Sazuna/UAT_keywords huggingface dataset:
Free-floating Planet Mass Function from MOA-II 9 yr Survey toward the Galactic Bulge. We present the first measurement of the mass function of free-floating planets (FFPs), or very wide orbit planets down to an Earth mass, from the MOA-II microlensing survey in 2006-2014. Six events are likely to be due to planets with Einstein radius crossing times t E &lt; 0.5 days, and the shortest has t E = 0.057 ± 0.016 days and an angular Einstein radius of θ E = 0.90 ± 0.14 μas. We measure the detection efficiency depending on both t E and θ E with image-level simulations for the first time. These short events are well modeled by a power-law mass function, ${{dN}}_{4}/d\mathrm{log}M={({2.18}_{-1.40}^{+0.52})\times (M/8\,{M}_{\oplus })}^{-{\alpha }_{4}}$ dex-1 star-1 with ${\alpha }_{4}={0.96}_{-0.27}^{+0.47}$ for M/M ⊙ &lt; 0.02. This implies a total of $f={21}_{-13}^{+23}$ FFPs or very wide orbit planets of mass 0.33 &lt; M/M ⊕ &lt; 6660 per star, with a total mass of ${80}_{-47}^{+73}{M}_{\oplus }$ star-1. The number of FFPs is ${19}_{-13}^{+23}$ times the number of planets in wide orbits (beyond the snow line), while the total masses are of the same order. This suggests that the FFPs have been ejected from bound planetary systems that may have had an initial mass function with a power-law index of α ~ 0.9, which would imply a total mass of ${171}_{-52}^{+80}{M}_{\oplus }$ star-1. This model predicts that Roman Space Telescope will detect ${988}_{-566}^{+1848}$ FFPs with masses down to that of Mars (including ${575}_{-424}^{+1733}$ with 0.1 ≤ M/M ⊕ ≤ 1). The Sumi et al. large Jupiter-mass FFP population is excluded.

Keywords: Gravitational microlensing exoplanet detection, Galactic bulge, Exoplanet astronomy, Free floating planets, Gravitational microlensing
The Mass-Temperature Relation for B and Early A Stars Based on International Ultraviolet Explorer Spectra of Detached Eclipsing Binaries. Ultraviolet spectra were taken of 25 detached eclipsing binaries (DEBs) with spectral types O, B, and early A with the International Ultraviolet Explorer satellite in the 1150-1900 Å region. The spectra were compared with BOSZ model atmospheres. The composite spectra of the DEBs were modeled by a combination of models representing the hot and cool components, and the temperatures of the hottest components of the systems were determined. From these temperatures a direct mass-temperature relation was obtained for stars close to the main sequence with solar metallicity for B and early A stars: log M/M ⊙ = -5.90 ± 0.27 + (1.56 ± 0.07) × log T. This relation allows a mass to be inferred for comparable stars from an ultraviolet spectrum. The five chemically peculiar Am stars in the sample have larger radii than normal A stars of the same mass.

Keywords: Fundamental parameters of stars
Binary Star Evolution in Different Environments: Filamentary, Fractal, Halo, and Tidal Tail Clusters. Using membership of 85 open clusters from previous studies based on Gaia Data Release 3 data, we identify binary candidates in the color-magnitude diagram for systems with mass ratio q &gt; 0.4. The binary fraction is corrected for incompleteness at different distances due to the Gaia angular resolution limit. We find a decreasing binary fraction with increasing cluster age, with substantial scatter. For clusters with a total mass &gt;200 M ⊙, the binary fraction is independent of cluster mass. The binary fraction depends strongly on stellar density. Among the four types of cluster environments, the lowest-density filamentary and fractal stellar groups have the highest mean binary fraction: 23.6% and 23.2%, respectively. The mean binary fraction in tidal tail clusters is 20.8% and is lowest in the densest halo-type clusters: 14.8%. We find clear evidence of early disruptions of binary stars in the cluster sample. The radial binary fraction depends strongly on the clustercentric distance across all four types of environments, with the smallest binary fraction within the half-mass radius r h and increasing toward a few r h. Only hints of mass segregation are found in the target clusters. The observed amounts of mass segregation are not significant enough to generate a global effect inside the target clusters. We evaluate the bias of unresolved binary systems (assuming a primary mass of 1 M ⊙) in 1D tangential velocity, which is 0.1-1 km s-1. Further studies are required to characterize the internal star cluster kinematics using Gaia proper motions.

