Sazuna/UAT_keywords huggingface dataset:
Demonstrating Exoplanet Transit Photometry from Space with a 15 mm Aperture Optical Navigation Camera on Hayabusa2. Observations of exoplanet transits by small satellites have gained increasing attention for reducing biases in the detection of long-period planets. However, no unambiguous detection of an exoplanet has yet been demonstrated using optics with apertures smaller than 60 mm. Here, we investigated the detectability of exoplanet transits using the telescopic Optical Navigation Camera (ONC-T) on board the Hayabusa2 spacecraft, which has an effective aperture of only 15 mm. We conducted transit observations of the hot Jupiters WASP-189 b and MASCARA-1 b, collecting data for 10 and four events, respectively. The transit signal was detected with a signal-to-noise ratio (SNR) of 13 for WASP-189 b and 8 for MASCARA-1 b for each event. Stacking all events improved the SNR to 40 and 16, respectively. The transit midtimes of each event were measured with a precision of 6 minutes and were consistent with Transiting Exoplanet Survey Satellite (TESS) data to within 2 minutes. The planet-to-star radius ratio was determined with an absolute precision of 0.004 (6% relative) and agreed with TESS results to within 0.002 (3% relative). The recent ONC-T and TESS data enabled an update to the planetary ephemerides. We report a 4σ discrepancy between the updated orbital period of MASCARA-1 b and previously reported values. ONC-T sets a new record for the smallest-aperture instrument to detect an exoplanet transit from space, advancing the frontier of exoplanet science with miniature instrumentation. Our results suggest that optics as small as ONC-T may be capable of detecting transiting long-period Jupiters: a population that remains underrepresented in current surveys.

Keywords: Transit instruments, Hot Jupiters, Light curves, Exoplanet detection methods, Transit photometry, Photometer
Search for Faint Lone Double-peaked Hα Lines as Wandering IMBH Signatures in the MUSE Deep Field. Double-peaked Hα emission profiles can serve as potential signatures of accreting intermediate-mass black holes (IMBHs), particularly those residing outside galactic nuclei. Such features are expected to arise from rotating disklike structures around black holes and can be used to identify elusive IMBH candidates. J. Sánchez Almeida et al. reported a sample of such double-peaked Hα sources in the MUSE-Wide survey, interpreting them as potential signatures of wandering IMBHs after systematically excluding alternative explanations. Their method relied on constructing Hα maps around central galaxies and visually identifying compact emission clumps in the surrounding halo regions. In this work, we revisit the analysis using the deeper MUSE Extremely Deep Field (MXDF) data and an automated detection algorithm tailored to identify such features. However, we do not recover any candidate population in MXDF, resulting in a null detection. This outcome is nevertheless informative, as it (1) highlights the inherent challenges in detecting IMBHs and (2) demonstrates the potential of automated approaches for future systematic searches, even though it did not yield a positive outcome in this case.

Keywords: Detection, Intermediate-mass black holes, Galaxy formation, Extragalactic astronomy, Astrophysical black holes
Detection of Four Cold Jupiters through Combined Analyses of Radial Velocity and Astrometry Data. Cold Jupiters play a crucial role in planet formation and dynamical evolution. Since their initial discovery around 47 UMa, they have attracted significant interest; however, their formation mechanisms remain uncertain, underscoring the need to expand the known population. In this work, we combine radial velocity (RV) data with Gaia astrometry using Hipparcos─Gaia proper-motion anomalies over a 25 yr baseline. By jointly modeling both data sets with the Markov Chain Monte Carlo framework, we constrain planetary masses, orbital inclinations, and three-dimensional orbital architectures. This reduces RV degeneracies and improves mass determinations. Four cold Jupiters are reported: HD 68475 b and HD 100508 b are each the first confirmed planet in their systems, with orbital periods  7832−323+463  days and 5681 ± 42 days and dynamical masses of  5.16−0.47+0.53  MJup and  1.2−0.18+0.30  MJup, respectively. In multiplanet systems, HD 48265 c has a period of  10,418−1400+2400  days and a mass of  3.71−0.43+0.68  MJup, while HD 114386 c orbits at  444.00−0.88+0.93  days with a minimum mass of  0.37−0.03+0.03  MJup. The two planets in the HD 48265 system may exhibit a significant mutual inclination, making it a target for testing the von Zeipel─Kozai─Lidov mechanism. HD 68475 b is a promising candidate for future direct imaging with the Extremely Large Telescope's Mid-infrared ELT Imager and Spectrograph. We identified a Jupiter analog with the longest known orbital period among planets with masses between 0.5 and 2 MJup, implying that a substantial population of cold Jupiters likely awaits discovery by Gaia. This study expands the sample of cold Jupiters with constrained orbits and dynamical masses, demonstrating the value of combining RV and astrometry in exoplanet research. *This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: Exoplanet systems, Astrometry, Planetary dynamics, Radial velocity, Extrasolar gaseous giant planets
2MASS Reprocessing. I. The Search for Faint Objects. We present an automated, DAOFind-based pipeline developed to reprocess J-band Atlas All Sky Release Survey images from the Two Micron All Sky Survey (2MASS). By optimizing the detection parameters and implementing a screening procedure that jointly evaluates the signal-to-noise ratio and central sharpness, the pipeline effectively identifies faint point sources that were previously undetected. Applying this method to eight representative sky regions improves the 2MASS detection limit from 16.20 to 16.60 mag and increases the number of detected point sources by approximately 21.36% relative to the 2MASS Point Source Catalog, with a false-positive rate of only 4.80%. These results demonstrate that the proposed reprocessing pipeline can substantially enhance the scientific yield of archival 2MASS data, providing valuable faint-source supplements for studies of time─domain variability, Galactic structure, and cold, low-luminosity objects.

