Sazuna/UAT_keywords huggingface dataset:
The Thermal Emission Spectrum of the Nearby Rocky Exoplanet LTT 1445A b from JWST MIRI/LRS. The nearby transiting rocky exoplanet LTT 1445A b presents an ideal target for studying atmospheric retention in terrestrial planets orbiting M dwarfs. It is cooler than many rocky exoplanets yet tested for atmospheres, receiving a bolometric instellation similar to Mercury's. Previous transmission spectroscopy ruled out a light H/He-dominated atmosphere but could not distinguish between a bare-rock, a high-MMW, nor a cloudy atmosphere. We present new secondary eclipse observations using JWST's MIRI/LRS, covering the 5─12 μm range. From these observations, we detect a broadband secondary eclipse depth of 41 ± 9 ppm and measure a mid-eclipse timing consistent with a circular orbit (at 1.7σ). From its emission spectrum, the planet's dayside brightness temperature is constrained to 525 ± 15 K, yielding a temperature ratio relative to the maximum average dayside temperature from instant thermal reradiation by a rocky surface R =   = 0.952 ± 0.057, consistent with emission from a dark rocky surface. From an energy balance perspective, such a warm dayside temperature disfavors thick atmospheres, excluding ∼100 bar atmospheres with Bond albedo &gt;0.08 at the 3σ level. Furthermore, forward modeling of atmospheric emission spectra disfavor simple 100% CO2 atmospheres with surface pressures of 1, 10, and 100 bar at 4.2σ, 6.6σ, and 6.8σ confidence, respectively. These results suggest that LTT 1445A b lacks a very thick CO2 atmosphere, possibly due to atmospheric erosion driven by stellar activity. However, the presence of a moderately thin atmosphere (similar to those on Mars, Titan, or Earth) remains uncertain.

Keywords: Exoplanet astronomy, Astrobiology, Planetary atmospheres, Exoplanet atmospheres
A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPS. Structures in the magnetoionic medium exist across a wide range of angular sizes owing to large-scale magnetic fields coherent over the Galactic spiral arms combined with small-scale fluctuations in the magnetic field and electron density resulting from energy injection processes such as supernovae. For the first time, we produce diffuse Galactic synchrotron emission Faraday rotation maps covering all spatial scales down to   resolution for magnetic field studies. These maps complement total and polarized intensity maps combining single-antenna and interferometric data that have been produced, such as the Canadian Galactic Plane Survey (CGPS). Combined maps have sensitivity to large scales from the single-antenna component and angular resolution from the interferometric component. We combine Global Magneto-Ionic Medium Survey High-Band North single-antenna and CGPS aperture-synthesis polarization data after spatial filtering, producing Stokes Q and U maps for the four CGPS frequency channels. We calculate rotation measures (RMs) for all pixels using a linear fit to polarization angle versus wavelength squared. Smooth polarized emission regions require the large-scale sensitivity of the single antenna to illuminate the Faraday rotation, while aperture synthesis reveals small-scale RM variability. While these maps show magnetic field structures on the full range of spatial scales they probe, the RM values should be interpreted with caution, as the narrow λ2 coverage limits sensitivity to Faraday complexity. Despite this limitation of the CGPS 35 MHz bandwidth, we demonstrate that useful Faraday rotation information can be obtained from the combined data set, highlighting the important synergy between future broadband interferometric and single-antenna polarization surveys.

