Sazuna/UAT_keywords huggingface dataset:
The Rotational Spectrum of 1-cyanocyclopentene and Its Search towards TMC-1. The astronomical detection of CN-functionalized ring molecules in TMC-1 has opened a new and unexplored area in space-based aromatic organic chemistry. The rotational spectrum of 1-cyano-cyclopentene (1-CNCPE) has been investigated using a combination of low- and high-resolution microwave spectroscopy techniques under jet-cooled and room temperature conditions. A Stark-modulated low-resolution spectrum revealed a clear a-type R-branch band structure, indicative of a single dominant rotamer with prolate character. High-resolution spectra recorded with broadband (CP-FTMW) and narrowband (MB-FTMW) techniques exhibited a doubling of transitions, attributed to tunneling between two ring-puckering vibrational substates, denoted 0+ and 0−. In addition, the millimeter-wave spectrum in the 329─394 GHz region has also been analyzed. Due to strong coupling between these levels, the spectral analysis required a Hamiltonian including Coriolis interaction terms within the reduced axis system formalism. This approach enabled the successful assignment and fitting of over 1244 rotational transitions, including hyperfine structure from the 14N nucleus and weak b- and c-type lines. The final spectroscopic parameters provide a reliable basis for astrophysical searches, and partition functions are reported at standard temperatures. We have searched for this species toward TMC-1 using the data of the QUIJOTE line survey. Only a 3σ upper limit to the column density of 3 × 1010 cm−2 has been obtained. Using the available spectroscopic data, we also searched for the two axial and equatorial conformers of 3-cyanocyclopentene, establishing an upper limit similar to that of 1-CNCPE.

Keywords: Molecular spectroscopy, Millimeter-wave spectroscopy, Microwave spectroscopy, Interstellar medium, Radio astronomy
Probing Accretion Disk Winds of Stratified Nature with Fe XXVI Doublet in Black Hole X-Ray Binaries. Powerful ionized accretion disk winds are often observed during episodic outbursts in Galactic black hole transients. Among those X-ray absorbers, Fe XXVI doublet structure (Lyα1+Lyα2 with ∼20 eV apart) has a unique potential to better probe the underlying physical nature of the wind, i.e., density and kinematics. We demonstrate, based on a physically motivated magnetic disk wind scenario of a stratified structure in density and velocity, that the doublet line profile can be effectively utilized as a diagnostic to measure wind density and associated velocity dispersion (due to thermal turbulence and/or dynamical shear motion in winds). Our simulated doublet spectra with postprocess radiative transfer calculations indicate that the profile can be (1) broad with a single peak for higher-velocity dispersion (≳5000 km s−1), (2) a standard shape with 1:2 canonical flux ratio for moderate dispersion (∼1000─5000 km s−1), or (3) double-peaked with its flux ratio approaching 1:1 for lower-velocity dispersion (≲1000 km s−1) in an optically thin regime, allowing various line shapes. Such a diversity in doublet profiles is indeed unambiguously seen in recent observations with XRISM/Resolve at microcalorimeter resolution. We show that some implications inferred from the model will help constrain the local wind physics where Fe XXVI is predominantly produced in a large-scale, stratified wind.

Keywords: Accretion, Black hole physics, Photoionization, High energy astrophysics, Plasma astrophysics, Stellar mass black holes, Atomic spectroscopy, Active galactic nuclei
The Filament Rift: ΛCDM's Structural Challenge against Observation. This study presents the first extended comparison of cosmic filaments identified in Sloan Digital Sky Survey (SDSS) DR10 observations (z &lt; 0.05) and the IllustrisTNG300-1 ΛCDM simulation (z = 0), utilizing the novel GrAviPaSt filament-finder method. The analyses are performed on both macro and microfilaments, each characterized by their length, thickness, and contrast in mass density. In addition to total sample comparisons, two subcategories of microfilaments, linking pairs of galaxy groups (GG) and linking pairs of galaxy clusters (CC), are introduced to further analyze discrepancies between the ΛCDM model and observation. While ΛCDM produces extended macrofilaments, such structures are largely absent from SDSS, and where present, they exhibit higher densities than their simulated counterparts. Microfilaments also show notable density discrepancies: at fixed length and thickness, observational filaments are significantly denser than those in the simulation. Employing radial density profiles reveal that microfilaments in the ΛCDM simulation exhibit higher contrasts in mass density relative to the background compared to their observational counterparts. Notably, CC-type microfilaments displayed enhanced density contrasts over GG types in the simulation, while observational data showed the opposite trend. Furthermore, SDSS galaxies in both GG and CC microfilaments exhibit lower specific star formation rates and older stellar populations, while TNG300-1 microfilaments host more actively star-forming galaxies within the intermediate stellar mass range. These results reveal persistent discrepancies between observational data and the ΛCDM reconstruction of cosmic filaments, pointing to possible tensions in our current understanding of large-scale structures and their environmental effects on galaxy evolution.