Keywords: Detection, Astronomy data analysis, Infrared sources
Discovery of Seven Cold and Distant Brown Dwarfs with JWST RUBIES. We report near-infrared spectral model fits to seven distant L- and T-type dwarfs observed with the JWST Near Infrared Spectrograph as part of the Red Unknowns: Bright Infrared Extragalactic Survey (RUBIES). Comparison of 0.9─2.5 μm near-infrared spectra of these sources to spectral standards indicates spectral types spanning L1 to T8 and spectrophotometric distances spanning 800─3000 pc. Fits to three grids of spectral models yield atmosphere parameters and spectrophotometric distances largely consistent with our classifications, although fits to L dwarf spectra indicate missing components to the models. Three of our sources have vertical displacements from the Galactic plane exceeding 1 kpc, and have high probabilities of membership in the Galactic thick disk population. Of these, the L dwarf RUBIES-BD-3 (RUBIES-EGS-3081) is well matched to subdwarf standards, while the early T dwarf RUBIES-BD-5 (RUBIES-UDS-170428) is best fit by metal-poor atmosphere models; both may be thick disk or halo brown dwarfs. We critically examine the 1─5 μm spectra of the current sample of 1─2 kpc mid- and late-T dwarfs, finding that temperature, surface gravity, metallicity, and vertical mixing efficiency can all contribute to the observed variations in near-infrared spectral structure and the strength of the 4.2 μm CO2 band. This work aims to guide ongoing JWST, Euclid, and other space-based spectral surveys that are expected to uncover thousands of low-temperature stars and brown dwarfs throughout the Milky Way.

Keywords: Brown dwarfs, Sky surveys, L dwarfs, Milky Way disk, Milky Way stellar halo, T dwarfs
Antarctic Infrared Binocular Telescope: Early Data Release of Observations in the 1.4 μm Water-vapor-absorption Band. Ground-based observations around 1.4 μm are normally limited by strong absorption of telluric water-vapor. However, Dome A, Antarctica has exceptionally dry conditions that offer a unique opportunity for observations in this band. We designed a new filter covering 1.34─1.48 μm, namely  W' , and installed it on the Antarctic Infrared Binocular Telescope (AIRBT) at Dome A in 2025. AIRBT comprises two identical 15 cm optical tube assemblies and two InGaAs cameras equipped with J and  W'  filters, respectively. With this Early Data Release (EDR), we aim to evaluate the performance of the  W'  band at Dome A to observe objects with water-vapor features. This EDR covers ∼20 deg2 in the Galactic plane using ∼20,000 images in three nights. For 2 s exposures, the 5 σ limiting magnitude histogram peaks at J ∼ 11.5 mag (Vega) and  W'∼9.9  mag, respectively. The  J−W'  versus J − H color─color diagram distinguishes ultracool candidates with water-vapor-absorption features from reddened early type stars. Furthermore, later-type stars tend to exhibit stronger water-vapor absorption. Some sources show larger  ∆W'  than ∆J across the three nights, which we attribute to variations of their water-vapor-absorption depth. We conclude that it will be efficient to search for ultracool stars and estimate their spectral subtypes using  W' band imaging at Dome A, where the atmospheric transmission is high and stable.

