Sazuna/UAT_keywords huggingface dataset:
Autonomous Detection of Mineral Phases in a Rock Sample Using a Space-prototype LIMS Instrument and Unsupervised Machine Learning. In situ mineralogical and chemical analyses of rock samples using a space-prototype laser ablation ionization mass spectrometer along with unsupervised machine learning are powerful tools for the study of surface samples on planetary bodies. This potential is demonstrated through the examination of a thin section of a terrestrial rock sample in the laboratory. Autonomous isolation of mineral phases within the acquired mass spectrometric data is achieved with two dimensionality reduction techniques: uniform manifold approximation and projection (UMAP) and density-preserving variation of UMAP (densMAP), and the density-based clustering algorithm Hierarchical Density-Based Spatial Clustering of Applications with Noise (HDBSCAN). Both densMAP and UMAP yield comparable outcomes, successfully isolating the major mineral phases fluorapatite, calcite, and forsterite in the studied rock sample. Notably, densMAP reveals additional insights into the composition of the sample through outlier detection, uncovering signals from the trace minerals pyrite, rutile, baddeleyite, and uranothorianite. Through a grid search, the stability of the methods over a broad model parameter space is confirmed, revealing a correlation between the level of data preprocessing and the resulting clustering quality. Consequently, these methods represent effective strategies for data reduction, highlighting their potential application on board spacecraft to obtain direct and quantitative information on the chemical composition and mineralogy of planetary surfaces and to optimize mission returns through the unsupervised selection of valuable data.

Keywords: Laser ablation, Time-of-flight mass spectrometry, Dimensionality reduction
The Extreme Activity in Comet Hale–Bopp (C/1995 O1): Investigations of Extensive Narrowband Photoelectric Photometry. Conventional narrowband photoelectric photometry of Comet Hale–Bopp (1995 O1) was obtained on 99 nights from mid-1995 to early-2000, yielding gas and dust production rates over an unprecedented range of time and distance. The appearance of Hale–Bopp (H-B) presented a prime opportunity for active comet studies, and its inherent brightness and orbital geometry allowed the characterization of its long-term activity. Throughout the apparition, H-B released, by far, more gas and dust than any other comet ever measured. As a very high dust-to-gas ratio object, dust production was successfully measured throughout the apparition, with the dust consistently slightly red in color. All five gas species including OH and NH were detected just inside of 5 au inbound, while C2 and C3 were detected to just past 5 au outbound, and CN was followed until nearly 7.7 au. Heliocentric distance dependencies ranged between ‑1.2 and ‑2.7 in log–log space, with the extremes magnified by the large extrapolations in Haser model parameters at large distances. H-B's enormous size and associated extremely high outgassing resulted in a much larger collisional zone, which in turn yielded outflow velocities more than 2× higher than ever previously measured at comparable distances. Even so, volatile composition remained within the "typical" classification, consistent with most Oort Cloud comets, and water production follows the expected curve based on a standard water vaporization model. However, seasonal effects provided evidence for inhomogeneities among the major source regions on the surface of the nucleus. Preliminary modeling of the nucleus and coma successfully matches this seasonal behavior.

Keywords: Long period comets, Comets, Comet volatiles , Comae
Spectral Fit Residuals as an Indicator to Increase Model Complexity. Spectral fitting of X-ray data usually involves minimizing statistics like the chi-square and the Cash statistic. Here we discuss their limitations and introduce two measures based on the cumulative sum (CuSum) of model residuals to evaluate whether model complexity could be increased: the percentage of bins exceeding a nominal threshold in a CuSum array (pctCuSum), and the excess area under the CuSum compared to the nominal (p area). We demonstrate their use with an application to a Chandra ACIS spectral fit.

Keywords: X-ray astronomy, Astrostatistics tools, Astronomy software
The Late-epoch, Intermediate Excitation Spectrum of the Nova V612 Scuti. Optical and optical/infrared spectra of V612 Scuti from three and four years after outburst show a nova that has sustained nuclear burning and slowly increased in excitation but has not reached the excitation levels exhibited by many novae. The emission lines range in excitation from the nebular lines (e.g., [S III], [O III]), up to the coronal lines [Ca VIII] and [Si VII]. Distinctive spectral features are particularly strong lines of [Fe VII] and several features of [Fe VI] that include rarely seen infrared lines. A line at 2.04 μm frequently identified with [Al IX] in other novae, is shown to be [Fe V] 2.0401 in V496 Scuti. An analysis with the photoionization code CLOUDY suggests that a largely matter-bounded emission line region is excited by a photosphere of temperature 2.6 × 105 K and luminosity 1 × 104 L ⊙.

