Sazuna/UAT_keywords huggingface dataset:
Photometric Monitoring of MCG–06-30-15. We describe photometric monitoring of the Seyfert 1 galaxy MCG–06-30-15 with the Las Cumbres Observatory network. Using the V filter, 496 images were collected between 2023 December and 2024 June from observatories in Chile, South Africa, and Australia. We created light curves of the active galactic nucleus continuum emission using aperture photometry and image subtraction methods. We find that the typical magnitude difference between the two light curves is ΔV ≈ 1.9 mag, indicating that the host galaxy contributes approximately 85% of the total flux through the photometric aperture. The amplitude of variation is significantly enhanced when the host galaxy is removed: ΔV = 0.1 mag from aperture photometry compared to ΔV = 0.5 mag with image subtraction. Future work will compare the continuum light curve with the broad emission-line flux variations to provide insight into the physical parameters of the broad-line region in MCG–06-30-15 and the mass of the central supermassive black hole.

Keywords: Reverberation mapping, Seyfert galaxies
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å. XVIII. HD 53929. The weak line of Hg II located at 5677.10 Å is not detected in ESPaDOnS spectra of the HgMn star HD 53929. The Hg II feature at 3983.93 Å commonly used to measure the abundance of mercury in HgMn star is present as a very weak feature. The low abundance excess of mercury partly explains why the intrinsically weaker transition at 5677.10 Å is not detected. Abundances of helium, magnesium, phosphorus, sulfur, titanium, chromium, manganese, iron are measured from the synthesis of the several spectral intervals. The new abundances derived here differ from previous determinations because different fundamental parameters, projected rotational velocity, lines and atomic data have been used in this work. Solar upper limits are found for the abundances of strontium, zirconium, yttrium and barium. Inspection of the recent Transiting Exoplanet Survey Satellite lightcurves of HD 53929 shows a complex pattern of variability which might combine rotational and pulsational variability.

Keywords: Chemically peculiar stars, Manganese stars
Disentangling Joint Light Curves Using Photocenter Shifts: A Case Study Using NEOWISE Data. The data collected by the Wide-field Infrared Survey Explorer (WISE) and its follow-up Near Earth Object (NEO) mission (NEOWISE) represent a treasure trove for variability studies. However, the angular resolution imposed by the primary mirror implies that close double stars are often unresolved. Then, variability of one or both stars leads to motion of the image centroid along the connecting line. Knowledge of the angular separation, derived from higher-resolution imaging which resolves both components, allows disentangling of the joint light curve into individual ones. This is illustrated by the case of SPICY 1474 which featured an outburst several years ago. Removal of the contribution of the nearby companion, which led to a dilution of the burst strength, revealed that it was ∼0.5 mag brighter than in the joint light curve. A comparison with light curves from unTimely suggests that utilizing the photocenter shift may lead to more reliable results.

Keywords: Sky surveys, Young stellar objects, Astrometry, Space telescopes, Optical double stars
Disentangling the Effects of Temperature, Clouds, and Gravity on K I Doublet in L Dwarfs. We investigate the effects of surface gravity, effective temperature, and cloudiness on the potassium doublet (K I) at 1.17 μm in brown dwarf spectra. Using pseudo-Voigt profiles to fit the K I doublet in Sonora Diamondback atmospheric model spectra, we find that gravity and cloudiness affect the spectra differently in mid to late-L dwarfs. The full-width at half-maximum (FWHM) is strongly correlated with surface gravity, while the maximum depth strongly correlates with cloudiness. This method allows us to separate the effects of clouds and surface gravity on the K I 1.17 μm doublet. We also find that the FWHM and maximum depth of the doublet can help to estimate the effective temperature and surface gravity in early to mid-L dwarfs.

Keywords: Astronomy data modeling, Brown dwarfs, L dwarfs, Spectral index, Stellar spectral lines
A Search for Calcium in the Atmosphere of Europa with Ground-based Telescope. Europa's tenuous atmosphere mainly consists of molecular oxygen, with traces of sodium, potassium, and other elements, potentially reflecting the composition of its surface and interior. While sodium- and magnesium-bearing hydrated salts have been suspected to exist on the surface, other materials like calcium-bearing salts dissolved in the subsurface ocean could also be present. Atmospheric emissions could originate from sputtering or sublimation processes, and potential water plume activity, possibly influenced by tidal interactions, could significantly contribute to the atmosphere. Additionally, the composition of the atmosphere and surface could be affected by neighboring moons, particularly Io. We searched for calcium emissions using the Multi-Spectral Imager of a 1.6 m Pirka telescope at Hokkaido University's Astronomical Observatory. Observations from 2021 September to 2023 October revealed suggestive emission lines attributed to calcium atoms. These suggestive emission lines originated from the trailing hemisphere, suggesting that sputtering is likely the dominant atmospheric source.

