellar medium, Astrophotography
The Size of 3I/ATLAS from Non-gravitational Acceleration. The third macroscopic interstellar object detected in the solar system recently passed through perihelion, with the best-fitting models of its trajectory now featuring non-gravitational accelerations (NGAs). We assess how much mass loss is required to produce plausible NGA solutions and compare with estimates of the mass loss. We find that they are consistent when the nucleus of 3I/ATLAS is around 1 km in diameter. For a recent solution with a time lag in the acceleration from Eubanks et al., we find diameters between 820 and 1050 m, assuming an outgassing asymmetry factor ζ = 0.5 and a density of the comet nucleus ρ = 0.5 g cm−3. The limits on the diameter scale as (ζ/ρ)1/3. Substantial extrapolation is required in general to compare NGAs to mass loss rates, so reliable estimates of the mass loss rate at other stages of the comet's trajectory will substantially reduce the systematic uncertainty in this estimate.

Keywords: Comets, Interstellar objects
A Terrestrial-sized Planet Candidate Orbiting the Nearby M-dwarf TIC 22760643.01. The identification and multi-sector validation of a terrestrial-sized planet candidate orbiting the nearby M-dwarf TIC 22760643 (L 326-21, d ≍ 15.8 pc) are reported. Using TESS photometry from Sectors 10, 37, and 64, a periodic transit signal with an average orbital period of P ≍ 7.58 days is characterized. The analysis reveals a stable transit depth of approximately 1100 ppm across three years of observations. Utilizing stellar parameters (R* = 0.27R⊙, Teff = 3219 K), a planetary radius ranging from 0.95 to 1.07R⊕ is derived. False-positive mitigation, including centroid offset analysis (0.003 pixels) and a secondary eclipse search, strongly supports the planetary nature of the signal. Given its proximity, this candidate is a high-priority target for future mass measurement and atmospheric characterization.

Keywords: Exoplanet astronomy, Transit photometry, Light curves, Exoplanets
A Simple One-free-parameter Model of the Solar Chromosphere Explains Solar Chromospheric Line Variations Measured by NEID at WIYN during the 2023 October Solar Eclipse. We have modeled Hα equivalent width and Ca II H &amp; K S index measurements of disk-integrated sunlight during the 2023 October solar eclipse as measured by NEID using a one-free-parameter analytic model of the Sun, where the line is in absorption in the solar disk and in emission on the limb. We find the model to be in reasonable qualitative agreement with our data, and to explain the apparent strengthening of the absorption lines at beginning and end of eclipse. We suggest such a model might have utility in analyses of chromospheric lines in eclipsing binaries.

Keywords: High resolution spectroscopy, Eclipses, Solar chromosphere
First Tabulation of the Sunspot-cycle Start in the Seventeen Cycles Since the Cycle's Discovery: Consequences for the Solar Dynamo?. In the seventeen Cycles 8─24 the first new-cycle sunspot group is tabulated for the first time in each solar hemisphere (thirty-four groups). This allows the determination of the central-value of two parameters of the sunspot-cycle start, as a hemispheric average, since the cycle's discovery two hundred years ago: first emergence epoch and latitude. The tabulation uses the state-of-the-art cycle-separation data obtained by R. Leussu et al. As a median over the seventeen cycles, the first group is found to have emerged 1.4 yr before sunspot minimum. Its median unsigned latitude is 27  $\mathop{.}\limits^{^\circ }$  &lt;?MML   . °  ?&gt; 15, lower than in an earlier estimate by A. P. Kramynin &amp; F. A. Mikhalina based on only thirteen groups. This initial median latitude is similar to the ≍27  $\mathop{.}\limits^{^\circ }$  &lt;?MML   . °  ?&gt; 0 group latitude found by other authors at sunspot minimum epoch. If reproduced, this finding could result in a new observational constraint on solar-dynamo models.