Keywords: Open star clusters, Dynamical evolution, Binary stars, Star clusters
The Kiloparsec-scale Influence of the AGN in NGC 1068 with SALT RSS Fabry-Pérot Spectroscopy. We present Fabry-Pérot (FP) imaging and longslit spectroscopy of the nearby Seyfert II galaxy NGC 1068 using the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT) to observe the impact of the central active galactic nucleus (AGN) on the ionized gas in the galaxy on kiloparsec scales. With SALT RSS FP we are able to observe the Hα + [N II] emission line complex over a ~2.6 arcmin2 field of view. Combined with the longslit observation, we demonstrate the efficacy of FP spectroscopy for studying nearby Type II Seyfert galaxies and investigate the kiloparsec-scale ionized gas in NGC 1068. We confirm the results of previous work from the TYPHOON/Progressive Integral Step Method survey that the kiloparsec-scale ionized features in NGC 1068 are driven by AGN photoionization. We analyze the spatial variation of the AGN intensity to put forward an explanation for the shape and structure of the kiloparsec-scale ionization features. Using a toy model, we suggest the ionization features may be understood as a light echo from a burst of enhanced AGN activity ~2000 yr ago. *Based on observations made with the Southern African Large Telescope (SALT).

Keywords: AGN host galaxies, Seyfert galaxies
A Hierarchical Bayesian Framework for Inferring the Stellar Obliquity Distribution. Stellar obliquity, the angle between a planet's orbital axis and its host star's spin axis, traces the formation and evolution of a planetary system. In transiting-exoplanet observations, only the sky-projected stellar obliquity can be measured, but this can be deprojected using an estimate of the stellar obliquity. In this paper, we introduce a flexible, hierarchical Bayesian framework that can be used to infer the stellar obliquity distribution solely from sky-projected stellar obliquities, including stellar inclination measurements when available. We demonstrate that while a constraint on the stellar inclination is crucial for measuring the obliquity of an individual system, it is not required for robust determination of the population-level stellar obliquity distribution. In practice, the constraints on the stellar obliquity distribution are mainly driven by the sky-projected stellar obliquities. When applying the framework to all systems with measured sky-projected stellar obliquity, which are mostly hot Jupiter systems, we find that the inferred population-level obliquity distribution is unimodal and peaked at zero degrees. Misaligned systems have nearly isotropic stellar obliquities with no strong clustering near 90°. The diverse range of stellar obliquities prefers dynamic mechanisms, such as planet-planet scattering after a convergent disk migration, which could produce both prograde and retrograde orbits of close-in planets with no strong inclination concentrations other than that at 0°.

Keywords: Exoplanet dynamics, Bayesian statistics, Exoplanets
A Search for Gas-Rich Dwarf Galaxies in the Local Universe with ALFALFA and the WIYN One Degree Imager. We present results from an optical search for Local Group dwarf galaxy candidates associated with the Ultra-Compact High Velocity Clouds (UCHVCs) discovered by the ALFALFA neutral hydrogen survey. The ALFALFA UCHVCs are isolated, compact H I clouds with projected sizes, velocities, and estimated H I masses that suggest they may be nearby dwarf galaxies, but that have no clear counterpart in existing optical survey data. We observed 26 UCHVCs with the WIYN 3.5 m telescope and One Degree Imager (ODI) in two broadband filters and searched the images for resolved stars with properties that match those of stars in typical dwarf galaxies at distances &lt;2.5 Mpc. We identify one promising dwarf galaxy candidate at a distance of ∼570 kpc associated with the UCHVC AGC 268071, and five other candidates that may deserve additional follow-up. We carry out a detailed analysis of ODI imaging of a UCHVC that is close in both projected distance and radial velocity to the outer-halo Milky Way globular cluster Pal 3. We also use our improved detection methods to reanalyze images of five UCHVCs that were found to have possible optical counterparts during the first phase of the project, and confirm the detection of a possible stellar counterpart to the UCHVC AGC 249525 at an estimated distance of ∼2 Mpc. We compare the optical and H I properties of the dwarf galaxy candidates to the results from recent theoretical simulations that model satellite galaxy populations in group environments, as well as to the observed properties of galaxies in and around the Local Group.