Keywords: Galaxy magnetic fields, Milky Way magnetic fields, Interstellar magnetic fields, Milky Way disk, Radio telescopes, Single-dish antennas, Radio observatories, Radio continuum emission, Radio interferometry, Polarimetry
The Herbig–Haro Outflow Content and Star-forming Environment of Circinus West and East. We report the results of a spatially compete, high-sensitivity survey for Herbig–Haro (HH) outflows in the Western and Eastern Circinus molecular clouds. We have detected 28 new HH objects in Circinus West, doubling the number known in this dark nebula. We have also discovered nine outflows in Circinus East, the first to be identified here. Although both Circinus West and East appear to be located at ∼800 pc, their morphologies are distinct. Circinus West shows filamentary structure, while Circinus East is dominated by amorphous dark clouds. North–East of Circinus East, an extended distribution of young stars is centered on the ∼6 Myr old open cluster ASCC 79, which may have triggered the sequential formation of younger surrounding populations. New transverse velocities from Gaia show two dynamically distinct stellar populations in Circinus East; their velocity distribution is consistent with an active cloud-cloud collision between material ejected by the formation of O and B stars in ASCC 79, and a dynamically similar interloping cloud. Given the similar distances to Circinus West and East, and the presence in both of HH objects—a phenomenon associated with stellar ages of ∼1 Myr—it is likely that these clouds are nominally related, but only Circinus East is subject to substantial feedback from the central cluster in the parent complex. This feedback appears to guide the morphology and evolution of Circinus East, resulting in a complex and possibly disruptive dynamical environment rich in star-formation potential that contrasts with the relatively quiescent environment in Circinus West.

Keywords: Herbig-Haro objects, Star forming regions, Star formation, Stellar associations
Lux: A Generative, Multioutput, Latent-variable Model for Astronomical Data with Noisy Labels. The large volume of spectroscopic data available now and from near-future surveys will enable high-dimensional measurements of stellar parameters and properties. Current methods for determining stellar labels from spectra use physics-driven models, which are computationally expensive and have limitations in their accuracy due to simplifications. While machine learning methods provide efficient paths toward emulating physics-based pipelines, they often do not properly account for uncertainties and have complex model structure, both of which can lead to biases and inaccurate label inference. Here we present Lux: a data-driven framework for modeling stellar spectra and labels that addresses prior limitations. Lux is a generative, multioutput, latent-variable model framework built on JAX for computational efficiency and flexibility. As a generative model, Lux properly accounts for uncertainties and missing data in the input stellar labels and spectral data and can either be used in probabilistic or discriminative settings. Here, we present several examples of how Lux can successfully emulate methods for precise stellar label determinations for stars ranging in stellar type and signal-to-noise ratio from the APOGEE survey. We also show how a simple Lux model is successful at performing label transfer between the APOGEE and GALAH surveys. Lux is a powerful new framework for the analysis of large-scale spectroscopic survey data. Its ability to handle uncertainties while maintaining high precision makes it particularly valuable for stellar survey label inference and cross-survey analysis, and the flexible model structure allows for easy extension to other data types.

Keywords: Computational methods, Astronomy data modeling, Astronomy data analysis, Spectroscopy
Expected Impact of Rubin Observatory LSST on NEO Follow-up. We simulate and analyze the contribution of the Rubin Observatory Legacy Survey of Space and Time (LSST) to the rate of discovery of near-Earth-object (NEO) candidates, their submission rates to the NEO Confirmation page (NEOCP), and the resulting demands on the worldwide NEO follow-up observation system. We find that, when using current NEOCP listing criteria, Rubin will typically contribute ∼129 new objects to the NEOCP each night in the first year, an increase of relative to present day. Only 8.3% of the objects listed for follow-up will be NEOs, with the primary contaminant being a background of yet undiscovered, faint, main-belt asteroids. We consider follow-up prioritisation strategies to lessen the impact on the NEO follow-up system. We develop an algorithm that predicts (with 68% accuracy) whether Rubin itself will self recover any given tracklet; external follow-up of such candidates can be deprioritized. With this algorithm enabled, the follow-up list would be reduced to 64 NEO candidates per night (with ∼8.4% purity). We propose additional criteria based on trailing, apparent magnitude, and ecliptic latitude to further prioritize follow-up. We hope observation planners and brokers will adopt some of these open-source algorithms, enabling the follow-up community to effectively keep up with the NEOCP in the early years of LSST.