Keywords: Solar cycle, Sunspot groups, Sunspot number, Sunspots, Solar dynamo, Sunspot cycle
Gravity-darkening Coefficients for the Space Mission JWST, Based on PHOENIX Spherical Models at High Resolution: NIRCam, NIRISS, and NIRSpec Passbands. Space-based photometry has revealed the subtle effects of gravity darkening on the light curves of transiting exoplanets, allowing valuable new information on these objects to be retrieved. For some applications, these effects are parametrized in terms of the wavelength-dependent gravity-darkening (GD) coefficients, y(λ). To facilitate such studies, here we present theoretical calculations based on high-resolution PHOENIX models, providing GD coefficients for 11 passbands used with three different instruments onboard JWST.

Keywords: James Webb Space Telescope, Stellar atmospheres, Exoplanet tides, Exoplanet detection methods, Stellar rotation, Gravity darkening
Rare Near-opposition Alignment of 3I/ATLAS on 2026 January 22. We point out that on 2026 January 22, the interstellar object 3I/ATLAS will align to within an exceptionally small angle,  α=0.°69 , with the Earth─Sun axis. This rare alignment provides unique circumstances for measuring the opposition surge and polarimetric properties of interstellar cometary dust. We characterize the alignment geometry, outline key scientific opportunities, and define the observational requirements for data collection. Observations before and after the alignment time offer an unprecedented opportunity which may not repeat for decades, for characterizing the albedo, structure, and composition of interstellar matter.

Keywords: Interstellar dust, Comets
Hidden Companions to Intermediate-mass Stars. XXXIV. Discovery of the Companions in Five "Boring" Accelerating A-type Stars. Better constraints on the multiplicity properties of A-type stars are relevant to understand the formation of intermediate-mass multiple systems as well as to constrain the multiplicity properties of their descendant white dwarfs. Here we report on the discovery of the companions to five nearby, accelerating and relatively bright (V ∼ 6) but otherwise unremarkable A-type stars based on VLTI/GRAVITY near-infrared interferometric observations. The companions have masses 0.53─1.47 M⊙ and projected separations 16─200 mas (1─13 au). One of the systems will become a wide (several astronomical unit) double white dwarf binary within less than a Hubble time. *Based on observations collected at the European Southern Observatory, Chile, Program IDs 111.24UP.001, 113.26GM.001, 114.27DS.001.

Keywords: Optical interferometry, Multiple stars, A stars
Effect of Different Non-gravitational Accelerations on the Trajectory of Interstellar Comet 3I/ATLAS. Comet C/2025 N1 or 3I/ATLAS is the third confirmed interstellar object. It has passed perihelion on 2025 October 29, and is currently on a path to leave the solar system. During its outbound journey, it will pass close to Jupiter at a distance of 0.358 au. NASA JPL HORIZONS has updated the non-gravitational parameters of the comet based on the CO2 sublimation model, where g(r) = 1/r2. In this research note, we use the non-gravitational accelerations from HORIZONS together with symmetric and asymmetric H2O sublimation models derived using Find_Orb software. We calculate the resulting perijove distances and compare them with our earlier results at epoch JD 2460867.5.

Keywords: Comets, Comet dynamics, Interstellar objects, N-body simulations
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. XXVII. HD 1909 (AV Scl). The weak line of Hg II located at 5677.10 Å is used to measure the mercury abundance in the most massive component of the SB 2 HgMn star HD 1909 (AV Scl). This line, which absorbs about 5% of the adjacent continuum, is one of the strongest studied in this series. The synthesis of this line confirms a large overabundance of mercury, about +5.70 dex, which remains lower than the excess derived from the 3983.93 Å line in earlier studies but agrees well with the abundance I published in a recent Note. The synthesis of the 3983.93 Å line yields the same abundance. Both lines may be variable reflecting an inhomogeneous distribution of mercury over the surface of HD 1909.

