Sazuna/UAT_keywords huggingface dataset:
Recommendations for Teaching Introductory Astronomy Online during the Coronavirus Pandemic. Colleges and universities around the world were forced to move their classes online in 2020 March due to the coronavirus pandemic. Because of the rapid transition to remote teaching, instructors received limited professional development to teach online. As the pandemic continues, many classes continue to be offered online. Institutions are providing training in teaching online and designing courses beyond what was given in 2020 March, but it is unlikely to be the formal training given to those planning to teach an online class. In this note, I provide key recommendations to developing and teaching introductory astronomy online during this time of limited professional development. I also briefly describe my experience of teaching during the pandemic in the Spring 2020 term, which motivated me to compile these recommendations.

Keywords: Observational astronomy, Galactic and extragalactic astronomy, Exoplanet astronomy, Stellar astronomy, Astrobiology, Solar system astronomy
Optimizing Numerical Simulations of Colliding Galaxies. II. Comparing Simulations to Astronomical Observations. Our research focuses on determining the dynamical orbital parameters associated with galaxy collisions. We are accomplishing this by optimizing numerical models of galactic interactions with astronomical observations of colliding galaxies and measuring the uncertainty in the parameter space of these models. This paper will focus on how we compare our numerical models to observed colliding galaxies. We create gravitational n-body models that capture the tidal distortions from galaxy collisions. The final particle positions are then processed to create model images that have realistic intensity profiles and resolutions. We compare the model's output with the astronomical images to obtain an objective machine score that should reflect the fitness of the model. To test our scoring methods, we then compare our machine scores to the human-scores obtained from the citizen science project Galaxy Zoo: Mergers.

Keywords: Cosmology, Galaxy collisions, Galaxy interactions, Galaxy mergers, Astronomical simulations
Computational Insight into Diatomic Molecules as Probes to Measure the Variation of the Proton-to-electron Mass Ratio. Astrophysical molecular spectroscopy is an important means of searching for new physics through probing the variation of the proton-to-electron mass ratio, μ. New molecular probes could provide tighter constraints on the variation of μ and better direction for theories of new physics. Here we summarize our previous paper for astronomers, highlighting the importance of accurate estimates of peak molecular abundance and temperature as well as spectral resolution and sensitivity of telescopes in different regions of the electromagnetic spectrum. While none of the 11 astrophysical diatomic molecules we investigated showed enhanced sensitive rovibronic transitions at observable intensities for astrophysical environments, we have gained a better understanding of the factors that contribute to high sensitivities. From our results, CN, CP, SiN and SiC have shown the most promise of all astrophysical diatomic molecules for further investigation, with further work currently being done on CN.

Keywords: High resolution spectroscopy, Molecular spectroscopy, Spectroscopy, Galactic and extragalactic astronomy
Performing Point-spread Function Fitting with Photutils on Hubble Space Telescope Images. The low mass end of the Initial Mass Function (IMF) is a component of star formation that is not well understood. By analyzing Hubble Space Telescope (HST) images of star-forming regions, we aimed to provide data to constrain the shape of the low-mass IMF. We performed point-spread function (PSF) fitting using the Astropy Photutils package v0.6 on shallow HST Wide Field Camera 3 images taken in filters F110W, F139M, and F160W with the goal of identifying low mass stars and brown dwarfs. Residual images from our PSF fitting routine showed that fainter sources were effectively fit while fits to the brighter sources left residuals. Despite this, analysis confirmed that our PSF magnitudes are consistent with aperture magnitudes and mostly have smaller errors; 85%-100% of the flux was captured by the PSF fitting in most cases. PSF fitting of WFC3-IR images using Photutils shows promise for precise photometry.

Keywords: Initial mass function, Photometry
An HRD-like Diagram for Pre-main Sequence Stars. When Pre-Main Sequence stars have two spectral types, an earlier one measured in the optical and a later one in the IR, the hotter one implies a greater Hertzsprung-Russell Diagram (HRD) mass than the cooler one. The mass discrepancy may be removed by plotting the stars on a modified HRD showing log (Luminosity) versus log (surface gravity). Placing two Pre-Main Sequence stars in Taurus, BP Tau and T Tau N, on such a HRD-like diagram shows that the hotter effective temperature represents the stars' intrinsic parameter determined by their luminosity and radius and resolves the mass discrepancy in favor of the larger mass.

Keywords: Pre-main sequence stars
Similarities between the X-Ray Light Curves of the 2016 and 2020 Eruptions of the Recurrent Nova LMC 1968. The latest eruption of the recurrent nova LMC 1968 was extensively observed by Swift with its X-ray Telescope instrument. A comparison with the Swift data set from the 2016 eruption shows that the X-ray evolution was remarkably similar just as the evolution of the optical photometry and spectroscopy was similar during previously observed eruptions. The only difference is a surprising decrease in the recurrence time. LMC 1968 is only the second nova for which Swift has observed the entire X-ray evolution more than once. At 50 kpc, it is close enough to be extensively observed in its next eruption.