Keywords: Galaxy environments, Observational cosmology, Cosmic web, Large-scale structure of the universe
Dissecting the Mass Quenching in TNG50: Galaxy Size Determines the Quenching Mode. The diminishing of star formation is accompanied by size differentiating, as quiescent galaxies are more compact than star-forming galaxies (SFGs) at fixed stellar mass. In order to understand how galaxy quenching is related to galaxy sizes, we performed a demographic study of 46 massive quiescent central galaxies with stellar mass from 1010.5 to 1011 M⊙ in the TNG50 simulation. We found that, in addition to the triggering active galactic nucleus (AGN) feedback, galaxy size is also a major determinant of the quenching process, as small and compact galaxies are immediately quenched by the kinetic AGN feedback, while galaxies with large sizes are still active until strangulated by the cutoff of new gas replenishment. Further spatially resolved inspection reveals that this short and intense kinetic AGN feedback can only suppress the star formation within 1─2 kpc, resulting in this size-dependent effect of quenching. We also identify a long-term effect of a few Gyr timescale that the gas inflow rate is progressively suppressed after triggering kinetic feedback, which appears to effectively quench large galaxies entirely. We conclude that kinetic AGN feedback has two key roles in quenching: a short-term, intense effect that quenches the central 2 kpc region and a long-term effect that suppresses the gas inflow rate and further quenches the entire galaxy.

Keywords: Hydrodynamical simulations, Galaxy quenching, Galaxy evolution
First X-Ray and Radio Polarimetry of the Neutron Star Low-mass X-Ray Binary GX 17+2. We report the first polarimetric results of the neutron star low-mass X-ray binary Z-source GX 17+2 using the Imaging X-ray Polarimetry Explorer (IXPE) and the Very Large Array (VLA). We find that the X-ray source was polarized at PD = 1.9% ± 0.3% (1σ errors) with a polarization angle of PA = 11° ± 4° (1σ errors). Simultaneous Nuclear Spectroscopic Telescope Array observations show that the source was in the normal branch during our IXPE observations. The X-ray spectropolarimetry results suggest a source geometry comprising an accretion disk component, a Comptonization component, and a reflection component. The VLA radio polarization study shows a PD = 2.2% ± 0.2% with a Faraday-corrected intrinsic polarization angle of 1° ± 5°, which is an indication of the jet axis. Thus, we find the estimated X-ray PA from the source is consistent with the radio PA. We discuss the accretion geometry of the Z-source in light of our X-ray spectropolarimetry and radio findings.

Keywords: Neutron stars, Accretion, X-ray binary stars, Low-mass x-ray binary stars, Polarimetry
Investigating the Influence of Radiative Feedback in the Bright-rimmed Cloud 44. Radiative feedback from massive stars plays a central role in the evolution of molecular clouds and the interstellar medium. This paper presents a multiwavelength analysis of the bright-rimmed cloud (BRC) 44, which is located at the periphery of the H II region Sh2-145 and is excited by the massive stars in the region. We use a combination of archival and newly obtained infrared data, along with new optical observations, to provide a census of young stellar objects (YSOs) in the region and to estimate stellar parameters such as age, mass, etc. The spatial distribution of YSOs visible in the optical wavelength suggests that they are distributed in separate clumps compared to the embedded YSOs and are relatively older. Near-infrared spectroscopy of four YSOs in this region using the TANSPEC mounted on the 3.6 m Devasthal Optical Telescope confirms their youth. From spectral energy distribution fitting, most of the embedded YSO candidates are in their early stage of evolution, with the majority of them in their class II and some in their class I stage. The relative proper motions of the YSOs with respect to the ionizing source are indicative of the rocket effect in the BRC. The 12CO, 13CO, and C18O observations with the Purple Mountain Observatory are used to trace the distribution of molecular gas in the region. A comparison of the cold molecular gas distribution with simple analytical model calculations shows that the cloud is in the compression stage, and massive stars may be influencing the formation of young embedded stars in the BRC region due to radiative feedback.