Keywords: Classical novae
AI Can Identify Solar System Instability Billions of Years in Advance. Rare event schemes require an approximation of the probability of the rare event as a function of system state. Finding an appropriate reaction coordinate is typically the most challenging aspect of applying a rare event scheme. Here we develop an artificial intelligence (AI) based reaction coordinate that effectively predicts which of a limited number of simulations of the solar system will go unstable using a convolutional neural network classifier. The performance of the algorithm does not degrade significantly even 3.5 billion years before the instability. We overcome the class imbalance intrinsic to rare event problems using a combination of minority class oversampling, increased minority class weighting, and pulling multiple non-overlapping training sequences from simulations. Our success suggests that AI may provide a promising avenue for developing reaction coordinates without detailed theoretical knowledge of the system.

Keywords: Convolutional neural networks, Solar system, Planetary dynamics, Mercury (planet)
Detecting the Undetected: Overcoming Biases in Gravitational-wave Population Studies. In the flourishing field of gravitational-wave astronomy, accurately inferring binary black hole merger formation channels is paramount. The Bayesian hierarchical model selection analysis offers a promising methodology (see, e.g., "One Channel to Rule Them All"). However, recently, Cheng et al. highlighted a critical caveat: observed channels absent in known models can bias branching fraction estimates. In this research note, we introduce a test to detect missing channels in such analyses. Our findings show a commendable success rate in identifying these elusive channels. Yet, in scenarios where missing channels closely overlap with recognized ones, discerning the difference remains challenging.

Keywords: Stellar populations, Astronomy data analysis, Gravitational wave sources, Gravitational wave astronomy, Astronomical simulations, Stellar evolution
M31N 2013-10c: A Newly Identified Recurrent Nova in M31. The nova M31N 2023-11f (2023yoa) has been recently identified as the second eruption of a previously recognized nova, M31N 2013-10c, establishing the latter object as the 21st recurrent nova system thus far identified in M31. Here we present well sampled R-band lightcurves of both the 2013 and 2023 eruptions of this system. The photometric evolution of each eruption was quite similar as expected for the same progenitor system. The 2013 and 2023 eruptions each reached peak magnitudes just brighter than R ~ 16, with fits to the declining branches of the eruptions yielding times to decline by two magnitudes of t 2(R) = 5.5 ± 1.7 and t 2(R) = 3.4 ± 1.5 days, respectively. M31N 2013-10c has an absolute magnitude at peak, M  R  = - 8.8 ± 0.2, making it the most luminous known recurrent nova in M31.

Keywords: Andromeda Galaxy, Recurrent novae, Novae
GRB 230911A: The First Discovery of a Fermi GRB Optical Counterpart with the Gravitational-wave Optical Transient Observer (GOTO). We report on the detection of candidate optical counterpart GOTO23akf/AT2023shv to the GRB 230911A with the Gravitational-wave Optical Transient Observer (GOTO) instruments located at La Palma, Canary Islands, and Siding Spring Observatory, Australia. The Fermi Gamma-ray Burst Monitor, which finds gamma-ray bursts (GRBs) nearly every two days, detected GRB 230911A with a statistical uncertainty of 4.°1. However, the large (~10-100 deg2) localization areas mostly impede the rapid identification of an optical counterpart. GOTO facilities fully covered 90% localization area of the GRB 230911A. We proposed GOTO23akf as the optical afterglow of GRB 230911A, subsequently confirmed through Swift-X-Ray Telescope observations in which an uncatalogued X-ray source spatially coincident with the GOTO candidate was detected. This is the first optical afterglow discovery for a Fermi GRB with the newly expanded GOTO network.

