Sazuna/UAT_keywords huggingface dataset:
Post-outburst and Nebular Phase Spectra of the Fe II-type Nova V378 Serpentis. Infrared and optical spectra are presented for the nova V378 Serpentis from 28 and 103 days after maximum light. The earlier spectrum, from the post-outburst phase, displays strong lines of N I, moderate lines of C I, and the signature Fe II lines. He I features are just emerging and the MWIR region is dominated by H I emission. The later spectrum captures a moment in the nebular phase through which many Fe II novae pass characterized by the strong forbidden lines [N II] 0.5755 μm and [O II] 0.7319, 0.7329 μm. Modeling with the photoionization code CLOUDY indicates these lines arise throughout much of the emission line gas despite densities exceeding 1 × 108 cm‑3. Other results from the modeling include estimates for the temperature of the nova remnant (4.0–5.0 × 104 K) and ejected mass (2.2 × 10‑5 M ☉).

Keywords: Novae, Classical novae
No Missing Flare in OJ 287. The quasar OJ 287 has shown large flares since 1888, following a pattern that arises in a supermassive black hole binary when the secondary hits the accretion disk of the primary, and releases a hot bubble of gas at every disk crossing. A complete mathematical solution of the flare sequence produced a list of future flares, the latest happening in the summer of 2022. Here I look into the origin of the idea that the lack of seeing the 2022 flare is a theoretical problem. During the summer OJ 287 cannot be observed by ground-based optical telescopes. In a paper published in 2021, ahead of the 2022 observing campaign, this was clearly stated. The often repeated claim that there is a "missing flare problem," is a misunderstanding, as no detection was possible with the current instrumentation.

Keywords: BL Lacertae objects
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. IX. HD 27295 (53 Tau). The line of Hg II located at 5677.10 Å and the commonly used line at 3983.93 Å are not detected in UVES and ELODIE spectra of 53 Tau. The synthesis of selected lines of twenty chemical elements yields new abundance determinations for this sharp-lined star. Helium, carbon, oxygen, magnesium, aluminum, silicon, sulfur, scandium and iron are underabundant. Sodium has a solar abundance while phosphorus, calcium, titanium, chromium, manganese, strontium, ytrium, zirconium, xenon and barium are overabundant. The abundance excesses/deficiencies agree with previous determinations for aluminum, chromium, manganese, iron and strontium.

Keywords: Chemically peculiar stars, Manganese stars
FluxCT V2.0: Updates to a Web Tool Identifying Contaminating Flux in Space Telescope Data. We present FluxCT V2.0, an updated web tool for identifying contaminating flux in Kepler and TESS target pixel files. FluxCT V2.0 focuses on enhancing functionality, user experience, and data processing capabilities. We resolved existing issues to allow for an extended user base, removed known bugs, and extended the tool to any TESS pixel file, allowing the user to search any TESS point object. A batch code for TESS is now available on the companion GitHub. Additional output parameters, such as amplitude dilution and a magnitude cut, have been added to the tool, allowing users more freedom to analyze the possible effects of target sources.

Keywords: Stellar astronomy, Educational software, Astronomy software
Catalog of Cataclysmic Variables Around the Period-bounce: New Systems. A large portion of cataclysmic variables (CVs), between 40% and 80%, are predicted to be in the last stage of their evolution, becoming period-bouncers. This sub-class of CVs is characterized by having gone through a reversal in the evolution of their orbital periods as well as having a late-type donor. The large predicted population of period-bouncers has, however, not been observed so far. We have led an effort to reveal the missing population of period-bouncers though the use the X-ray survey eROSITA, which has increased the population of period-bouncers by 63% through the use of eROSITA. This study has established eROSITA as a promising path for the identification of the new members of this underrepresented sub-class of CVs.

Keywords: X-ray binary stars, X-ray surveys, Compact objects, Cataclysmic variable stars, Catalogs
A New Limit on the Graviton Mass from the Convergence Scale of the CMB Dipole. The clustering dipole in the 2MASS galaxy survey converges on a scale of ∼400 Mpc to the local peculiar velocity inferred from the Cosmic–Microwave–Background dipole. I show that this limits the graviton mass in Yukawa theories of gravity to less than 5 × 10‑32 eV. The new limit is 2.5 × 108 times tighter than the latest constraint from gravitational waves detected by the LIGO–Virgo–KAGRA collaboration and comparable to a previous limit from weak lensing.