Keywords: Galilean satellites, Ground telescopes
Swift-XRT Observations and Upper Limits at Five LHAASO Galactic Sources. The detection of low-energy counterparts to gamma-ray sources is critical to understanding the nature of the astrophysical systems producing such high-energy emission. We report on Swift-XRT observations at five LHAASO gamma-ray sources with no known low-energy counterpart and scant previous X-ray observations. At four of the five LHAASO targets, we detect no significant X-ray point sources, while at 1LHAASO J1928+1813u we detect a single X-ray source that is likely related to X-ray emission from a local cool stellar system. These results suggest that many X-ray counterparts to LHAASO sources have X-ray flux below ≈10‑13 erg s‑1 cm‑2, or have diffuse X-ray emission not visible in brief observations.

Keywords: Gamma-ray sources, X-ray sources
Discovery of Photodissociation Region in Overlapping Galaxy Pair VV 191 with HST and JWST. We present a photodissociation region (PDR) found ∼17 kpc from the galaxy center in the outer disk of the foreground spiral galaxy of partially overlapping—occulting—galaxy pair VV 191 at z ∼ 0.05. Dust attenuation in foreground galaxy, VV 191b, is derived using backlighting by the superimposed background elliptical galaxy VV 191a. Imaging with the James Webb Space Telescope (JWST) and the Hubble Space Telescope span the wavelength range 0.3–4.5 μm at ∼100 pc scales resolution. We observe this PDR by isolating the 3.3 μm aromatic infrared band using the JWST F356W and F444W filters and analyzing the dust attenuation and reddening surrounding the PDR cavity. Results show a spiral-arm like dust cavity surrounding the PDR with visual evidence of 3.3 μm polycyclic aromatic hydrocarbon emission around the strong ultraviolet emission associated with O and B stars.

Keywords: Interstellar dust, Polycyclic aromatic hydrocarbons, Disk galaxies, Photodissociation regions, Interstellar medium
The Early Infrared Spectrum of the Fe II Nova V1310 Scorpii. V1310 Scorpii (Nova Scorpii 2010, No. 1) was an Fe II-type nova whose early spectral properties are broadly representative of the class. We present a 0.8–5.2 μm spectrum from 11 days after peak brightness that exhibit these properties. In addition to the emission lines of C I, N I, and O I, V1310 Sco also shows the well-known one and two micron Fe II lines as well as midwave infrared (MWIR) Fe II lines not previously reported in novae. The strongest of the MWIR Fe II lines all descend from the same term (c4P), a term that is different from those that produce the one and two micron Fe II features.

Keywords: Classical novae
Exploring Black Hole Accretion Through Multidimensional Simulations. Our ability to electromagnetically detect and characterize astrophysical black holes depends crucially on their accretion of gas. We used the Eulerian grid codes FLASH, Athena, and Athena++ to perform fluid dynamic simulations, studying black hole accretion. Our findings demonstrate that, in viscous conditions, all three codes produce similar accretion rates, while, in non-viscous conditions, Athena++ appears to generate much smaller accretion rates. Nevertheless, our results give insight on the purely numerical variability of black hole accretion.

Keywords: Accretion, Hydrodynamical simulations, Black holes, Astrophysical black holes
Magnetic Fields of Satellite Galaxies Stronger than Comparable Centrals in TNG100. Magnetic fields exist in and around galaxies, but the properties of these fields have not been fully explored due to the challenges inherent in observing and modeling them. In this Note, we explore the differences in magnetic field strength of central and satellite galaxies from the magnetohydrodynamic TNG100 simulation. We find that on average, magnetic fields in satellite galaxies are roughly an order of magnitude stronger than those of central galaxies with comparable masses. The difference is greater for satellites that have already approached within 1R200 of their host galaxies. These results indicate that magnetic fields in satellite galaxies are amplified by environmental processes as they fall into a host halo.