Keywords: Near-Earth objects, Small Solar System bodies, Asteroids, Surveys, Solar system, Main belt asteroids
Logos-Zoe: A Contact Binary Triple System in the Trans-Neptunian Belt. The trans-Neptunian object (58534) 1997 CQ29 (a.k.a. Logos) is a resolved wide binary in the dynamically Cold Classical population. With Hubble Space Telescope resolved observations where the primary Logos is well separated from its secondary Zoe it can be established that Logos has a time-variable brightness. Logos' brightness varied by several tenths of a magnitude over a short timescale of hours while the brightness variability of Zoe was on a longer timescale. New unresolved ground-based observations obtained with the Lowell Discovery Telescope and the Magellan-Baade telescope confirm at least one highly variable component in this system. With our ground-based observations and photometric constraints from space-based observations, we suggest that the primary Logos is likely a close/contact binary whose rotational period is 17.43 ± 0.06 hr for a lightcurve amplitude of 0.70 ± 0.07 mag, while Zoe is potentially a (very) slow rotator with an unknown shape. Using the Candela software, we model the Logos-Zoe system and predict its upcoming mutual events season using rotational, physical, and mutual orbit parameters derived in this work or already published. Zoe's shape and rotational period are still uncertain, so we consider various options to better understand Zoe. The upcoming mutual event season for Logos-Zoe starts in 2026 and will last for four years with up to two events per year. Observations of these mutual events will allow us to significantly improve the physical and rotational properties of both Logos and Zoe.

Keywords: Light curves, Classical Kuiper belt objects, Trans-Neptunian objects
SYNTHPOP: A New Framework for Synthetic Milky Way Population Generation. We present SYNTHPOP, a new open source, modular population synthesis Galactic modeling software to simulate catalogs of Milky Way stars along any sightline outward from the Sun. Motivated by a lack of flexibility in existing Galactic models, SYNTHPOP is coded entirely in python, can be run standalone or as an imported module, and is configured by json files that allow different model components to be switched out as desired. We describe the modular code structure, how the population generation process runs, and how to use the code. We also present model validation testing and known inaccuracies and present an example of the code use, comparing Gaia data and the Gaia Universe Model Snapshot to a SYNTHPOP implementation. The code is available now via GitHub with ReadTheDocs documentation and can be installed via pip.

Keywords: Stellar populations, Astronomical models, Milky Way Galaxy
The Dynamic Inner Disk of a Planet-forming Star. Planets are a natural byproduct of the stellar formation process, resulting from local aggregations of material within the disks surrounding young stars. Whereas signatures of gas-giant planets at large orbital separations have been observed and successfully modeled within protoplanetary disks, the formation pathways of planets within their host star's future habitable zones remain poorly understood. Analyzing multiple nights of observations conducted over a short, 2 month span with the MIRC-X and PIONIER instruments at the CHARA Array and VLTI, respectively, we uncover a highly active environment at the inner-edge of the planet formation region in the disk of HD 163296. In particular, we localize and track the motion of a disk feature near the dust-sublimation radius with a pattern speed of less than half the local Keplerian velocity, providing a potential glimpse at the planet formation process in action within the inner astronomical unit. We emphasize that this result is at the edge of what is currently possible with available optical interferometric techniques and behooves confirmation with a temporally dense followup observing campaign.