Keywords: Local Group, Stellar photometry, Optical observation, Extragalactic radio sources, Dwarf galaxies, Neutral hydrogen clouds, Sloan photometry
Modeling Apsidal Motion in Eclipsing Binaries Using ELC. Apsidal motion is the precession of the line of apsides in the orbit of a binary star due to perturbations from General Relativity (GR), tides, or third-body interactions. The rate of precession due to tidal effects depends on the interior structures of the stars, and as a result, binaries in which this precession occurs are of great interest. Apsidal motion is observed through the analysis of eclipse times, which reveal small changes in the average interval between successive primary and secondary eclipses, taking all available observed times of eclipse and yielding an estimate of the apsidal rate. Given that this is a single observed quantity, various degeneracies are unavoidably present. Ideally, one would have a model that predicts eclipse times given the orbital and stellar parameters. These parameters for a given binary could then be computed using least squares, provided a suitably large number of eclipse times. Here we use the eclipsing light curve (ELC) program as such a model. The Newtonian equations of motion with additional force terms accounting for GR contributions and tidal distortions are integrated, yielding precise sky positions as a function of time. Times of mid-eclipse and instantaneous orbital elements are computed as a function of time. In this paper, we outline the method and compare numerically computed apsidal rates with standard formulae using a set of 15 binaries based on real systems. For our simulated systems, the derived apsidal rates agree with the standard formula.

Keywords: Apsidal motion
What's the Difference? The Potential for Convolutional Neural Networks for Transient Detection without Template Subtraction. We present a study of the potential for convolutional neural networks (CNNs) to enable separation of astrophysical transients from image artifacts, a task known as "real-bogus" classification, without requiring a template-subtracted (or difference) image, which requires a computationally expensive process to generate, involving image matching on small spatial scales in large volumes of data. Using data from the Dark Energy Survey, we explore the use of CNNs to (1) automate the real-bogus classification and (2) reduce the computational costs of transient discovery. We compare the efficiency of two CNNs with similar architectures, one that uses "image triplets" (templates, search, and difference image) and one that takes as input the template and search only. We measure the decrease in efficiency associated with the loss of information in input, finding that the testing accuracy is reduced from ~96% to ~91.1%. We further investigate how the latter model learns the required information from the template and search by exploring the saliency maps. Our work (1) confirms that CNNs are excellent models for real-bogus classification that rely exclusively on the imaging data and require no feature engineering task and (2) demonstrates that high-accuracy (&gt;90%) models can be built without the need to construct difference images, but some accuracy is lost. Because, once trained, neural networks can generate predictions at minimal computational costs, we argue that future implementations of this methodology could dramatically reduce the computational costs in the detection of transients in synoptic surveys like Rubin Observatory's Legacy Survey of Space and Time by bypassing the difference image analysis entirely.

Keywords: Convolutional neural networks, Transient detection, Astronomical methods
OGLE-2019-BLG-0825: Constraints on the Source System and Effect on Binary-lens Parameters Arising from a Five-day Xallarap Effect in a Candidate Planetary Microlensing Event. We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from the best-fit static binary-lens model exist and a xallarap effect can fit the residuals very well and significantly improves χ 2 values. On the other hand, by including the xallarap effect in our models, we find that binary-lens parameters such as mass ratio, q, and separation, s, cannot be constrained well. However, we also find that the parameters for the source system such as the orbital period and semimajor axis are consistent between all the models we analyzed. We therefore constrain the properties of the source system better than the properties of the lens system. The source system comprises a G-type main-sequence star orbited by a brown dwarf with a period of P ~ 5 days. This analysis is the first to demonstrate that the xallarap effect does affect binary-lens parameters in planetary events. It would not be common for the presence or absence of the xallarap effect to affect lens parameters in events with long orbital periods of the source system or events with transits to caustics, but in other cases, such as this event, the xallarap effect can affect binary-lens parameters.