Keywords: Mercury-manganese stars, Chemically peculiar stars
Morphology and Hydrological Context of the McCauley Crater Delta, Mars. McCauley crater hosts a well-preserved delta in a palaeolake northeast of the Hellas Basin on Mars. Its formation records hydrological activity possibly driven by episodic glacial meltwater input. Morphological analyses of image and topographic data sets reveal a gently sloping delta with inverted channels and superposed boulders, indicative of variable depositional energy and repeated flow events. Hydraulic reconstruction suggests delta accumulation occurred over an active duration of ∼25 kyr, pointing to a stable lacustrine environment capable of sustaining fluvial activity under cold conditions that could have supported habitable environments.

Keywords: Mars
Kinetic Temperature Rate Coefficients for Dissociative Recombination of CH<SUP>+</SUP>. The rate coefficient for dissociative recombination (DR) of CH+ is needed to model clouds in the interstellar medium (ISM). Theoretical data for DR are typically obtained in the form of cross sections as a function of collision energy. However, astrochemical modelers need rate coefficients as a function of the kinetic temperature of the gas, i.e., the cross section averaged over the electron velocity distribution of the plasma. Molecules in the ISM are typically in their lowest energy states. To this end, we have calculated the kinetic temperature rate coefficients for DR of electronically, vibrationally, and rotationally cold CH+ over a temperature range of 1─5000 K, using theoretical cross sections from J. Forer et al. We have also fit our results to two commonly used modeling formulae and present the corresponding fit parameters.

Keywords: Interstellar molecules, Reaction rates, Astrochemistry, Electron recombination reactions, Diffuse molecular clouds
A UV Spectroscopic Analysis of VY Scl during the Deep Low State of 1983. We focus on the archival UV Spectra of VY Scl obtained by the IUE spacecraft during the 1983 deep low state of the system. Calculations and UV modeling of the accretion disk and white dwarf (WD) in VY Scl is presented. We find that the accretion disk dominates the UV flux accounting for 64% of the UV flux. Despite the deep low state, considerable flux from the accretion disk remains and disk light dominates the UV light. In other VY Scl type nova-like, e.g., MV Lyrae and TT Ari, the WD accounts for ∼100% of the UV flux during their low states. Any significant disk truncation due to a magnetic accretor is absent.

Keywords: Nova-like variable stars, Cataclysmic variable stars
Full-depth unWISE Coadds through the End of the NEOWISE Mission. We have combined Wide-field Infrared Survey Explorer (WISE) and NEOWISE science exposures spanning from 2010 January through 2024 July to create the deepest ever full-sky maps at 3.4 μm (W1) and 4.6 μm (W2). These maps, which we publicly release, are based on ∼11.5 yr of WISE and NEOWISE observations in each of these two bands. As our new all-sky set of full-depth unWISE coadds uniformly incorporates observations from the entirety of the WISE and NEOWISE missions, it represents a valuable legacy dataset for Galactic and extragalactic astronomy in the infrared.

Keywords: Infrared astronomy, Astronomy image processing, Astronomy data analysis, Surveys
A High-amplitude Radial Velocity Variable in DESI DR1: Gaia DR3 3802130935635096832. I report a large-amplitude radial velocity (RV) variable, Gaia DR3 3802130935635096832, identified in the Dark Energy Spectroscopic Instrument (DESI) DR1 Milky Way Survey. The DESI catalog RVs span  ∆RVmax≍146  km s−1 over 38.9 days. Gaia DR3 lists a neighbor at angular separation  ρ≃0.″688  (∆G ≃ 2.21 mag), so contamination and background variability are plausible. Using per-exposure DESI cframe spectra, I find that sky-dominated wavelengths in the Z arm can bias the same-night pair; restricting to the Ca II triplet window (8500─9000 Å) yields a trusted swing ∆RV ≍ 151 km s−1. Relative spectrophotometric fluxes in this window are stable to ∼0.13 mag. The source merits resolved follow-up spectroscopy or imaging to distinguish a compact companion from a blended variable.