Keywords: Star forming regions, Young star clusters, Star formation, Low mass stars, H II regions
Probing the Origin of X-Ray Flares in the Low-hard State of GRS 1915+105 Using AstroSat and NuSTAR. We performed a detailed time-resolved spectral study of GRS 1915+105 during its low-flux rebrightening phase using the broadband capabilities of AstroSat and NuSTAR in 2019 May─June. The AstroSat light curves revealed erratic X-ray flares with count rates rising by a factor of ∼5. Flares with simultaneous LAXPC and SXT coverage were segmented and fitted using two degenerate but physically motivated spectral models: a reflection-dominated model (hereafter model A) and an absorption-dominated model (hereafter model B). In model A, the inner disk radius (Rin) shows a broken power-law dependence on flux, indicating rapid inward motion of the disk at higher flux levels. In contrast, model B shows variable column density in the range of 1023─1024 cm−2, displaying a strong anticorrelation with flux. Both models exhibit significant variation in the ionization parameter between low- and high-flux segments. The total unabsorbed luminosity in the 0.7─30 keV energy range ranged from 6.64 × 1036 to 6.33 × 1038 erg s−1. Across both models, several spectral parameters exhibited step-function-like behavior around flux thresholds of 5─10 × 10−9 erg cm−2 s−1, indicating multiple spectral regimes. The disk flux contribution, more evident in model B, increased with total flux, supporting an intrinsic origin for the variability. These findings point to a complex interplay between intrinsic disk emission, structured winds, and variable local absorption in driving the flare activity.

Keywords: Accretion, X-ray binary stars, Stellar accretion disks
Photometric Redshift Forecast for the 7-Dimensional Sky Survey. We investigate the expected accuracy of redshifts that can be obtained using low-resolution spectroscopic (medium-band) data from the 7-Dimensional Sky Survey (7DS). By leveraging 40 densely sampled filters with widths of FWHM = 25 nm, we create 7DS mock catalogs and estimate the redshift accuracy for three 7DS main surveys: the Wide-field Time-Domain Survey (WTS), the Intensive Monitoring Survey, and the Reference Imaging Survey. Using photometric redshifts calculated from EAZY, we find that the 5 yr WTS provides reliable photometric redshifts with a normalized median absolute deviation (σNMAD) ranging from 0.003 to 0.007 and a catastrophic failure fraction (η) from 0.8% to 8.1% at 19 ≤ m625 &lt; 22. The spectral resolution R ∼ 50 of the medium-band data set effectively captures the 4000 Å break and various emission lines. We also explore the synergy with data obtained from the Pan-STARRS1, VIKING, and SPHEREx surveys. Combining the SPHEREx all-sky data with WTS significantly improves the accuracy of photometric redshift estimates, achieving η = 0.4% and σNMAD = 0.004 for fainter sources at higher redshifts. The additional near-IR information provided by SPHEREx and VIKING plays an essential role in resolving degeneracies between low and high redshifts. We also observe color excesses by subtracting adjacent broadband data, which improves the confinement of photometric redshifts and aids in the detection of strong emission line galaxies.

