Sazuna/UAT_keywords huggingface dataset:
PhotoD with LSST: Stellar Photometric Distances Out to the Edge of the Galaxy. As demonstrated with the Sloan Digital Sky Survey (SDSS), Pan-STARRS, and most recently with Gaia data, broadband near-UV to near-IR stellar photometry can be used to estimate distance, metallicity, and interstellar dust extinction along the line of sight for stars in the Galaxy. Anticipating photometric catalogs with tens of billions of stars from Rubin's Legacy Survey of Space and Time (LSST), we present a Bayesian model and pipeline that build on previous work and can handle LSST-sized datasets. Likelihood computations utilize MIST/Dartmouth isochrones and priors are derived from TRILEGAL-based simulated LSST catalogs from P. Dal Tio et al. The computation speed is about 10 ms per star on a single core for both optimized grid search and Markov Chain Monte Carlo methods; we show in a companion paper by K. Mrakovčić et al. how to utilize neural networks to accelerate this performance by up to an order of magnitude. We validate our pipeline, named PhotoD (in analogy with photo-z, photometric redshifts of galaxies) using both simulated catalogs and SDSS, DECam, and Gaia photometry. We intend to make LSST-based value-added PhotoD catalogs publicly available via the Rubin Science Platform with every LSST data release.

Keywords: Distance measure, Distance indicators, Reddening law, Extinction, Interstellar extinction, Stellar distance
Impact of Annually Variable Dust Activity on the Recession of the Martian South Polar Seasonal Cap. Suspended dust is a vital component of Martian climatic system and its temporal-spatial variation can influence the recession of the South Polar Seasonal Cap (SPSC). However, dust activity varies across different stages and years, affecting the SPSC recession process differently. Continuous observations of SPSC/South Polar Residual Cap (SPRC) across several Martian years, alongside segmented analyses of annual dust activity, will provide new insights into the climate conditions of Martian south polar region. Here, we performed a combined analysis on the extents of SPSC from MY28-MY31 and MY36, together with the concurrent Martian atmospheric optical thickness, to assess the influence of dust activity at various recession time steps. Results show that dust activity peaks in both spring and summer can impact the SPSC/SPRC recession. The recession process is accelerated if the dust activity peak occurs earlier. If the timing of the peak dust activity is identical, the intensity of the dust activity influences the recession. Specific regions, such as the "Cryptic Region" and the Mountains of Mitchel, respond uniquely to dust activity. Higher dust intensity slows the recession of the Cryptic Region, while the SPSC in the Mountains of Mitchel area shows variability in recession timing based on local dust activity intensity. This research provides observational constraints that enhance our understanding of Martian atmospheric circulation and can potentially aid the future development of polar dust activity models.

Keywords: Polar caps, Mars, Planetary climates
Astronomaly Protege: Discovery through Human-machine Collaboration. Modern telescopes generate catalogs of millions of objects with the potential for new scientific discoveries, but this is beyond what can be examined visually. Here we introduce ASTRONOMALY: PROTEGE, an extension of the general-purpose machine-learning-based active anomaly detection framework ASTRONOMALY. PROTEGE is designed to provide well-selected recommendations for visual inspection, based on a small amount of optimized human labeling. The resulting sample contains rare or unusual sources that are simultaneously as diverse as the human trainer chooses and of scientific interest to them. We train PROTEGE on images from the MeerKAT Galaxy Cluster Legacy Survey, leveraging the self-supervised deep learning algorithm Bootstrap Your Own Latent to find a low-dimensional representation of the radio galaxy cutouts. By operating in this feature space, PROTEGE is able to recommend interesting sources with completely different morphologies in image space to those it has been trained on. This provides important advantages over similarity searches, which can only find more examples of known sources, or blind anomaly detection, which selects unusual but not necessarily scientifically interesting sources. Using an evaluation subset, we show that, with minimal training, PROTEGE provides excellent recommendations and find that it is even able to recommend sources that the authors missed. We briefly highlight some of PROTEGE's top recommendations, which include X- and circular-shaped sources, filamentary structures, and one-sided structures. These results illustrate the power of an optimized human-machine collaboration, such as PROTEGE, to make unexpected discoveries in samples beyond human-accessible scales.