Keywords: Optical interferometry, Herbig Ae/Be stars, Protoplanetary disks, Planet formation
OGLE-2016-BLG-1195Lb: A Sub-Neptune Beyond the Snow Line of an M-dwarf Confirmed by Keck Adaptive Optics. We present the analysis of high-resolution follow-up observations of OGLE-2016-BLG-1195 using Laser Guide Star Adaptive Optics with Keck, seven years after the event's peak. We resolve the lens, measuring its flux and the relative source-lens proper motion, thus finding the system to be a Mp = 10.08 ± 1.18M⊕ planet orbiting an M-dwarf, ML = 0.62 ± 0.05M⊙, beyond the snow line, with a projected separation of r⊥ = 2.24 ± 0.21 au at DL = 7.45 ± 0.55 kpc. Our results are consistent with the discovery paper, which reports values with 1σ uncertainties based on a single mass–distance constraint from finite source effects. However, both the discovery paper and our follow-up results disagree with the analysis of a different group that also present the planetary signal detection. The latter utilizes Spitzer photometry to measure a parallax signal claiming the system is an Earth-mass planet orbiting an ultracool dwarf. Their parallax signal though is improbable since it suggests a lens star in the disk moving perpendicular to or counter to the Galactic disk rotation. Moreover, microlensing parallaxes can be impacted by systematic errors in the photometry. Therefore, we reanalyze the Spitzer photometry using a pixel level decorrelation model to detrend detector systematics. We find that we cannot confidently recover the same detrended light curve that is likely dominated by systematic errors in the photometric data. The results of this paper act as a cautionary tale that a careful understanding of detector systematics and how they influence astrophysical constraints is crucial.

Keywords: Gravitational microlensing, Exoplanet detection methods, Adaptive optics
Simulating Continuum-based Redshift Measurement in the Roman's High Latitude Spectroscopic Survey. We investigate the capability of the Nancy Grace Roman Space Telescope's (Roman) Wide-Field Instrument G150 slitless grism to detect red, quiescent galaxies based on the current reference survey. We simulate dispersed images for Roman reference High-Latitude Spectroscopic Survey (HLSS) and analyze two-dimensional spectroscopic data using the grism Redshift and Line Analysis (Grizli) software. This study focus on assessing Roman grism's capability for continuum-level redshift measurement for a redshift range of 0.5 ≤ z ≤ 2.5. The redshift recovery is assessed by setting three requirements of:  σz=z−ztrue1+z≤0.01 , signal-to-noise ratio≥ 5 and the presence of a single dominant peak in redshift likelihood function. We find that, for quiescent galaxies, the reference HLSS can reach a redshift recovery completeness of ≥50% for F158 magnitude brighter than 20.2 mag. We also explore how different survey parameters, such as exposure time and the number of exposures, influence the accuracy and completeness of redshift recovery, providing insights that could optimize future survey strategies and enhance the scientific yield of the Roman in cosmological research.

Keywords: Cosmology, Galaxy spectroscopy, Astronomical simulations
Far-ultraviolet Flares and Variability of the Young M Dwarf AU Mic: A Nondetection of Planet C in Transit at Lyα. Atmospheric escape's potential to shape the exoplanet population motivates detailed observations of systems actively undergoing escape. AU Mic is a young and active M dwarf hosting two close-in transiting sub- to Neptune-sized planets. Atmospheric escape was previously detected on the inner planet b, with radially blown neutral hydrogen producing ∼30% blueshifted absorption in Lyα. We obtained one Hubble Space Telescope/Space Telescope Imaging Spectrograph transit of the outer planet c, to search for the planet's escaping atmosphere in transmission at Lyα and compare with AU Mic b. We detected six short-duration flares in Si IV and C IV, of which only one corresponded to a Lyα flare. We identified longer-duration stellar variability at the tens of percent level for lines less sensitive to stellar activity, including O I, C II and Lyα, which inhibits detection of an exosphere. We do not report absorption associated with an exosphere containing neutral hydrogen or any metals detectable in the far-ultraviolet, and discuss the implications of the nondetection. This work highlights the importance of (1) careful consideration of stellar variability in atmospheric escape observations, and (2) the dual influence of photoionization and stellar wind when interpreting and modeling atmospheric escape.