Keywords: Medium band photometry, Sky surveys, Redshift surveys
Unveiling Stellar Feedback and Cloud Structure in the ρ Ophiuchi-A Region Using ALMA and JWST: Discovery of Substellar Cores, C<SUP>18</SUP>O Striations, and Protostellar Outflows. In clustered star-forming regions, stellar feedback, such as H II regions/photon-dominated regions (PDRs), and protostellar jets/outflows, shapes cloud structures and influences star formation. Using high-resolution Atacama Large Millimeter/submillimeter Array millimeter and JWST infrared data, we analyze the cloud structure and the impact of stellar feedback in the nearest dense cluster-forming region Ophiuchi (Oph) A. All six known Class 0/I and two of the six flat-spectrum/Class II objects are detected in the 1.3 mm dust continuum. Additionally, we newly detected seven substellar cores, three of which show compact near-infrared emission, suggesting they are young substellar objects. The remaining cores, with masses of ∼10−2 M⊙ and mean densities of ∼108 cm−3, are likely gravitationally bound. They appear connected by faint CO finger-like structures extending from the triple Class 0 system Very Large Array (VLA) 1623-2417 Aa+Ab+B, suggesting they may have been ejected from the close binary VLA 1623 Aa+Ab. 12CO and near-infrared data reveal multiple protostellar outflows. From the comparison, we identified several new outflows/jets and shocked structures associated with the GSS 30 large bipolar bubble. Strong 12CO emission traces the eastern edge of the Oph A ridge, forming part of the expanding H II/PDR bubble driven by the nearby Herbig Be star S1. The northern ridge appears "blown out," with warm gas flowing toward GSS 30, injecting additional turbulent momentum. Several C18O striations in the S1 bubble align with magnetic fields, and position─velocity diagrams show wave-like patterns, possibly reflecting magnetohydrodynamic waves. Stellar feedback significantly influences Oph A's cloud structure.

Keywords: Brown dwarfs, Stellar jets, Molecular clouds, Photodissociation regions, Star formation, Interstellar medium, Protostars
Reconstructing the Anisotropic Ultralong Wavelength Spectra Using a Single Antenna on Lunar Orbit. The ultralong wavelength sky (ν ≲ 30 MHz) is still largely unexplored, as the electromagnetic wave is heavily absorbed and distorted by the ionosphere on Earth. The farside of the Moon, either in lunar orbit or on lunar surface, is the ideal site for observations in this band, and the upcoming Moon-based interferometers will obtain multifrequency high-resolution sky maps. Making use of the lunar occultation of the sky and the anisotropy of antenna primary beam response, we propose a novel method to reconstruct the ultralong wavelength spectral shape in multiple directions in the sky using only one antenna on lunar orbit. We apply the method to one antenna on one of the nine daughter satellites of the proposed Discovering the Sky at Longest wavelength project. Using simulated observation data between 1 and 30 MHz from one dipole antenna, we find that the spectra for different regions on the sky can be reconstructed very well, and the free─free absorption feature in each region can be derived from the reconstructed spectra. This work demonstrates the feasibility of reconstructing the unbiased anisotropic spectra using very limited instrumentation on a lunar orbit, with mature technologies already in place. It extends the application of such kind of satellite in revealing the distribution of free electrons in the Galactic interstellar medium from the distribution of absorption features in the ultralong wavelength sky.

Keywords: Brightness temperature, Interstellar absorption, Interstellar medium, Radio continuum emission, Spectral index, Radio astronomy
Validating Open Cluster Candidates with Photometric Bayesian Evidence. The thousands of open cluster (OC) candidates identified by the Gaia mission are significantly contaminated by false positives from field star fluctuations, posing a major validation challenge. Based on the Mixture Model for OCs, we present a Bayesian framework for validating OC candidates in the color─magnitude diagram. The method compares the Bayesian evidence of two competing models: a single stellar population with field contamination versus a pure field population. Their ratio, the Bayes factor (BF), quantifies the statistical support for cluster existence. Tests on confirmed clusters and random fields show that a threshold of BF &gt; 100 effectively distinguishes genuine clusters from chance field overdensities. This approach provides a robust, quantitative tool for OC validation and catalog refinement. The framework is extendable to multidimensional validation, incorporating kinematics, and is broadly applicable to other resolved stellar systems, including candidate moving groups, stellar streams, and dwarf satellites.