Keywords: Galaxy magnetic fields, Dwarf galaxies
WTP 21aaeuqd: NEOWISE Discovery and Keck Confirmation of a Heavily Reddened, Optically Missed Galactic Nova. Despite their long history, a complete inventory of Galactic novae has remained incomplete due to severe dust extinction. Recent ground-based near-infrared (NIR) as well as space-based mid-infrared (MIR) searches are providing a new window into discovering heavily obscured Galactic novae. Even with its slow cadence, archival photometric searches for large-amplitude, fast fading outbursts in the NEOWISE survey were previously used to identify Galactic nova candidates between 2014 and 2020. In this paper, we demonstrate the efficacy of the method with the discovery and NIR spectroscopy of WTP 21aaeuqd—a bright (peak W2 AB flux ≈10.5 mag), rapidly evolving (t2 ≈ 120 days) MIR Galactic outburst (at  ). The reduced spectrum exhibits broad (≈800 km s‑1) emission lines of H I and C I, confirming its classification as a missed Fe II nova. This result confirms that archival infrared photometric searches are an effective way to identify nova candidates missed in optical searches.

Keywords: Observational astronomy, White dwarf stars, Novae, Cataclysmic variable stars, Astronomy image processing
An S-band Search for Highly Scattered Young Pulsars Toward Low Galactic Latitude Fermi Sources. We searched 20 unidentified Fermi sources at low Galactic latitudes for highly scattered young pulsars in the Northern sky. We performed ∼2 hr observations of each source with the Green Bank Telescope using the S band receiver, choosing sources whose positional uncertainties in 4FGL-DR3 are well covered by the GBT Beam at 2 GHz. Systematic uncertainties due to source confusion have previously prevented efficient searches at these higher frequencies. We discovered no new young pulsars in this survey.

Keywords: Rotation powered pulsars, Radio pulsars
Line Intensity Mapping Prediction from the Cosmic Dawn (CoDa). III. Simulation for Hα from Galaxies and the Intergalactic Medium During the Epoch of Reionization. The evolution of large-scale structure, galaxies and the intergalactic medium (IGM) during the Epoch of Reionization can be probed by upcoming Line Intensity Mapping (LIM) experiments, which sample in redshift and direction without needing to resolve individual galaxies. We predict the intensity and sources of hydrogen Hα emission, dominated by radiative recombination following ionization by UV from the same massive stars that caused reionization, down to redshift 4.6, using the largest fully coupled, radiation-hydro simulation of galaxy formation and reionization to date, Cosmic Dawn (CoDa) III. We compute the mean intensity and VID versus redshift, including the relative contributions of galaxies and IGM. This will provide mock data to guide and interpret LIM experiments such as NASA's SPHEREx and proposed CoDa Intensity Mapper.

Keywords: Cosmology, Hydrodynamical simulations, Galaxy evolution, Intergalactic medium, Reionization, Line intensities
The Calm Before the Storm: The Impact of Radiative Cooling on Magnetic Field Amplification. Turbulent radiative mixing layers (TRMLs) may play a crucial role in driving multiphase gas formation in galactic outflows and the circumgalactic medium. Magnetic fields pervade these regions and can be amplified by shear-driven turbulence and cooling-induced compression. However, strong magnetic fields inhibit mixing. We present three-dimensional magnetohydrodynamic simulations of ∼transonic, TRMLs, beginning with a weak uniform magnetic field (10‑12 G). Adiabatic simulations show essentially no change in magnetic-field strength during the first Kelvin–Helmholtz time, as one would expect. In contrast, simulations with radiative cooling boost the magnetic-field strength by a factor of 3–10. Allowing cooling to molecular temperatures appears to promote a sustained enhancement of magnetic-field strength, which may be aided by turbulent mixing. Our work helps to disentangle the driving mechanisms of magnetic-field amplification in turbulent mixing layers, which impact the survival of cold gas clouds in galactic winds.

Keywords: Galactic winds, Magnetohydrodynamics, Radiative processes, Interstellar medium, Circumgalactic medium
Anomalous Cepheids in Crater II. Fifteen Anomalous Cepheid (ACeph) candidates were recently identified in the dwarf galaxy Crater II via an extended survey done with the Dark Energy Camera at the 4 m Blanco Telescope at Cerro Tololo Inter-American Observatory (CTIO). Using various Period–Luminosity relationships found in the literature, we anchor these candidates to the nearby RR-Lyrae stars' distances to confirm 14 of the candidates as not only being ACephs, but as confidently belonging to Crater II rather than the field within the line-of-sight.