Keywords: Gravitation
Symmetry in Hyper Suprime-Cam Galaxy Spin Directions. We perform a Bayesian analysis of anisotropy in binary galaxy spin directions in the Hyper-Suprime Cam Data Release 3 catalog, in response to a recent claim that it exhibits a dipole. We find no significant evidence for anisotropy, or for a direction-independent spin probability that differs from 0.5. These results are unchanged allowing for a quadrupole or simply searching for a fixed anisotropy between any two hemispheres, and the Bayes factor indicates decisive evidence for the isotropic model. Our principled method contrasts with the statistic employed by Shamir, which lacks a strong theoretical foundation. Our code is available at ✎.

Keywords: Astrostatistics, Bayesian statistics, Galaxies, Large-scale structure of the universe
qCMOS Detectors and the Case of Hypothetical Primordial Black Holes in the Solar System, near Earth Objects, Transients, and Other High-cadence Observations. Recent progress with CMOS detector development has opened new parameter space for high cadence time resolved imaging of transients and fast proper motion solar system objects. Using computer simulations for a ground-based 1.23 m telescope, this research note illustrates the gain of a new generation of fast readout low noise qCMOS sensors over CCDs and makes the case for high precision monitoring of asteroid orbits that can potentially shed light on the hypothetical existence of low mass primordial black holes, as well as for other applications requiring high speed imaging.

Keywords: Astronomical instrumentation
Confirmation of Recurrent Activity of Main-Belt Comet 456P/PANSTARRS (P/2021 L4). We report observations from the Magellan Baade Telescope and Lowell Discovery Telescope on UT 2024 October 3 and 26, respectively, confirming for the first time that active asteroid 456P/PANSTARRS is recurrently active (exhibiting a short anti-solar tail on both dates, following previous observations of activity in 2021 when it was discovered), indicating that its activity is likely driven by the sublimation of volatile ice, leading us to consider it a main-belt comet (MBC). We also report observations from the Gemini South Observatory on UT 2023 June 15 in which the object appears inactive, where we measure an absolute magnitude of  HV=(17.5±0.1)  mag for the nucleus (assuming GV = 0.15), corresponding to an effective nucleus radius of  rn=(1.0±0.2)  km (assuming an albedo of  pV=0.05) . 456P is now the 14th MBC for which recurrent activity has been observationally confirmed.

Keywords: Main-belt comets, Comet nuclei, Main belt asteroids, Comet dust tails, Comets, Comet volatiles
Discovery of a Unique Close Quasar–DSFG Pair Linked by a [C II] Bridge at z = 5.63. We report the discovery of a unique quasar-dusty star-forming galaxy (DSFG) system at z = 5.63, consisting of the bright quasar J1133+1603 (MUV = ‑ 27.42) and its compact, dust-obscured companion, J1133c. ALMA observations reveal a prominent [C II] bridge connecting the quasar and DSFG, indicating ongoing interaction at a projected separation of 1 8 (∼10 proper kpc). J1133c exhibits unusually bright and broad [C II] emission (L[C II] &gt; 1043 erg s ‑1, FWHM &gt; 500 km s‑1), with a [C II] luminosity five times that of the quasar, suggesting intense star formation or potential active galactic nucleus activity. The inferred star formation rate from [C II] is approximately 103M⊙ yr ‑1. The remarkable properties of this pair strongly suggest that galaxy interactions may simultaneously trigger both starburst and quasar activity, driving rapid evolution in the early universe.

Keywords: Quasars, High-redshift galaxies, Quasar-galaxy pairs
Multiple Periods in the Dwarf Nova GZ Cancri. TESS light curves of the SU UMa type dwarf nova GZ Cnc are analyzed. They reveal positive superhumps which persist until long after a superoutburst, variations at the orbital period restricted to outbursts, and transient negative superhumps. But none of these variations are seen simultaneously.