Keywords: Open source software, Astronomy software, Extragalactic radio sources, Astronomy data analysis, Radio active galactic nuclei
COSMIC's Large-scale Search for Technosignatures during the VLA Sky Survey: Survey Description and First Results. Developing algorithms to search through data efficiently is a challenging part of searching for signs of technology beyond our solar system. We have built a digital signal processing system and computer cluster on the backend of the Karl G. Jansky Very Large Array (VLA) in New Mexico in order to search for signals throughout the Galaxy consistent with our understanding of artificial radio emissions. In our first paper, we described the system design and software pipelines. In this paper, we describe a postprocessing pipeline to identify persistent sources of interference, filter out false positives, and search for signals not immediately identifiable as anthropogenic radio frequency interference during the VLA Sky Survey. As of 2024 September 1, the Commensal Open-source Multi-mode Interferometric Cluster had observed more than 950,000 unique pointings. This paper presents the strategy we employ when commensally observing during the VLA Sky Survey and a postprocessing strategy for the data collected during the survey. To test this postprocessing pipeline, we searched toward 511 stars from the Gaia catalog with coherent beams. This represents about 30 minutes of observation during the VLA Sky Survey, where we typically observe about 2000 sources hr–1 in the coherent beamforming mode. We did not detect any unidentifiable signals, setting isotropic power limits ranging from 1011 to 1016 W.

Keywords: GPU computing, Astrobiology, Search for extraterrestrial intelligence
On the Observational Solid Angle in Estimating the Moon-based Disk-integrated Earth Outgoing Longwave Radiation. Equipping sensors on the lunar surface would enable the capture of Earth's outgoing longwave radiation (OLR) from nearly an entire hemisphere. However, the Earth's nonsphericity would profoundly impact the observational solid angle, thereby influencing the disk-integrated Earth OLR estimation. This study analyzes the impact of the Earth's ellipsoidal shape on the OLR estimation by examining the effects of the observational solid angle. In particular, an expansion-series-based method is proposed for calculating the observational solid angle, avoiding complex numerical integration. Three critical issues are analyzed. (1) Comparing the observational solid angles calculated by using an Earth ellipsoidal model versus those obtained by adjusting the Earth's radius. We find that adjusting the Earth's radius can approximate the results based on an Earth ellipsoidal model, offering insights into parameterizing the observational solid angle. (2) Parameterizing the observational solid angle through series expansion, which is validated by comparing the associated results to those from numerical integrations. The observational solid angle is parameterized into two components: one is attributable to a variable Earth radius and another is related to the nadir point's latitude and the Earth–Moon distance. (3) Guiding parameter selection for observational solid angle estimation. These findings enhance our understanding of disk-integrated Earth OLR estimates and provide a unique tool for establishing benchmarks for the Earth samples needed in the study of habitable planets, thereby contributing to sustainable development.

Keywords: Earth atmosphere, Earth (planet), Remote sensing, Exoplanet detection methods, Habitable planets
Orbits of Six Triple Systems. Joint analysis of position measurements and radial velocities of six triple stellar systems is conducted to determine their inner and/or outer orbits. Accumulation of such data is needed to study the architecture of stellar hierarchies and its relation to the formation mechanisms. The inner periods in the six systems (HIP 11783, 64836, 72423, 84720, 89234, and 105404) range from 0.5 days to 44 yr. The shortest outer period of 3.34 yr is found in the compact triple HIP 105404 (BS Ind). The resolved triple system HIP 64836 has comparable inner and outer periods (5 and 30 yr), placing it near the limit of dynamical stability, while its quasi-circular and coplanar orbits suggest a 1:6 mean motion resonance. The periods in HIP 89234 (44 and ~450 yr) are also comparable, but the mutual orbit inclination is large, 54°. Masses of the components are estimated and each system is discussed individually.