Keywords: Stellar atmospheres, Photometry, Catalogs, Near infrared astronomy
Stellar and Orbital Characterization of Three Low Mass M Dwarf Binary Stars with Dynamical Spectroscopy from the Habitable Zone Planet Finder. Theoretical models of low-mass stars continue to be discrepant with observations when used to examine the mass─radius relationship and other physical parameters of individual stars. High-resolution spectroscopy that leads to dynamical measurements of binary stars can directly improve these models. We have been using the Habitable-Zone Planet Finder spectrograph to monitor binary stars with M dwarf components. Here, we measure the orbital and stellar parameters for three such systems: LSPM J0515+5911, NLTT 43564, and NLTT 45468. Each system has dozens of spectra obtained over a baseline of several years. None of the systems appear to be eclipsing, so our ability to turn them into true benchmark binaries with purely dynamical measurements is limited. We use literature photometry to estimate each system's spectral energy distribution and utilize models in combination with detection limits of our spectroscopic measurements to probe characteristics of the companions. LSPM J0515+5911 is a double-lined spectroscopic binary with a period of 126.948 ± 0.029 days and derived minimum masses,  M1sin3i=0.058±0.002  M⊙ and  M2sin3i=0.046±0.001  M⊙for the primary and secondary components, respectively. We solved NLTT 43564 with a period of 1877 ± 24 days and NLTT 45468 with a period of 9.686 ± 0.001 days as single lined systems and modeled the primary masses to be M1 = 0.32 ± 0.02 M⊙ and  M1=0.35−0.07+0.02  M⊙, respectively. *Based on observations obtained with the Hobby─Eberly Telescope (HET), which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximillians-Universitaet Muenchen, and Georg─August Universitaet Goettingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly.

Keywords: Low mass stars, Binary stars, Companion stars
HET/HPF Observations of Helium in Warm, Hot, and Ultrahot Jupiters. The near-infrared helium triplet line is a powerful tool for studying atmospheric escape processes of close-in exoplanets, especially irradiated gas giants. Line profile fitting provides direct insight into the mechanisms driving atmospheric mass loss of close-in, Jupiter-sized planets. We present high-resolution transmission spectroscopy results for the helium triplet line of 16 gas giants (Rp &gt; 0.5RJup). These observations are part of an extensive helium survey conducted using the Habitable Zone Planet Finder spectrograph on the 10 m Hobby-Eberly Telescope. For the first time, we provide constraints on the helium line for HAT-P-12 b, HAT-P-17 b, HD 118203 b, TrES-1 b, and WASP-156 b. Additionally, we are able to confirm previous robust or tentative detections for HD 189733 b, HD 209458 b, WASP-52 b, WASP-69 b, and WASP-76 b, and nondetections for HAT-P-3 b, WASP-11 b, WASP-80 b, WASP-127 b, and WASP-177 b. We do not confirm the previous helium narrow-band detection in HAT-P-26 b using high-resolution observations. To identify trends within the population of warm, hot, and ultrahot Jupiters, we combined our results with available helium studies from the literature. As predicted by theory, we find that warm Jupiters with helium detections orbit K-type stars. However, the helium detections at equilibrium temperatures of ∼2000 K are found in low-density planets orbiting F-type stars. We compiled a list of 46 irradiated gas giants, but more helium studies are needed to increase the sample and improve our understanding of atmospheric mass loss through helium observations.

Keywords: High resolution spectroscopy, Exoplanet atmospheres, Exoplanet atmospheric variability, Exoplanets
Mapping the Cloud-driven Atmospheric Dynamics and Chemistry of an Isolated Exoplanet Analog with Harmonic Signatures. Young planetary-mass objects and brown dwarfs near the L─T spectral transition exhibit enhanced spectrophotometric variability over field brown dwarfs. Patchy clouds, auroral processes, stratospheric hot spots, and complex carbon chemistry have all been proposed as potential sources of this variability. Using time-resolved, low- to mid-resolution spectroscopy collected with the JWST/NIRISS and NIRSpec instruments, we apply harmonic analysis to SIMP J013656.5+093347.3, a highly variable, young, isolated planetary-mass object. Odd harmonics (k = 3) at pressure levels (≳1 bar) corresponding to iron (Fe) and forsterite (Mg2SiO4) cloud formation suggest a potential north─south hemispheric asymmetry in the cloudy, and likely equatorial, regions. We use the inferred harmonics, along with 1D substellar atmospheric models, to map the flux variability by atmospheric pressure level. These vertical maps demonstrate robust interaction between deep convective weather layers and the overlying stratified and radiative atmosphere. We identify distinct time-varying structures in the near-infrared that we interpret as planetary-scale wave-associated (e.g., Rossby or Kelvin) cloud modulation. We detect deviations from bulk (composite) variability in water (maximum signal-to-noise ratio (S/Nmax)=14.0 ), carbon monoxide ( S/Nmax=13.0 ), and methane ( S/Nmax=14.9 ) molecular signatures. Forsterite cloud modulation is anticorrelated with the overlying carbon monoxide and water abundances and correlated with deep methane absorption, suggesting complex interaction between cloud formation, atmospheric chemistry, and temperature structure. Furthermore, we identify distinct harmonic behavior between methane and carbon monoxide absorption bands, providing evidence for time-resolved disequilibrium carbon chemistry. At the lowest pressures (≲100 mbar), we find that the mapped methane lines transition from absorption to emission, supporting evidence of high-altitude auroral heating via electron precipitation.