Keywords: Dwarf irregular galaxies, Periodic variable stars, Anomalous Cepheid variable stars, Stellar populations, Dwarf galaxies, Galaxy stellar content, RR Lyrae variable stars, Variable stars
Determination of the Abundance of Mercury from the Hg II line at 5677.10 Å. XIX. HD 190229 (14 Sge). The weak line of Hg II located at 5677.10 Å is detected in ESPaDOnS spectra of the HgMn star 14 Sge as a feature absorbing about 2% of the continuum. The synthesis of this line yields a mercury abundance which agrees well with previous determinations. The synthesis of the S II doublet at 4524.68 and 4524.95 Å shows that sulfur is deficient in 14 Sge by a factor of about ‑0.82 dex. Abundances of magnesium, phosphorus, sulfur, titanium, chromium, manganese, iron and gallium are also measured from the synthesis of the several spectral intervals. The new abundances derived here differ slightly from previous determinations as a different projected rotational velocity, lines and atomic data have been used in this work.

Keywords: Mercury-manganese stars, Chemically peculiar stars
Precise Near-infrared Occultation of WASP-19b with FourStar on Magellan. We describe the setup and procedure to obtain precise near-infrared photometry with the FourStar imager on the 6.5 m Magellan Baade Telescope at Las Campanas Observatory, which enabled the recovery of a 2316 ± 170 ppm secondary occultation (13.5σ) in the Ks filter for the ultra hot-Jupiter WASP-19b. The unbinned residuals are ∼1400 ppm in 11.6 s and bin to 660 ppm in 1 minute bins or 180 ppm in 15 minutes bins.

Keywords: Hot Jupiters, Exoplanets, Occultation, Photometry, Near infrared astronomy
Photometric Classification of SNAD Supernovae. We selected 132 supernova (SN) candidates from the SNAD catalog, originally discovered in the Zwicky Transient Facility data releases using an anomaly detection pipeline. Their multi-band light curves were fitted with several SN templates to assign each object to a photometric class: Ia, Ib/c, IIP, IIL, or IIn.

Keywords: Supernovae, Transient detection, Time domain astronomy, Time series analysis
PLUME: Plasma in a Linear Uniform Magnetized Environment. Characterizing waves in collisionless or weakly collisional magnetized plasmas is an essential task for quantifying a wide variety of physical processes in space and astrophysical systems. The linearized Vlasov–Maxwell system of equations is typically an accurate model for such characterization, and many numerical methods for solving the Vlasov–Maxwell dispersion relation derived from those equations have been implemented. The Plasma in a Linear Uniform Magnetized Environment (PLUME) code follows the derivation of the linear Vlasov–Maxwell dispersion relation presented in Chapter 10 of T. H. Stix, and is built on an implementation first presented in E. Quataert. A simplified version of PLUME was described in K. G. Klein &amp; G. G. Howes, but improvements to the code in intervening years necessitate an updated description. In this note, we specify the dimensionless normalization of the code and other pertinent details of the PLUME dispersion relation solver. The code is publicly available for download (codebase: https://github.com/kgklein/PLUME).

Keywords: Space plasmas, Alfven waves, Plasma physics
Gaia's Faintest Stars. In the Brief History of Time Stephen Hawking was pessimistic about astronomers detecting primordial black holes (PBHs). He would not be the only distinguished scientist to underestimate the extraordinary power of new technology. In a related area Albert Einstein published the equations for microlensing, but wrote off their practicality. Perhaps they meant "during my lifetime." The amazing properties of PBHs, however, validate heroic efforts to detect them. If they exist, their niches in our current history of time include supplying dark matter (DM) to bind galaxies, offering a solution for the Hubble tension, and, as supermassive black holes, giving us quasars as far as the eye can see. This Research Note describes a search for PBHs in the Gaia archive. In spite of the high density of local DM, it was unsuccessful. Microlensing with the Rubin telescope is the tool at our disposal to open the asteroid window for PBH.

Keywords: Cosmology, Exoplanet astronomy, Primordial black holes
No Evidence of Anomalous Diffusion in Yukawa Crystals. Diffusion in Yukawa crystals is stochastic due to the thermally activated formation of vacancy-interstitial pairs, which have poor statistics in simulations. This makes it difficult to argue if Yukawa crystals exhibit normal diffusion, or if they could be subdiffusive or superdiffusive. To resolve this, we run a long molecular dynamics simulation of an idealized Yukawa crystal for a billion timesteps. We find no evidence of anomalous diffusion in the pure crystal, but also caution readers against overinterpretting this result as real crystals have complicated structures including grains and defects.