Keywords: Optical observation, Gamma-ray bursts
AstroLLaMA-Chat: Scaling AstroLLaMA with Conversational and Diverse Datasets. We explore the potential of enhancing LLM performance in astronomy-focused question-answering through targeted, continual pre-training. By employing a compact 7B-parameter LLaMA-2 model and focusing exclusively on a curated set of astronomy corpora-comprising abstracts, introductions, and conclusions-we achieve notable improvements in specialized topic comprehension. While general LLMs like GPT-4 excel in broader question-answering scenarios due to superior reasoning capabilities, our findings suggest that continual pre-training with limited resources can still enhance model performance on specialized topics. Additionally, we present an extension of AstroLLaMA: the fine-tuning of the 7B LLaMA model on a domain-specific conversational data set, culminating in the release of the chat-enabled AstroLLaMA for community use. Comprehensive quantitative benchmarking is currently in progress and will be detailed in an upcoming full paper. The model, AstroLLaMA-Chat, is now available at https://huggingface.co/universeTBD, providing the first open-source conversational AI tool tailored for the astronomy community.

Keywords: Publicly available software, Astronomical instrumentation, Astronomy software
Galactic Bulge Hypervelocity (HVS) RR Lyrae Variable Stars and One High Galactic Latitude HVS HB Star. Six Galactic Bulge Hypervelocity (HVS) RR Lyrae stars and one high galactic latitude HVS Horizontal Branch (HB) star found from the ongoing search for HVS in the Gaia DR3 and SIMBAD data are presented. Some of these stars may be unbound and may be leaving the Galaxy. The source of the hyper velocities acquired by these stars may be the influence of the massive black hole at the center of our the Milky Way or other processes such as the dynamical interaction with other stars in the densely populated Galactic bulge.

Keywords: Hypervelocity stars
Prospects for Connections to the Outer Halo of the Milky Way with LSST. Over its ten-year mission, Rubin Observatory's Legacy Survey of Space and Time will gather enough time series data to identify variable stars much fainter than previously observed. This makes ideal for finding RR Lyrae stars and mapping previously unexplored regions of our Galaxy's stellar halo. This project creates several mock data sets from both simulations and known satellite properties to model what might be found. We use these to examine the prospects for making connections between stellar structures already known around the Galaxy (satellites, streams and shells) and newly discovered stars. Such connections could be used to place constraints on the mass distribution in the outer regions of the Galaxy's dark matter halo. Our results are encouraging, suggesting: that tens of percent of the known structures should have counterparts in the outer halo; and that several entirely new unbound structures could be discovered.

Keywords: Dark matter distribution, Stellar streams, Dwarf galaxies, RR Lyrae variable stars, Hierarchical cosmology, Milky Way Galaxy
Gnuastro: Visualizing the Full Dynamic Range in Color Images. Color plays a crucial role in the visualization, interpretation, and analysis of multi-wavelength astronomical images. However, generating color images that accurately represent the full dynamic range of astronomical sources is challenging. In response, Gnuastro v0.22 introduces the program astscript-color-faint-gray, which is extensively documented in the Gnuastro manual. It employs a nonlinear transformation to assign an 8-bit RGB (Red-Green-Blue) value to brighter pixels, while the fainter ones are shown in an inverse grayscale. This approach enables the simultaneous visualization of low surface brightness features within the same image. This research note is reproducible with Maneage, on the Git commit c206945.

Keywords: Open source software, Astronomy data visualization, Astronomy software, Low surface brightness galaxies
The Abundance Pattern of The A2.5V Star HD 176687 (ζ Sagitarii A) In A Triple System. The synthesis of high resolution high signal-to-noise ratio optical and IUE spectra of HD 176687 allows the determination of LTE abundances for carbon, nitrogen, oxygen, aluminum, silicon, strontium, yttrium and zirconium. Carbon, nitrogen, oxygen and silicon are found to be depleted by a factor of 0.50. Aluminum is overabundant by a factor of 2.0. Strontium is solar, yttium is overabundant by a factor of 6, zirconium has an upper limit of 1 solar. The comparison of the FUV spectral energy distribution of HD 176687 to those of standard stars confirms that its effective temperature must be about 8800 ± 200 K, slightly larger than that of the A3 V standard, α PsA.

Keywords: A stars
Detection of Tm II Lines in the Spectra of Two s-process Rich Stars. Thulium abundance is unknown in the atmospheres of low and medium-mass evolved stars. The reason is the weakness of lines and the crowded spectra. We examined the spectra of two late-type stars in a broad wavelength region to search for thulium lines. Thulium abundance was estimated in the atmospheres of barium star HD 204075 and post-asymptotic giant branch star HD 235858 for the first time, $\mathrm{log}\,\epsilon (\mathrm{Tm})\simeq 0.1$ and ≲1.3, respectively.