Keywords: Close binary stars, Cataclysmic variable stars, Dwarf novae, SU Ursae Majoris stars
Resolution Dependence of Cloud–Wind Simulations. Using a set of wind-tunnel simulations, we investigate the effect that numerical resolution has on cloud evolution and acceleration. We also consider the role of wind speed in both the subsonic and supersonic regimes, using adiabatic simulations with wind speeds of 100 km s‑1 and 1000 km s‑1, respectively. For each setup, we explore five numerical resolutions. We find that the fate of the cloud is significantly affected by the resolution, but the trend is surprisingly non-monotonic. In the subsonic case, we find that a resolution of 16 cells per cloud radius is a turning point in the cloud evolution. In the supersonic case the trend is more monotonic, consistent with the difference in timescales for which ram pressure acceleration dominates over mixing in the early acceleration.

Keywords: Galactic winds, Astrophysical fluid dynamics, Interstellar clouds, Circumgalactic medium
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. X. HD 221507 (β Scl). The weak line of Hg II located at 5677.10 Å is clearly detected as a 3% absorption feature in a FEROS and a UVES spectrum of the HgMn star HD 221507. In both spectra, the line has a filled-in core which might suggest stratification or weak emission. The synthesis of this Hg II feature yields a mercury excess, about +5.70 dex, for the FEROS spectrum which is about half of the +6.00 dex excess derived from the Hg II line at 3983.93 Å. In the UVES spectrum, the 5677.10 Å feature needs a larger excess of about +6.00 dex compatible with that derived from the 3983.93 Å line. A monitoring of the 5677.10 Å line should be carried out to address the variability of this line over the rotational period. No emission lines could be found in the red part of the spectra.

Keywords: Mercury-manganese stars, Chemically peculiar stars
Uchida's Theory of Magnetohydrodynamic Wave Refraction in an Inhomogeneous Medium: Testing the Theory with In Situ Measurements. Uchida's paper describes a theory of MHD wave propagation in an inhomogeneous medium. In theory, waves encountering spatial structures (such as active regions, coronal holes, and coronal streamers) should be refracted/reflected. In the solar corona, MHD waves are predicted to refract away from (or into) a structure, if the Alfvén speed VA increases (decreases) as the wave enters the structure. However, testing Uchida's theory in the corona requires that local densities ni and field strengths B (required to calculate VA) must be estimated indirectly. This limits significantly the reliability of testing Uchida's theory in the corona. I suggest that, to better test the theory, a different medium should be explored, specifically, one where VA can be precisely evaluated in situ. The solar wind is such a medium. A recent data set allows testing Uchida's theory over a broad range of times (~2 solar cycles) and radial locations (~2.5–5.4 au).

Keywords: Space plasmas, Magnetohydrodynamics, Solar coronal waves, Alfven waves
Detection of 19 lt-yr Long Bipolar Jets from Interacting Binary KX And. Bipolar jets with an apparent length of 20' ejected from KX And have been discovered in the first data release of the Northern Sky Narrowband Survey. KX And is a well-studied interacting binary with mass transfer through Roche lobe overflow at a distance of about 760 pc. However, the faint jets, which are visible in Hα light, have been overlooked in the past. With a known inclination of i ≈ 50° of the binary system, this leads to a true length of the jets of about 19 lt-yr (5.8 pc) in each direction.

Keywords: Stellar-interstellar interactions, Stellar jets, Interacting binary stars, Stellar mass loss, Emission nebulae, Interstellar medium, H II regions
The Impact of AGN Jet Speed on the Lyα Forest Flux Power Spectrum. The Lyα forest has received attention recently as a constraint for galactic feedback. In particular, different active galactic nucleus (AGN) feedback models have been shown to have varying effects on the Lyα forest. Some show minimal effect, while others have shown dramatic effects that may be observable given current data. Out of the various Lyα forest statistics, the 1D transmitted flux power spectrum (P1D) has shown the most potential in its ability to distinguish between feedback models. In this work we analyze the effects that AGN jets in the Simba simulation have on the Lyα forest P1D. We specifically explore how changing the maximum speed of the jets impacts the predicted P1D across a wide range of redshifts (0.1 &lt; z &lt; 2). We find that the impact of changing the jet speed on the P1D is most dramatic at lower redshifts (z &lt; 1) and k ≳ 2 × 10‑2.