Keywords: Brown dwarfs, Exoplanet atmospheric dynamics, Exoplanet atmospheric variability, Extrasolar gaseous giant planets, Exoplanet atmospheres, T dwarfs
A Galactic Supernova Remnant Candidate at l = 25<inline-formula> <mml:math><mml:mover><mml:mrow><mml:mi>.</mml:mi></mml:mrow><mml:mrow><mml:mi>°</mml:mi></mml:mrow></mml:mover></mml:math> </inline-formula>8, b = +0<inline-formula> <mml:math><mml:mover><mml:mrow><mml:mi>.</mml:mi></mml:mrow><mml:mrow><mml:mi>°</mml:mi></mml:mrow></mml:mover></mml:math> </inline-formula>2 Revealed by Near-infrared Imaging and Spectroscopy. We present high-resolution near-infrared spectroscopic observations of the newly identified supernova remnant candidate G25.8+0.2 obtained with the Immersion Grating Infrared Spectrograph on the Harlan J. Smith Telescope. The source was originally discovered in the UKIRT Wide-field Infrared Survey for Fe+. Our spectra reveal multiple kinematic components in [Fe II] 1.644 μm emission. The high-velocity components exhibit elevated [Fe II]/Brγ ratios characteristic of shock excitation, while the low-velocity components are dominated by hydrogen and helium recombination lines and are consistent with photoionized gas, indicating an H II-region origin. G25.8+0.2 lies within the G26 complex, a large ( ∼15'×30' , corresponding to ∼28 pc × 57 pc at a distance of 6.5 kpc) star-forming region in the inner Galaxy. The shock-excited [Fe II] filaments closely trace the morphology of the bright radio shell that partially encloses centrally filled soft X-ray emission, strongly suggesting recent supernova activity in this region. We discuss the physical nature of G25.8+0.2 and its relationship to the surrounding G26 star-forming complex. In addition, we derive the extinction toward the source using Brackett line ratios and constrain the spectral types of the dominant ionizing stars from the He I 2.058 μm/Brγ line ratios.

Keywords: Supernova remnants, Shocks, Emission nebulae, Infrared spectroscopy
First Astrometric Limits on Binary Planets and Exomoons Orbiting β Pictoris b. The search for exomoons, or moons in other star systems, has attracted significant interest in recent years, driven both by advancements in detection sensitivity and by the expanding population of known exoplanets. The β Pictoris system is a particularly favorable target, as its proximity and directly imaged planets allow for precise astrometric monitoring. We present astrometric constraints on the presence of binary planets and exomoons in the β Pictoris system using archival observations from the GRAVITY interferometer and SPHERE instruments. We calculate these limits by modeling the motion of the two orbiting planets and introducing an additional perturbation to the model that simulates the astrometric motion caused by an exomoon orbiting the planet β Pictoris b. We find that for short orbital periods (≍50 days), a lunar companion is only allowed if its mass remains below ≍180 M⊕ (0.6 MJup) at 3σ confidence. At intermediate periods near 300 days, we exclude moons more massive than ≍65 M⊕ (0.2 MJup) at 3σ confidence. At longer orbital periods, we place the tightest constraints, ruling out any potential exomoon above ≍50 M⊕ (0.15 MJup) at 700 days and ≍30 M⊕ (0.1 MJup) at 1100 days (both at 3σ confidence). These results place the first astrometric constraints on moons and binary planets in the β Pictoris system and demonstrate the sensitivity of interferometric observations for exomoon studies.