Keywords: Gravitational microlensing, Brown dwarfs, Xallarap effect
Understanding the Capability of Future Direct-imaging Observations to Quantify Atmospheric Chemical Effects of Stellar Proton Events. Models developed for Earth are often applied in exoplanet contexts. Validation in extraterrestrial settings can provide an important test of model realism and increase our confidence in model predictions. NASA's upcoming space-based IROUV telescope will provide unprecedented opportunities to perform such tests. Here, we use the Planetary Spectrum Generator to simulate IROUV reflected-light spectroscopic observations of flare-driven photochemical changes produced by the Whole Atmosphere Community Climate Model, part of the Community Earth System Model framework. We find that NO2 is the most observable gas to target, and integrating the signal for two days following the flare and comparing to a baseline of preflare data would achieve the highest signal-to-noise ratio. The NO2 response is much larger for K-star tidally locked planets than G-star rapidly rotating planets and does not depend strongly on O2 level. The NO2 response should be observable for planets within 3-4 pc independent of the phase angle since the amount of reflected light is larger at smaller phases, but the NO2 concentration is low near the substellar point. This work outlines a methodology for validating and ground-truthing atmospheric chemistry models developed for Earth that could be useful for the numerical exploration of exoplanets.

Keywords: Exoplanet atmospheric composition , Direct imaging, Radiative transfer, Radiative transfer simulations, Exoplanet atmospheres
Is There an Earth-like Planet in the Distant Kuiper Belt?. The orbits of trans-Neptunian objects (TNOs) can indicate the existence of an undiscovered planet in the outer solar system. Here we used N-body computer simulations to investigate the effects of a hypothetical Kuiper Belt planet (KBP) on the orbital structure of TNOs in the distant Kuiper Belt beyond ~50 au. We used observations to constrain model results, including the well-characterized Outer Solar System Origins Survey (OSSOS). We determined that an Earth-like planet (m ~ 1.5-3 M ⊕) located on a distant (semimajor axis a ~ 250-500 au, perihelion q ~ 200 au) and inclined (i ~ 30°) orbit can explain three fundamental properties of the distant Kuiper Belt: a prominent population of TNOs with orbits beyond Neptune's gravitational influence (i.e., detached objects with q &gt; 40 au), a significant population of high-i objects (i &gt; 45°), and the existence of some extreme objects with peculiar orbits (e.g., Sedna). Furthermore, the proposed KBP is compatible with the existence of identified gigayear-stable TNOs in the 2:1, 5:2, 3:1, 4:1, 5:1, and 6:1 Neptunian mean motion resonances. These stable populations are often neglected in other studies. We predict the existence of an Earth-like planet and several TNOs on peculiar orbits in the outer solar system, which can serve as observationally testable signatures of the putative planet's perturbations.

Keywords: Neptune, Kuiper belt, Solar system planets, Detached objects, Resonant Kuiper belt objects, Solar system, Scattered disk objects, Trans-Neptunian objects
Rovibrational Spectroscopy of CI Tau-Evidence of a Multicomponent Eccentric Disk Induced by a Planet. CI Tau is currently the only T Tauri star with an inner protoplanetary disk that hosts a planet, CI Tau b, that has been detected by a radial velocity survey. This provides the unique opportunity to study disk features that were imprinted by that planet. We present multiepoch spectroscopic data, taken with NASA IRTF in 2022, of the 12CO and hydrogen Pfβ line emissions spanning nine consecutive nights, which is the proposed orbital period of CI Tau b. We find that the star's accretion rate varied according to that nine-day period, indicative of companion-driven accretion. Analysis of the 12CO emission lines reveals that the disk can be described with an inner and an outer component spanning orbital radii 0.05-0.13 au and 0.15-1.5 au, respectively. Both components have eccentricities of about 0.05 and arguments of periapsis that are oppositely aligned. We present a proof-of-concept hydrodynamic simulation that shows that a massive companion on a similarly eccentric orbit can recreate a similar disk structure. Our results allude to such a companion being located at an orbital distance of around 0.14 au. However, this planet's orbital parameters may be inconsistent with those of CI Tau b, whose high eccentricity is likely not compatible with the low disk eccentricities inferred by our model.