Keywords: Cosmology, Supermassive black holes, Lyman alpha forest, Intergalactic gas, Active galactic nuclei, Intergalactic medium, Extragalactic astronomy
Examining the Rotation of the Planet-hosting M Dwarf GJ 3942. Based on radial velocities, EXORAP photometry, and activity indicators, the HArps-n red Dwarf Exoplanet Survey (HADES) team reported a 16.3 days rotation period for the M dwarf GJ 3942. However, an estimate of the magnitude-squared coherence between the HADES RV and Hα time series has significant peaks at frequencies 1/16 day‑1 and 1/32 day‑1. We turn to TESS photometry to test the hypothesis that the true rotation period is 32 days with 16 days harmonic. Although the average TESS periodogram has peaks at harmonics of 1/16 day‑1, the harmonic sequence is not fully resolved according to the Rayleigh criterion. The TESS observations suggest a 1/16 day‑1 rotation frequency and a 1/32 day‑1 subharmonic, though resolution makes the TESS rotation detection ambiguous.

Keywords: Lomb-Scargle periodogram, Stellar activity, Period search , Radial velocity, Stellar rotation, Time series analysis
Tentative Blazar Candidate EP240709A Associated with 4FGL J0031.5‑5648: NICER and Archival Multiwavelength Observations. We report on follow-up observations of the recently discovered transient by the Einstein Probe, EP240709A, with the Neutron star Interior Composition Explorer. We also incorporated archival multiwavelength survey data from the Neil Gehrels Swift Observatory (X-ray), Gaia (optical), the Fermi Gamma-ray Space Telescope (gamma-ray), and the Wide-field Infrared Survey Explorer (infrared) to distinguish between blazars and stellar systems. We suggest that EP240709A is likely an active blazar.

Keywords: Blazars, Active galactic nuclei
Two Intriguing Transits of HIP 23309 Observed by TESS. We present two distinct dips in the Transiting Exoplanet Survey Satellite light curves for HIP 23309, a young, active M0 dwarf, which has been previously identified as a potential exoplanet host candidate. We characterize both dips, and archival radial velocity data from ESO's High Accuracy Radial velocity Planet Searcher spectrograph, providing limits on a potential companion. Currently, we are unable to confirm the existence of a companion, or if the transits are caused by stellar variability.

Keywords: Stellar photometry, Radial velocity, Transit photometry, M dwarf stars
Spectroscopic Analysis of CWISE J151044.74‑524923.5, A Wide L Dwarf Companion to the L 262-74 System. We present the spectroscopy of CWISE J151044.74‑524923.5, a wide low-mass companion to the nearby (~24.7 pc) L 262-74 system. Analyzing the near-infrared spectrum obtained with the TripleSpec4 spectrograph on the Southern Astrophysical Research Telescope, we confirm that it is a brown dwarf with unusually red colors. Although this redness can be characteristic of young, low-gravity brown dwarfs, we assess that this object is likely a field object being reddened by factors other than youth. We assign it a spectral type of L6 (pec). Finally, we highlight new TESS data that provide further evidence of the multiplicity of the central system.

Keywords: Multiple stars, Brown dwarfs, L dwarfs, Spectroscopy, Near infrared astronomy
Photometric Classification of Tidal Disruption Event Host Galaxies Using Machine Learning. Tidal Disruption Events (TDEs) are transient events observed when a star gets tidally destroyed by a supermassive black hole. TDEs prefer quiescent Balmer-strong (QBS) host galaxies, which have strong Balmer absorption and weak emission lines. Identifying these galaxies photometrically is difficult but important for TDE classification. This research provides a method of using photometric data to identify QBS galaxies by applying machine learning classifiers such as the Random Forest Classifier (RF) and the K-Neighbors Classifier (KN). The classifiers cumulatively identify 9548 likely QBS galaxies, with the RF achieving 75%–96% purity and 50% completeness and the KN achieving 60%–99% purity and 45% completeness for QBS galaxies below photometric redshifts of 0.3.

Keywords: Tidal disruption, Random Forests, Transient sources, Post-starburst galaxies
Reassessing Ocean Retention Rates: The Role of Ocean Formation Time Assumptions in Rocky Exoplanet Studies. In this work, we aim to model ocean and atmospheric mass loss in exoplanets with varying orbital parameters to assess the impact of simulation assumptions on conclusions on planetary habitability. In particular, we examine how altering the time at which a planet's ocean is assumed to form may affect long-term inferred ocean retention rates. To study this relationship, we used VPlanet, a modular code that has the ability to model water loss on exoplanets. Using a suite of VPlanet simulations, we found that the stellar age at which a planet is assumed to form its oceans has a noticeable effect on the computed planetary water loss over Gyr timescales. This suggests that future research on ocean loss in exoplanets should account for the variability in the timing of when planets are able to form oceans.