Keywords: Spectroscopic binary stars, Trinary stars, Visual binary stars, Multiple stars
Interior Convection Regime, Host Star Luminosity, and Predicted Atmospheric CO<SUB>2</SUB> Abundance in Terrestrial Exoplanets. Terrestrial planets in the habitable zone (HZ) of Sun-like stars are priority targets for detection and observation by the next generation of space telescopes. Earth's long-term habitability may have been tied to the geological carbon cycle, a process critically facilitated by plate tectonics. In the modern Earth, plate motion corresponds to a mantle convection regime called mobile lid. The alternate, stagnant-lid regime is found on Mars and Venus, which may have lacked strong enough weathering feedback to sustain surface liquid water over geological timescales if initially present. Constraining observational strategies able to infer the most common regime in terrestrial exoplanets requires quantitative predictions of the atmospheric composition of planets in either regime. We use end-member models of volcanic outgassing and crust weathering for the stagnant- and mobile-lid convection regimes, which we couple to models of atmospheric chemistry and climate and ocean chemistry to simulate the atmospheric evolution of these worlds in the HZ. In our simulations under the two alternate regimes, we find that the fraction of planets possessing climates consistent with surface liquid water is virtually the same. Despite this unexpected similarity, we predict that a mission capable of detecting atmospheric CO2 abundance above 0.1 bar in 25 terrestrial exoplanets is extremely likely (≥95% of samples) to infer the dominant interior convection regime in that sample with strong evidence (10:1 odds). This offers guidance for the specifications of the Habitable Worlds Observatory NASA concept mission and other future missions capable of probing samples of habitable exoplanets.

Keywords: Extrasolar rocky planets, Exoplanets, Astrobiology, Planetary interior, Exoplanet atmospheres, Exoplanet atmospheric evolution
Hydrogen Cyanide in Comet C/2022 E3 (ZTF) from 3.4 mm Wave Spectra. The composition inside a comet nuclear can be detected through the molecular rotational emission lines at millimeter or submillimeter wavelengths. We observed a long-period comet C/2022 E3 (ZTF) using the Purple Mountain Observatory 13.7 m radio telescope at 3.4 mm during mid January and early February in 2023. From the observed spectra, the hydrogen cyanide (HCN)(J = 1–0) spectra lines was detected. The mean production rate of HCN is (8.30 ± 1.14) × 1025 molec. s‑1 in mid January and (3.91 ± 0.84) × 1025 molec. s‑1 in early February. we also estimated the upper limit of the production rate of HCO+. We obtained the abundance of HCN relative to water, (0.13 ± 0.02)% in mid January when C/2022 E3 (ZTF) got close to the Sun at 1.11 au, and (0.13 ± 0.03)% in early February at 1.16 au. Our conclusion leans toward E3 being similar to most comets, with the abundance of HCN remaining stable during our two observation periods.

Keywords: Submillimeter astronomy, Long period comets
Upper Limits on Stellar Companions to the Kepler-34 and Kepler-35 Systems. We obtained new spectra of Kepler-34 and Kepler-35 with Keck-HIRES—nearly a decade after these systems were originally characterized with this spectrograph and other instruments—to search for radial velocity (RV) trends from a potential third stellar-mass companion at long periods. For Kepler-34, we rule out coplanar stellar masses as low as 0.12M⊙ at an orbital period of ≲52 yr. For Kepler-35, we rule out stellar masses of 0.13M⊙ at orbital periods of ≲55 yr. Highly stable, extreme precision RV instruments, as well as improved methodologies in characterizing double-lined spectroscopic binaries that come with these new instruments, will provide an opportunity to push these mass limits lower in the future.

Keywords: Eclipsing binary stars, Radial velocity
An Investigation into the Variability of Luminous Blue Variable Stars with TESS. Luminous blue variables (LBVs) are enigmatic, evolved, massive stars. Their variability has been observed to be episodic with large eruptions, along with variations on timescales of days to decades. We have extracted light curves of 37 LBVs from the first 4 yr of the TESS mission. These light curves provide two years of photometric time series for stars in the LMC, with several months of data for Galactic or SMC targets. We analyze the Fourier properties of the stellar light curves to determine their characteristic frequencies and red noise amplitudes, comparing them to mass-loss parameters through Hα strength, and in the case of the LMC stars, B ‑ V color and luminosity as estimated by their apparent g magnitudes. We confirm the absence of correlation between any of the Fourier parameters and stellar parameters, implying that there is no trend in how these stars vary as measured with these photometric data, which may point toward these stars being an extension to the supergiant α Cygni variables and not a unique class of object with regards to their short-term variations.