Keywords: Neutron stars, Stellar interiors, Computational methods, Plasma physics
Is the Metallicity-rotation Correlation in Stars Determined by Deep-seated or Near-surface Layers in the Convective Envelope?. Metal-poor stars generally rotate faster than metal-rich stars. Recent explanations for this correlation rely on use of a Rossby number evaluated in the deepest layers of the convection zone. Here, I hypothesize that the correlation can also be understood in terms of conditions in the near-surface layers of the convection zone. The advantage of the latter is that physical parameters are more reliably measurable than in the deep interior.

Keywords: Stellar convection envelopes, Stellar physics, Dwarf stars, Main sequence stars, Stellar rotation
Impacts of Rising Light Pollution on Pollinators and Indigenous Food Sovereignty. Rapid increases in ground-based light pollution in recent decades and the accompanying rise in night sky brightness (NSB) have wide-ranging impacts on astronomical observations, cultural sky traditions, and the health of human beings and living ecosystems. Rising NSB affects the seasonal cycles of plants and the migration of birds, insects and animals. Here we focus on the migratory paths and populations of pollinators, and implications for the food sovereignty of Indigenous communities. These increasingly documented trends need targeted light pollution policies, as well as public engagement. Although current measures of light pollution and NSB are likely underestimated, successfully implemented solutions exist for this urgent yet solvable environmental crisis of our time.

Keywords: Cultural astronomy, Interdisciplinary astronomy, Light pollution, Night sky brightness
Hidden Companions to Intermediate-mass Stars. Upgraded Multiplicity 5 → 6. XXVII. Discovery of a 1.45M<SUB>⊙</SUB>, 0.6 au Companion to Beta2 Tucanae C. Beta2 Tucanae (β2 Tuc) is a nearby a = 22 au visual binary (C+D) and one of the brighter members of the young Tucana–Horologium association. Here we report on a VLTI/GRAVITY interferometric observation which revealed that β2 Tuc is actually a rather compact triple system: the primary is itself a close binary (Ca+Cb) with a projected separation ρ = 13.56 mas ↔ 0.59 au and a K band flux ratio of 56.65%. We estimate isochrone masses MCa ≃ 2.0M⊙, MCb ≃ 1.45M⊙ and MD ≃ 1.45M⊙. Together with its wide (∼1200 au) companion β1 Tuc (itself a binary) and very wide (∼23,000 au) companion β3 Tuc, this makes the β Tuc system a sextuple. The compactness and rather low effective hierarchy of β2 Tuc   make it a particularly interesting system for triple dynamics and stability studies. *Based on observations collected at the European Southern Observatory, Chile, Program ID 112.25QQ.001.

Keywords: Optical interferometry, Multiple stars, A stars
The Sonora Substellar Atmosphere Models. V. A Correction to the Disequilibrium Abundance of CO<SUB>2</SUB> for Sonora Elf Owl. To aid the interpretation of observations of substellar atmospheres, S. Mukherjee et al. created the Sonora Elf Owl grid of model atmospheres, simulations that accounted for disequilibrium quench chemistry. However, Sonora Elf Owl did not accurately estimate CO2 quenching because the models quenched the gas with respect to the full atmosphere equilibrium, but CO2 should have instead been quenched with respect to the disequilibrium (i.e., quenched) abundance of CO. As a result, Sonora Elf Owl under-predicted the CO2 abundance by several order of magnitude in some instances, an amount that JWST is sensitive to. Here, we release version two of the Sonora Elf Owl grid which has corrected CO2 concentrations. Additionally, in version two we remove PH3 as a spectral contributor since our spectra consistently contained too much PH3 absorption. The new spectra can be found as an update to the original Zenodo postings.

Keywords: L dwarfs, Y dwarfs, T dwarfs
Collisional Fragmentation Support in TRACE. We present improved collision support for TRACE, a state-of-the-art hybrid integrator in REBOUND. TRACE now supports collisional fragmentation and can handle both removing and adding particles mid-timestep. We describe the back-end logic implemented for robust collision support, and compare TRACE's performance to other integrators including MERCURIUS on a large-N protoplanetary disk simulation with various collision prescriptions, a system which TRACE previously could not handle. TRACE matches the behavior of these integrators, while offering potentially vast speedups of over 70×. All updates described in this Note are available with the most recent public release of REBOUND.

Keywords: Collision physics, Exoplanet formation, N-body simulations