Keywords: Exoplanet evolution, Habitable planets
Spatially Resolved Stellar Populations of z = 3–6 Lyα-emitting Galaxies with CEERS JWST NIRCam Imaging. We conduct spatially resolved spectral energy distribution (SED) fitting of 46 spectroscopically confirmed Lyα emitting galaxies at 3.5 &lt; z &lt; 6.5 using JWST NIRCam imaging data from the Extended Groth Strip field. Using PIXEDFIT for resolved photometry and SED fitting, we derive radial trends of star formation rate (SFR), surface stellar mass density, specific SFR (sSFR), stellar age, dust attenuation (AV), and metallicity. Our analysis reveals that galaxies below the star-forming main sequence (SFMS) display lower central sSFR and older stellar ages compared to those on/above the SFMS, aligning with the picture of inside-out quenching scenario. These findings provide hints into the physical properties and the structural evolution of high-redshift Lyα emitters in the early universe.

Keywords: Early universe, Stellar populations, Star formation, Galaxy evolution, Lyman-alpha galaxies, Reionization
Reconstructing In-channel Processes from the Eberswalde Delta on Mars. Studying ancient fluvial landforms on Mars is essential for understanding the planet's climate history and can provide valuable insights into the intensity and duration of liquid water activity. This research used an Earth-based model to constrain local estimates of fluvial activity at the Eberswalde crater delta on Mars and sharpen our understanding of the sedimentary record with novel grain size and sediment flux calculations at this site. Remote sensing methods were used to reconstruct in-channel processes and estimate the delta formation by sediment transported in intermittent flows over ∼71,500 yr. Such sustained hydrological activity may have once provided habitable conditions at Eberswalde.

Keywords: Mars, Planetary surfaces, Planetary science, Remote sensing
The Temperature versus Orbital Period Relation of AM CVns: Insights from Their Donors. We studied the spectral energy distribution of 22 known AM CVns with orbital periods (Porb) larger than 35 minutes using multiwavelength public photometric data to estimate the effective temperature of the accreting white dwarf. We find an infrared (IR) excess in all systems when compared to a single blackbody, both when the disk should be extended and when it should be truncated by the accretor's magnetic field. This suggests a dominant contribution from the donor to the IR flux. When fitting two blackbodies, the temperature of the hot component decreases with Porb, as expected by evolutionary models. Temperatures for systems with 35 &lt; Porb &lt; 45 minutes are consistent with models. Systems with Porb ≳ 45 minutes have higher temperatures than expected. The second blackbody temperature does not correlate with Porb.

Keywords: Accretion, AM Canum Venaticorum stars, White dwarf stars, Infrared excess, Cataclysmic variable stars
The Foundations of Multi-line Molecular Cloud Population Synthesis. While galactic molecular clouds have been studied in great detail, the spatial resolution of current single-dish radio telescopes inhibits our ability to resolve individual molecular clouds in external galaxies. In this case, the line luminosity signal received is an average over a ≥100 pc diameter beam containing several molecular clouds. This leads us to an interesting question: If we point the telescope beam at a region of molecular clouds in a nearby galaxy, can we meaningfully decompose the unresolved signal we receive? In this work, we formulate theoretical methods of decomposing a galaxy line luminosity signal into its cloud population line luminosity components.

Keywords: Interstellar molecules, Radio astronomy, Molecular clouds
The Multimodal Universe: 100 TB of Machine Learning Ready Astronomical Data. We present the Multimodal Universe, a new framework collating over 100 TB of multimodal astronomical data for its first release, spanning images, spectra, time series, tabular and hyper-spectral data. This unified collection enables a wide variety of machine learning (ML) applications and research across astronomical domains. The dataset brings together observations from multiple surveys, facilities, and wavelength regimes, providing standardized access to diverse data types. By providing uniform access to this diverse data, the Multimodal Universe aims to accelerate the development of ML methods for observational astronomy that can work across the large differences in astronomical datasets. The framework is actively supported and is designed to be extended whilst enforcing minimal self consistent conventions making contributing data as simple and practical as possible.

Keywords: Astronomy databases, Astronomy data acquisition