Keywords: M dwarf stars, Neutron stars, Stellar mass black holes, Spectroscopic binary stars, Compact objects, Spectroscopy, Radial velocity
SPHEREx Reobservation of Interstellar Object 3I/ATLAS in 2025 December: Detection of Increased Post-perihelion Activity, Refractory Coma Dust, and New Coma Gas Species. In 2025 December, SPHEREx re-observed 3I/ATLAS post-perihelion, finding a much more active object compared to 2025 August SPHEREx pre-perihelion observations, with marked evidence for development into an cometary body fully sublimating all its ices. The new imaging spectrophotometry was dominated by spatially resolved features due to light scattered by dust, along with thermal emission, plus gas-line-emissions from CN(∼0.93 μm), H2O(∼2.7 μm), organic C─H(3.2─3.6 μm), CO2(4.25─4.27 μm), and CO(∼4.7 μm). The CO2 gas-coma continued to be extended out to ∼3' radius. The continuum spectral signature of H2O-ice absorption had mostly disappeared, replaced by scattered-light plus thermal-emission from organo-silicaceous dust grains while the H2O gas-emission is 40× higher. The CO- and CO2-gas comae were circularly symmetric, while the other comae appear morphologically similar to the dust-coma with its pear-shaped, solar-pointing, large icy dust grains dust tail. The new appearance of CN and C─H features suggests that these species were contained either in H2O phases or were trapped under them.

Keywords: Interplanetary medium, Small Solar System bodies, Comae, Near infrared astronomy, Neutral coma gases, Interstellar objects, Comets, Spectrophotometry, Coma dust
Optically Thin Models and Radiative Transfer Models of AGB Stars. Asymptotic giant branch (AGB) stars are evolved stars that eject large amounts of dust. Here, we present emission models of circumstellar dust shells around two oxygen-rich AGB stars—RX Boo and HT Aqr—and one S star, Y Lyn. These models suggest that corundum is the most likely cause of the 13 μm feature and that other alumina polymorphs may contribute to the 11, 20, 28, and 32 μm features.

Keywords: Infrared astronomy, Radiative transfer simulations, Circumstellar dust, Asymptotic giant branch stars
TSSC Comet-centered Data Products from TESS 3I/ATLAS Observations. 3I/ATLAS is the third known interstellar object to pass through our solar system. NASA's Transiting Exoplanet Survey Satellite (TESS) made dedicated observations of 3I/ATLAS between 2026 January 15 and 22 (Sector 1751), capturing high-cadence observations at 200 and 20 s cadence. We present two High Level Science Products: (1) comet-centered image time series, corrected for background scattered light and stars; and (2) aperture light curves extracted from the corrected images. We created these data products using the official TESS products and they are publicly available at the Mikulski Archive for Space Telescopes. TESS's high-precision, near-continuous photometry will provide unique insights into the comet's activity following its closest approach to the Sun. The TESS Science Support Center (TSSC) has created these data products to facilitate scientific analyses by the TESS and solar system communities.

Keywords: Time domain astronomy, Comets, Interstellar objects, Photometry
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. XXVIII. HD 19400 (θ Hyi). The weak line of Hg II located at 5677.10 Å is used to measure the mercury abundance in the late B-type star HD 19400 (θ Hyi). This line is detected at 3σ above the noise in the adjacent continuum. The synthesis of this line confirms a large overabundance of mercury, about +5.30 dex, which agrees very well with the excess derived from the other Hg II line at 3983.93 Å. Spectrum synthesis yields estimates of the abundance deficiencies/excesses for 20 other elements. The following excesses/deficiencies are found: helium (−1.30 dex), carbon (−0.40), oxygen (−0.60), neon (0.00), magnesium (0.00), aluminium (−1.30), silicon (+0.48), phosphorus (+2.30), sulfur (−0.82), calcium (0.00), titanium (0.88), chromium (0.67), manganese (1.83), iron (0.85), gallium (3.00), strontium (+0.70), yttrium (0.60), zirconium (0.00), xenon (+5.00) and barium (+0.00). Most light elements are deficient (except for Si and P), the iron-peak elements are all overabundant, gallium and xenon are very overabundant.

Keywords: Mercury-manganese stars, Chemically peculiar stars