Keywords: Early-type variable stars, Massive stars, Luminous blue variable stars, Alpha Cygni variable stars, S Doradus stars
A Refined Astrometric Approach Based on the Precision Premium and its Application to the Jupiter's Satellite Himalia. Since the advent of Gaia catalog, positional precision of a ground-based telescope can be greatly improved by correction of more subtle errors, including positional biases induced by atmospheric turbulence, and some instrumental factors such as geometric distortion and the charge transfer efficiency. In our previous work, the correlation of positional precision as a function of two objects' separation is studied and found to be effectively modeled by a sigmoidal function, which provides a good description of this rule. Based on our understanding of the physics of the precision premium, we further refine the astrometric approach in this paper, which determines a target's position in a small region through a weighting scheme. Based on the reductions of the observations of several open clusters and Himalia, Jupiter's largest irregular satellite, the refined approach has demonstrated substantial improvements in positional precision, particularly in scenarios where a sufficient number of reference stars are present in dense fields. We suspect that the contributing factor might be the refined approach's ability to mitigate not only turbulence effects but instrumental effects as well, prevalent among closely spaced star images, given that the approach focuses on localized measurements within a confined area.

Keywords: Astronomical techniques, CCD observation, Natural satellites (Solar system), Photographic astrometry
A Radio-interferometric Imaging Method Based on the Wavelet Tight Frame. Reconstructing the signal from measured visibilities in radio interferometry is an ill-posed inverse problem. In this paper, we present a novel radio-interferometric imaging method based on the wavelet tight frame aimed at efficiently obtaining an accurate solution. In our approach, the signal is sparsely represented by the directional tensor product complex tight framelets, which can effectively capture the texture and shape features of the images. To enhance computational efficiency, we employ the projected fast iterative soft-thresholding algorithm for solving the l1-norm minimization problem. Several simulation experiments are carried out to verify the effectiveness and performance of the proposed method.

Keywords: Radio interferometry, Radio interferometers
A Candidate High-velocity Exoplanet System in the Galactic Bulge. We present an analysis of adaptive optics images from the Keck I telescope of the microlensing event MOA-2011-BLG-262. The original discovery paper by Bennett et al. reports two possibilities for the lens system: a nearby gas giant lens with an exomoon companion or a very low-mass star with a planetary companion in the Galactic bulge. The ∼10 yr baseline between the microlensing event and the Keck follow-up observations allows us to detect the faint candidate lens host (star) at K = 22.3 mag and confirm the distant lens system interpretation. The combination of the host star brightness and light curve parameters yields host star and planet masses of Mhost = 0.19 ± 0.03 M⊙ and mp = 28.92 ± 4.75 M⊕ at a distance of DL = 7.49 ± 0.91 kpc. We perform a multiepoch cross reference to Gaia Data Release 3 and measure a transverse velocity for the candidate lens system of vL = 541.31 ± 65.75 km s‑1. We conclude this event consists of the highest-velocity exoplanet system detected to date, and also the lowest-mass microlensing host star with a confirmed mass measurement. The high-velocity nature of the lens system can be definitively confirmed with an additional epoch of high-resolution imaging at any time now. The methods outlined in this work demonstrate that the Roman Galactic Exoplanet Survey will be able to securely measure low-mass host stars in the bulge.