Keywords: High resolution spectroscopy, Post-asymptotic giant branch stars, Stellar abundances, Spectral line identification, Late-type giant stars, Barium stars, Stellar atmospheres
James Webb Space Telescope Spectra of Cold Brown Dwarfs are Well-reproduced by Phosphine-free, Diabatic, ATMO2020++ Models. James Webb Space Telescope (JWST) mid-infrared spectra of cold brown dwarfs (BDs) are becoming available. In Leggett &amp; Tremblin we demonstrated that an ATMO2020++ synthetic spectrum provided an excellent fit to the first published spectrum. Here we show that these models can reproduce the 1-14 μm spectra of BDs with a range of effective temperature: 350 ≤ T eff K ≤ 500. A grid of these models, which include disequilibrium chemistry and non-adiabatic pressure-temperature profiles, is available. In addition, a number of models without phosphine were calculated, as PH3 is absent in the JWST data. Two of the six BDs studied are particularly interesting; one appears to be a young low-mass BD, the other is best fit as a binary. More complete analyses will be possible with an extended model grid, and with additional JWST data. The ATMO2020++ models are recommended for analyses of all BD data.

Keywords: Brown dwarfs, Atmospheric dynamics, Infrared spectroscopy
Light Curve of HT Cassiopeiae. Photometric observations of the eclipsing dwarf nova HT Cas are presented in its quiescent state on 2022 October 20th for one complete orbital period. These data were taken with the RISE imager mounted on the Liverpool Telescope. The lcurve code was used to fit the light curve. System parameters were derived of mass ratio q = M 2/M 1 = 0.15 ± 0.01, angle of inclination i = 80.°98 ± 0.°18 and white dwarf radius of R 1 = 0.0128 ± 0.0003R ⊙. This gives solutions for the masses of the white dwarf and donor star of M 1 = 0.571 ± 0.017M ⊙ and M 2 = 0.088 ± 0.005M ⊙. The disk radius and bright spot radius with the best fit from the model were R disk = 0.51 ± 0.04a and R spot = 0.32 ± 0.02a. These are consistent with previous published observations.

Keywords: Eclipsing binary stars, Light curves, Cataclysmic variable stars, Binary stars
Evaluation of a Magnetic Field Inversion Method Using Only Stokes I. We compare a method for inferring the photospheric vector magnetic field using only spectroscopy to a conventional method based on polarimetry. The magnetic field strength B and inclination angle can be inferred from the Zeeman splitting using only Stokes I. We applied this method to a sunspot observed with the Vacuum Tower Telescope and compared the results to vector magnetograms from the Helioseismic and Magnetic Imager on the Solar Dynamics Observatory, which used a polarimetric inversion. The spectroscopic inversion tends to show higher values in B compared to the polarimetric data. In quiet regions the discrepancy in B was typically a factor of two. In the strong sunspot fields, the differences averaged ≈22%. These discrepancies are significant, but comparable to those typically found among magnetograms from different instruments. Our results support the use of the spectroscopic inversion technique to provide a fast and reasonable estimate of B.

Keywords: Spectropolarimetry, Sunspots, Atomic spectroscopy, Solar physics, Solar magnetic fields, Spectroscopy, Magnetogram
A Comparison of Star-formation Histories Derived from UniverseMachine and LEGA-C at 0.6 &lt; z &lt; 1. In this work, we compare star formation histories of massive (10.5 $\lt \,\mathrm{log}({M}_{* }/{M}_{\odot })\,\lt $ 12) galaxies in the UniverseMachine model to those measured from the Large Early Galaxy Astrophysics Census (LEGA-C) at 0.6 &lt; z &lt; 1. Following the LEGA-C study, we investigate how 50% (t 50) and 90% (t 90) formation timescales depend on total stellar mass. We find good agreement between the observed and model timescales for the star-forming population Δ t SF ≲ 1 Gyr across the full mass range. In contrast, the observed age-mass correlation is weaker for the quiescent population compared to UniverseMachine models (Δt  Q  ≲ 2 Gyr), especially at the high-mass end. This indicates continued star formation or additional processes in the most massive quiescent galaxies, a behavior not accounted for in the UniverseMachine model.