Keywords: Exoplanet atmospheric composition , Exoplanet atmospheres, Exoplanet atmospheric evolution
Asteroseismology with PBjam 2.0: Measuring Dipole Mode Frequencies in Coupling Regimes from Main-sequence to Low-luminosity Red Giant Stars. PBjam is an open-source software package for measuring mode frequencies of solar-like oscillators. These frequencies help constrain stellar evolution models to precisely estimate masses, radii, and ages of stars. The overall aim of PBjam is to simplify this process to the point where it may be done by nonexperts or performed on thousands of stars with minimal interaction. The initial release of PBjam was restricted to only identifying modes of ℓ = 0 and ℓ = 2, since these are the simplest to treat consistently across different stellar evolutionary stages. Here we introduce a new set of three separate models, which lets PBjam automatically identify ℓ = 1 modes in stars that experience varying degrees of coupling between p- and g-modes. These include a simple asymptotic relation for p-modes that can be applied to main-sequence stars, a matrix formalism aimed at treating frequency dependent coupling in subgiants, and a uniform coupling model that is suitable for red giants. These models follow the Bayesian methodology established in the first release of PBjam, where a large set of previous observations is used to construct a nonparametric prior probability density for the new set of model parameters. This extension allows PBjam to build a more complete description of the power due to oscillations across a wider range of evolutionary stages.

Keywords: Open source software, Asteroseismology, Astronomy data analysis
The Resonant Remains of Broken Chains from Major and Minor Mergers. TESS and Kepler have revealed that practically all close-in sub-Neptunes form in mean-motion resonant chains, most of which unravel on timescales of 100 Myr. Using N-body integrations, we study how planetary collisions from destabilized resonant chains produce the orbital period distribution observed among mature systems, focusing on the resonant fine structures remaining post-instability. In their natal chains, planets near first-order resonances have period ratios just wide of perfect commensurability, driven there by disk migration and eccentricity damping. Sufficiently large resonant libration amplitudes are needed to trigger instability. Ensuing collisions between planets ("major mergers") erode but do not eliminate resonant pairs; surviving pairs show up as narrow "peaks" just wide of commensurability in the histogram of neighboring-planet period ratios. Merger products exhibit a broad range of period ratios, filling the space between relatively closely separated resonances such as the 5:4, 4:3, and 3:2, but failing to bridge the wider gap between the 3:2 and 2:1—a "trough" thus manifests just short of the 2:1 resonance, as observed. Major mergers generate debris that undergoes "minor mergers" with planets, in many cases further widening resonant pairs. With all this dynamical activity, free eccentricities of resonant pairs, and by extension the phases of their transit timing variations, are readily excited. Nonresonant planets, being merger products, are predicted to have higher masses than resonant planets, as observed. At the same time, a small fraction of mergers produce a high-mass tail in the resonant population, also observed.

Keywords: Exoplanet dynamics, N-body simulations
Detection of an Explosive Outflow in G34.26+0.15. This paper reports on the detection of a likely explosive outflow in the high-mass star-forming complex G34.26+0.15, adding to the small number (six) of explosive outflows detected so far. ALMA CO(2–1) and SiO(5–4) archival observations reveal multiple outflow streamers from G34.26+0.15, which correlate well with H2 jets identified from Spitzer-IRAC 4.5 μm and [4.5]/[3.6] flux ratio maps. These nearly linear outflow streamers originate from a common center within an ultracompact H II region located in the complex. The velocity spread of the outflow streamers ranges from 0 to 120 km s‑1. The radial velocities of these streamers follow the Hubble–Lemaître velocity law, indicating an explosive nature. From the CO emission, the total outflow mass, momentum, and outflow energy are estimated to be ∼264 M⊙, 4.3 × 103 M⊙ km s‑1, and 1048 erg, respectively. The event triggering the outflow may have occurred about 19,000 yr ago and could also be responsible for powering the expanding UC H II region, given the similar dynamical ages and positional coincidence of the UC H II region with the origin of the outflow. The magnetic field lines in the region associated with G34.26+0.15 also appear to align with the direction of the outflow streamers and jets, possibly being dragged by the explosive outflow.

Keywords: Submillimeter astronomy, Star formation, Interstellar dynamics