Keywords: Gravitational microlensing, High-resolution microlensing event imaging, Adaptive optics, Exoplanets
The Heating Efficiency of Hot Jupiters from a Data-driven Perspective. The inflated radii of hot Jupiters have been explored by various theoretical mechanisms. By connecting planetary thermal evolution models with the observed properties of hot Jupiters using hierarchical Bayesian models, a theoretical parameter called the heating efficiency has been introduced to describe the heating of the interiors of these planets. Previous studies have shown that the marginal distribution of this heating-efficiency parameter has a single-peak distribution along the planetary equilibrium temperature (Teq). Since the observed properties of hot Jupiters are the foundation of these Bayesian inference models, there must be a corresponding feature in the observed data that leads to the inferred single-peak distribution of the heating efficiency. This study aims to find the underlying cause of the single-peak heating-efficiency distribution without relying on specific theoretical models. By analyzing the relationships between different observed physical properties, we obtain a similar single-peak distribution of the radius expansion efficiency of hot Jupiters along Teq, which can be explained by the correlation with the stellar effective temperature. However, a detailed investigation suggests that this single-peak distribution is actually the result of straightforward physical processes. Specifically, the increase in heating efficiency can be attributed to the increase in incident stellar flux, while the decrease in heating efficiency can be attributed to the rise in the gravitational binding energy associated with the increase in planetary mass.

Keywords: Bayesian statistics, Astronomy data analysis, Extrasolar gaseous giant planets, Hot Jupiters
PAH Feature Ratios around Stellar Clusters and Associations in 19 Nearby Galaxies. We present a comparison of observed polycyclic aromatic hydrocarbon (PAH) feature ratios in 19 nearby galaxies with a grid of theoretical expectations for near- and mid-infrared dust emission. The PAH feature ratios are drawn from Cycle 1 JWST observations and are measured for 7224 stellar clusters and 29,176 stellar associations for which we have robust ages and mass estimates from Hubble Space Telescope five-band photometry. Though there are galaxy-to-galaxy variations, the observed PAH feature ratios largely agree with the theoretical models, particularly those that are skewed toward more ionized and larger PAH size distributions. For each galaxy we also extract PAH feature ratios for 200 pc wide circular regions in the diffuse interstellar medium, which serve as a noncluster/association control sample. Compared to what we find for stellar clusters and associations, the 3.3 μm/7.7 μm and 3.3 μm/11.3 μm ratios from the diffuse interstellar medium are ∼0.10–0.15 dex smaller. When the observed PAH feature ratios are compared to the radiation field hardness as probed by the [O III]/Hβ ratio, we find anticorrelations for nearly all galaxies in the sample. These results together suggest that the PAH feature ratios are driven by the shape and intensity of the radiation field and that the smallest PAHs—observed via JWST F335M imaging—are increasingly "processed" or destroyed in regions with the most intense and hard radiation fields.

Keywords: Polycyclic aromatic hydrocarbons, Galaxies, Star clusters
Ground-based Reconnaissance Observations of 21 Exoplanet Atmospheres with the Exoplanet Transmission Spectroscopy Imager. One of the most prolific methods of studying exoplanet atmospheres is transmission spectroscopy, which measures the difference between the depth of an exoplanet's transit signal at various wavelengths and attempts to correlate the depth changes to potential features in the exoplanet's atmosphere. Here we present reconnaissance observations of 21 exoplanet atmospheres measured with the Exoplanet Transmission Spectroscopy Imager (ETSI), a recently deployed spectrophotometer on the McDonald Observatory Otto Struve 2.1 m telescope. ETSI measurements are mostly free of systematics through the use of a novel observing technique called common-path multiband imaging (CMI), which has been shown to achieve photometric color precision on par with space-based observations (300 ppm or 0.03%). This work also describes the various statistical tests performed on the data to evaluate the efficacy of the CMI method and the ETSI instrument in combination. We find that none of the eight comparisons of exoplanet atmospheres measured with ETSI and other observatories (including the Hubble Space Telescope) provide evidence that the spectra are statistically dissimilar. These results suggest that ETSI can provide initial transmission spectroscopy observations for a fraction of the observational and monetary overhead previously required to detect an exoplanet's atmosphere. Ultimately these reconnaissance observations increase the number of planets with transmission spectroscopy measurements by ~10% and provide an immediate prioritization of 21 exoplanets for future follow-up with more precious observatories, such as the James Webb Space Telescope. The reconnaissance spectra are available through the Filtergraph visualization portal at the URL https://filtergraph.com/etsi/.

Keywords: Astronomical instrumentation, Exoplanet atmospheres, Multi-color photometry