Keywords: Galaxy dark matter halos, Astronomy data modeling, Theoretical models, Surveys, Astronomy data analysis, Galaxy evolution, Extragalactic astronomy
NE2001p: A Native Python Implementation of the NE2001 Galactic Electron Density Model. The Galactic electron density model NE2001 describes the multicomponent ionized structure of the Milky Way interstellar medium. NE2001 forward models the dispersion and scattering of compact radio sources, including pulsars, fast radio bursts, active galactic nuclei, and masers, and the model is routinely used to predict the distances of radio sources lacking independent distance measures. Here we present the open-source package NE2001p, a fully Python implementation of NE2001. The model parameters are identical to NE2001 but the computational architecture is optimized for Python, yielding small (&lt;1%) numerical differences between NE2001p and the Fortran code. NE2001p can be used on the command-line and through Python scripts available on PyPI. Future package releases will include modular extensions aimed at providing short-term improvements to model accuracy, including a modified thick disk scale height and additional clumps and voids. This implementation of NE2001 is a springboard to a next-generation Galactic electron density model now in development.

Keywords: Galactic radio sources, Extragalactic radio sources, Interstellar scintillation, Interstellar plasma, Pulsars, Warm ionized medium, Distance indicators, Active galactic nuclei, Astrophysical masers, Interstellar medium, Hot ionized medium, Radio transient sources
Activity Discovered on Mars-Crossing Jupiter Family Comet 2018 OR by Citizen Scientists. We present the discovery of cometary activity on 2018 OR as part of our Active Asteroids project, a NASA Partner Program fueled by Zooniverse Citizen Scientists. Volunteers found 2018 OR with a long, diffuse tail in archival images from the Dark Energy Camera on the Blanco 4 m telescope at the Cerro Tololo Inter-American Observatory in Chile. Our team identified additional Canada-France-Hawaii-Telescope MegaCam and Zwicky Transient Facility archival data after classification by Citizen Scientists. Activity originating from 2018 OR and directed in the anti-solar and anti-velocity directions was visible in archival images between UT 2018 September 5-18. Our dynamical simulations indicate 2018 OR experiences close encounters with Jupiter over hundred-year timescales. The orbital period and dynamics suggest 2018 OR is a Jupiter Family Comet, and we recommend further observations from the community to reduce observational uncertainties and investigate activity patterns.

Keywords: Comet tails, Short period comets, Comet dynamics
Detection Sensitivities from the Anglo-Australian Planet Search. Our understanding of the occurrence rates and demographics of long-period planets depends critically on data from legacy radial-velocity surveys with the long-term sensitivity to Jupiter-like planets in Jupiter-like orbits. A recent paper presented such an analysis for giant planets (m sin i &gt; 0.3 M J) from the now-completed Anglo-Australian Planet Search. In this work, I deliver the detailed detection sensitivities for all 203 individual stars in that study, as a function of orbital periods from 100 to 6000 days. We present these data as a companion to Wittenmyer et al.

Keywords: Extrasolar gaseous planets, Exoplanets
The Once-canceled Habitable-zone Super-Earth Gliese 581d Might Indeed Exist!. Recent studies indicate that Gliese 581d, a proposed habitable zone (HZ) super-Earth planet, does not exist, as the respective data denote that the planet is an artifact of stellar activity. Here we report evidence to the contrary considering that those studies were based on inaccurate spectroscopic measurements of the stellar rotation period regarding the planet's inactive host star (dM3). Gliese 581d, if real, is of particular interest as it constitutes the first planet identified to be in a stellar HZ outside of the solar system based on studies in 2007. If confirmed as a true planet, at 20.5 lt-yr, it would also be one of the nearest potentially habitable super-Earths.

Keywords: M dwarf stars, Exoplanets, Super Earths, Stellar activity, Exoplanet astronomy, Exoplanet detection methods, Stellar rotation, Habitable zone, Astronomy data reduction
Bug Found in Gaia query_object Functions of Astroquery's Python Package. This research note addresses a bug in the Gaia functionality of the astroquery Python package. The bug, which results in sources in the Gaia catalog not being returned, affects the Gaia.query_object() and Gaia.query_object_async() functions. These rely on the deprecated ADQL BOX function if width or height are specified. These functions are used in published research and as such the bug could affect peer-reviewed results. We advise any researchers using these functions to instead use the Gaia.cone_search() counterparts to these functions or the Gaia.launch_job() functions. The Gaia helpdesk have been contacted and have confirmed the behavior and may update the astroquery documentation in the coming months.

Keywords: Software documentation, Gaia, Astronomy software