Keywords: Bayesian statistics, Hertzsprung Russell diagram, Open star clusters, Bayes factor, Mixture model
Morphological Regimes of Rotating Moist Convection. Moist convection is a physical process in planetary atmospheres where the latent heat released by condensation acts as a buoyancy source that can enhance or even trigger an overturning convective instability. Since the saturation temperature often decreases with height, condensation releases latent heat preferentially in regions of upflow. Due to this inhomogeneous heat source, moist convection may be more sensitive to changes in flow morphology, such as those induced by rotation, than dry Rayleigh─Bénard convection. In rotating systems, like Jupiter's weather layer, the effects of rotation on moist convection may be significant. In order to study the effects of rotation on flows driven by latent heat release, we present a suite of numerical simulations that solve the Rainy─Bénard equations. We identify three morphological regimes: a cellular regime and a plume regime broadly analogous to those found in rotating Rayleigh─Bénard convection, and a novel funnel regime found at Rossby numbers appropriate for Jupiter's weather layer that lacks a clear analog within the regimes exhibited by dry convection. We measure energy fluxes through the system and report rotational scalings of the Reynolds and moist Nusselt numbers. We find that moist static energy transport, as measured by a moist Nusselt number, is significantly enhanced in the funnel regime without a corresponding enhancement in Reynolds number, indicating that this funnel regime produces structures with more favorable correlations between the temperature and vertical velocity.

Keywords: Atmospheric dynamics, Planetary atmospheres, Astrophysical fluid dynamics
Survival of the Accretion Disk in LMC Recurrent Nova 1968-12a: UV─X-Ray Case Study of the 2024 Eruption. We report on UV and X-ray observations of the 2024 eruption of the recurrent nova LMCN 1968-12a, a rapidly recurring extragalactic system with a ∼4.3 yr recurrence period and a massive white dwarf. The eruption was discovered on 2024 August 1.8 by Swift, and subsequently monitored using AstroSat's UVIT and Soft X-Ray Telescope, along with Swift's UVOT and X-Ray Telescope. The multiwavelength light curves reveal a rapid UV─optical decline, followed by a plateau phase exhibiting 1.26 day modulations consistent with the orbital period. The supersoft X-ray emission, which emerged by day 5, exhibited a double peak, suggesting variable obscuration that could be due to an inhomogeneous nova ejecta or due to a nova superremnant along the line of sight. Time-resolved X-ray spectroscopy shows a blackbody component with T ≍ 106 K. The spectral energy distributions obtained concurrently in the UV, peaking at T ≍ 20,000 K and with a source radius ∼2─3 R⊙, are inconsistent with emission from the secondary star or nova photosphere alone. Instead, the UV emission is attributed to an irradiated accretion disk that survived the eruption. The persistent UV plateau and its temperature suggest that the accretion disk was not completely disrupted and resumed activity within days, consistent with recent findings in other rapidly recurring novae such as U Sco and M31N 2008-12a.

Keywords: X-ray astronomy, Accretion, Binary stars, Large Magellanic Cloud, Novae, Ultraviolet astronomy, Recurrent novae, Eclipsing binary stars, Cataclysmic variable stars
The Southern Photometrical Local Universe Survey (S-PLUS): Searching for Metal-poor Dwarf Galaxies. The metal content of a galaxy's interstellar medium (ISM) reflects the interplay between different evolutionary processes, such as feedback from massive stars and the accretion of gas from the intergalactic medium. Despite the expected abundance of low-luminosity galaxies, the low-mass and low-metallicity regime remains relatively understudied. Since the properties of their ISM resemble those of early galaxies, identifying such objects in the Local Universe is crucial to understanding the early stages of galaxy evolution. We used the DR3 catalog of the Southern Photometric Local Universe Survey (S-PLUS) to select low-metallicity dwarf galaxy candidates based on color selection criteria typical of metal-poor, star-forming, low-mass systems. The final sample contains approximately 50 candidates. Spectral energy distribution fitting of the 12 S-PLUS bands reveals that ∼60% of the candidates are best fit by models with low stellar metallicities. We obtained long-slit observations with the Gemini Multi-Object Spectrograph to follow up on a pilot sample and confirm whether these galaxies have low metallicities. We find oxygen abundances in the range 7.28 &lt; 12 + log(O/H) &lt; 7.82 (4%─13% of the solar value), confirming their metal-poor nature. Most targets are outliers in the mass─metallicity relation, i.e., they display a low metal content relative to their observed stellar masses. In some cases, perturbed optical morphologies might give evidence of dwarf-dwarf interactions or mergers. These results suggest that the low oxygen abundances may be associated with an external event causing the accretion of metal-poor gas, which dilutes the oxygen abundance in these systems.

Keywords: Dwarf galaxies, Star formation, Galaxy evolution, Interstellar medium, Metallicity