Keywords: Optical interferometry, Natural satellites (Extrasolar), Astrometric exoplanet detection, Direct imaging, Astrometry
Uniform Forward-modeling Analysis of Ultracool Dwarfs. IV. Benchmarking the Sonora Diamondback and D. Saumon &amp; M. S. Marley () Atmospheric Models Across Late M, L, and T Types with Low-resolution 0.8─2.5 μm Spectroscopy. We present a systematic assessment of two major cloudy atmospheric model grids—SM08 and Sonora Diamondback—when applied to low-resolution, near-infrared (0.8─2.5 μm) spectroscopy. Our analysis focuses on a uniform sample of 142 age-benchmark brown dwarfs and planetary-mass objects spanning late M, L, and T spectral types, with independently determined ages from 10 Myr to 10 Gyr. We perform forward-model spectral fitting for all benchmarks' Infrared Telescope Facility/SpeX spectra (R ∼ 80─250) using both SM08 and Sonora Diamondback atmospheric models to infer effective temperatures, surface gravities, metallicities, radii, and cloud sedimentation efficiencies. The two model grids yield broadly consistent results. Among L4─L9 dwarfs, we identify a statistically significant, population-level age dependence of the cloud parameter fsed, with young benchmarks (&lt;300 Myr) exhibiting systematically lower fsed values than older counterparts. This trend is absent across L0─T5 and T0─T5, demonstrating that cloud properties vary with age and surface gravity and offering explanations for the observed gravity-dependent photometric properties at the late L end of the L/T transition. By comparing spectroscopically inferred parameters with predictions from evolution models, we quantify systematic errors in the fitted atmospheric parameters and establish empirical calibrations to anchor future studies using these models. Stacked residuals across the sample reveal wavelength-dependent data─model mismatches associated with key atomic and molecular absorption bands, highlighting the need for improved opacities and rainout chemistry. In particular, persistent residuals in FeH bands likely contribute to the difficulty of robustly constraining  log(g)  and mass from spectral fitting for late M and L dwarfs. Finally, we show that including an interstellar-medium-like extinction term significantly improves the spectral fits, confirming and broadening previous findings and suggesting missing opacity sources in current cloudy models.

Keywords: Brown dwarfs, Infrared spectroscopy, Atmospheric clouds, L dwarfs, Stellar atmospheres, T dwarfs
High-resolution Observations of CO(3─2) in Haro 2: Cool Molecular Outflows of a Lyα Emitter. Haro 2 is a blue compact dwarf galaxy and the closest (at 21 Mpc) known Lyα emitter. UV and optical observations have found Haro 2 to be immersed in shells of partly ionized gas expanding at ∼200 km s−1. Observations of CO(2─1) with moderate (2″) resolution discovered a large-scale one-sided outflow associated with a soft X-ray bubble and apparently driven by the young star clusters created in the recent starburst. We present here Submillimeter Array observations of CO(3─2) with 1 .″ 1 resolution in Haro 2. The opposite-side component of the large molecular outflow is detected lying in the direction of the fast ionized outflow; it is very confined in area. An additional outflow is apparent in the CO(3─2); it is southeast of the galaxy in a region holding weak star formation and a moderate-luminosity hard X-ray source. All the molecular outflow and filament velocities are within ≲±50 km s−1 of the systemic velocity of the galaxy.

Keywords: Lyman-alpha galaxies, Galactic winds, Blue compact dwarf galaxies, Star clusters
Kinematics of H I Envelopes Associated with Molecular Clouds. We investigate the evolution of molecular clouds through the kinematics of their atomic hydrogen (H I) envelopes, using 12CO and 21 cm emission to trace the molecular and atomic gas, respectively. We measure the large-scale gradients, Ω, in the velocity fields of 22 molecular clouds and their H I envelopes, then calculate their specific angular momenta, j ∝ ΩR2. The molecular clouds have a median velocity gradient of 9.6 × 10−2 km s−1 pc−1, and a typical specific angular momentum of 2.7 × 1024 cm2 s−1. The H I envelopes have smaller velocity gradients than their respective molecular clouds, with an average of ΩH I = 0.03 km s−1 pc−1, and a median angular momentum of of jH I ≍ 5.7 × 1024 cm2 s−1. For a majority of the systems,  jHI&gt;jH2 , with an average of  jHI/jH2=4 . Their velocity gradient directions tend to be misaligned, indicating that angular momentum is not conserved during molecular cloud formation. Both populations exhibit a j − R scaling consistent with that expected of supersonic turbulence:  jH2∝R1.67±0.22 , and jH I ∝ R1.71±0.27. Combining our measurements with previous observations, we demonstrate a scaling of j ∝ R1.50±0.02 in star-forming regions spanning 5 dex in size, R ∈ (10−3, 102) pc. We construct a model of angular momentum transport during molecular cloud formation, and derive the angular momenta of the progenitors to the present-day systems. We calculate a typical angular momentum redistribution timescale of 13 Myr, comparable to the H I envelope free-fall times.

Keywords: Molecular clouds, Interstellar medium, Dense interstellar clouds