Keywords: Accretion, High resolution spectroscopy, Planetary-disk interactions, Infrared spectroscopy, Hot Jupiters, Protoplanetary disks, Stellar accretion, Circumstellar disks
ACCESS, LRG-BEASTS, and MOPSS: Featureless Optical Transmission Spectra of WASP-25b and WASP-124b. We present new optical transmission spectra for two hot Jupiters: WASP-25b (M = 0.56 M  J ; R = 1.23 R  J ; P = 3.76 days) and WASP-124b (M = 0.58 M  J ; R = 1.34 R  J ; P = 3.37 days), with wavelength coverages of 4200-9100 Å and 4570-9940 Å, respectively. These spectra are from the ESO Faint Object Spectrograph and Camera (v.2) mounted on the New Technology Telescope and Inamori-Magellan Areal Camera &amp; Spectrograph on Magellan Baade. No strong spectral features were found in either spectra, with the data probing 4 and 6 scale heights, respectively. Exoretrievals and PLATON retrievals favor stellar activity for WASP-25b, while the data for WASP-124b did not favor one model over another. For both planets the retrievals found a wide range in the depths where the atmosphere could be optically thick (~0.4 μ-0.2 bars for WASP-25b and 1.6 μ-32 bars for WASP-124b) and recovered a temperature that is consistent with the planets' equilibrium temperatures, but with wide uncertainties (up to ±430 K). For WASP-25b, the models also favor stellar spots that are ~500-3000 K cooler than the surrounding photosphere. The fairly weak constraints on parameters are owing to the relatively low precision of the data, with an average precision of 840 and 1240 ppm per bin for WASP-25b and WASP-124b, respectively. However, some contribution might still be due to an inherent absence of absorption or scattering in the planets' upper atmospheres, possibly because of aerosols. We attempt to fit the strength of the sodium signals to the aerosol-metallicity trend proposed by McGruder et al., and find WASP-25b and WASP-124b are consistent with the prediction, though their uncertainties are too large to confidently confirm the trend.

Keywords: Exoplanet atmospheric composition , Hot Jupiters, Stellar activity, Exoplanet astronomy, Exoplanet atmospheres
The Molecular Clouds in a Section of the Third Galactic Quadrant: Observational Properties and Chemical Abundance Ratio between CO and its Isotopologues. We compare the observational properties between 12CO, 13CO, and C18O and summarize the observational parameters based on a 7069-cloud sample from the Milky Way Imaging Scroll Painting CO survey in a section of the third Galactic quadrant. We find that the 13CO angular area ( ${A}_{{}^{13}\mathrm{CO}}$ ) generally increases with that of 12CO ( ${A}_{{}^{12}\mathrm{CO}}$ ), and the ratio of ${A}_{{}^{13}\mathrm{CO}}$ to ${A}_{{}^{12}\mathrm{CO}}$ is 0.38 by linear fitting. We find that the 12CO and 13CO flux are tightly correlated as ${F}_{{}^{13}\mathrm{CO}}=0.17\,{F}_{{}^{12}\mathrm{CO}}$ with both fluxes calculated within the 13CO-bright region. This indicates that the abundance ${X}_{{}^{13}\mathrm{CO}}$ is a constant as ${6.5}_{-0.5}^{+0.1}\times {10}^{-7}$ for all samples under the assumption of local thermodynamic equilibrium (LTE). Additionally, we observed that the X-factor is approximately constant in a large sample of molecular clouds. Similarly, we find ${F}_{{{\rm{C}}}^{18}{\rm{O}}}=0.11\,{F}_{{}^{13}\mathrm{CO}}$ with both fluxes calculated within the C18O-bright region, which indicates that the abundance ratio ${X}_{{}^{13}\mathrm{CO}}/{X}_{{{\rm{C}}}^{18}{\rm{O}}}$ stays at the same value of ${9.7}_{-0.8}^{+0.6}$ across the molecular clouds under the LTE assumption. The linear relationships of ${F}_{{}^{12}\mathrm{CO}}$ versus ${F}_{{}^{13}\mathrm{CO}}$ and ${F}_{{}^{13}\mathrm{CO}}$ versus ${F}_{{{\rm{C}}}^{18}{\rm{O}}}$ hold not only for the 13CO-bright region and C18O-bright region, but also for the entire molecular cloud scale with a lower flux ratio. The abundance ratio ${X}_{{}^{13}\mathrm{CO}}/{X}_{{{\rm{C}}}^{18}{\rm{O}}}$ inside the clouds shows a strong correlation with the column density and temperature. This indicates that the ratio ${X}_{{}^{13}\mathrm{CO}}/{X}_{{{\rm{C}}}^{18}{\rm{O}}}$ is dominated by a combination of chemical fractionation, selective dissociation, and the self-shielding effect inside the clouds.

Keywords: Abundance ratios, Molecular clouds, Chemical abundances