Keywords: X-ray transient sources, X-ray binary stars, Recurrent novae
A Speckle Interferometric Search for a Companion to the RR Lyrae Star UV Oct. We obtained high-resolution, diffraction limited imaging of the candidate binary RR Lyrae UV Oct using Gemini-South/Zorro. We detect no companions between 0"1 and 1"2, with a contrast of Δm ∼ 5 mag, placing a mass constraint for any possible main sequence companion of m &lt; 0.67M⊙.

Keywords: RR Lyrae variable stars, Speckle interferometry
The Surface Abundances of 17 Com B: A Test for Self-consistent Evolutionary Models. Elemental abundances are derived for 17 Com B for 16 elements. They reinforce the Am status of this star. We show that the measured abundances are properly reproduced by stellar models including atomic diffusion and a parametrized turbulent diffusion coefficient. This parameterization agrees with that used in previous studies of Am stars.

Keywords: Stellar evolutionary models, Chemically peculiar stars, Chemical abundances, Stellar evolution
Photometric and Spectroscopic Analysis of Eclipsing Binary NSVS 11868841. We present new photometric and spectroscopic data on the low-mass, eclipsing binary star NSVS 11868841. Light and velocity data are analyzed and modeled. Resulting best-fit models indicate a change in the orbital period. Our 2019 October observation of secondary eclipse occurs 0.01042 days prior to that predicted by the latest published ephemeris when assuming a circular orbit. Our spectroscopic data from 2009 and 2019 yield a consistent systemic velocity of -9.78 ± 1.3 km s-1 and a mass ratio of 0.928 ± 0.016, both of which are significantly different than previous studies. Orbital period changes have not been indicated in earlier works either.

Keywords: Binary stars, Low mass stars, Photometry, Variable stars, Eclipsing binary stars, Spectroscopy, Variable star period change, Eclipsing binary minima timing method
Comparison of Radioastronomical Estimates of the Coronal and Solar Wind Magnetic Field with Measurements from Parker Solar Probe. The Parker Solar Probe (PSP) spacecraft is measuring plasma properties of the solar wind to heliocentric distances as small as 0.125 au or 26.9 solar radii. One of the most important plasma parameters is the strength of the magnetic field. A variety of radioastronomical remote sensing measurements also provide information on the magnetic field, from the solar surface to heliocentric distances of about 10 solar radii. In this paper, we compare radioastronomical estimates from one technique, Faraday rotation of background radio sources, with the PSP measurements. The extrapolated radioastronomical values are in good agreement with the measurements at the first and second perihelion passages in 2018 and 2019. Future radio measurements could therefore complement PSP measurements as it approaches the ultimate perihelion of 9.8 solar radii.

Keywords: Solar magnetic fields, Solar wind, Solar corona
Improved ASCOM Dome Following. An improved algorithm for dome following for an altitude-azimuth telescope mount is presented, with a specific implementation in ASCOM.

Keywords: Observatories, Astronomical instrumentation, Domes, Astronomy software
Rotation Optimized Filter for Longevity (ROFL): Increasing the Lifetime of Swift/UVOT Simply. I demonstrate that a very simple and safe change to the planning software filter assignment algorithm for the Ultraviolet/Optical Telescope (UVOT) onboard the Neil Gehrels Swift Observatory can reduce the number of filter wheel rotations by &gt;10%, and its adoption is thus likely to significantly extend the usable lifetime of the UVOT instrument.

Keywords: Ultraviolet telescopes
Spectrotemporal Analysis of a Sample of Bursts from FRB 121102. FRB 121102 was the first Fast Radio Burst (FRB) that was shown to repeat. Since its discovery in 2012, more than two hundred bursts have been detected from the source. These bursts exhibit a diverse range of spectral and temporal characteristics and many questions about their origin and form remain unanswered. Here, we present a sample of radio bursts from FRB 121102 detected using the Lovell telescope at Jodrell Bank Observatory. We show four examples of bursts that show peculiar spectro-temporal characteristics and compare them with properties of bursts of FRB 121102 detected at other observatories. We report on a precursor burst that is separated by just 17 ms from the main burst, the shortest reported separation between two individual bursts to date. We also provide access to data for all the detections of FRB 121102 in this campaign.

Keywords: Radio bursts, Radio transient sources
The Flat Galactic Rotation Curves from First Principles: A Novel Logarithmic Potential Originating in Laplace's Equation. This note reports flat galactic rotation curves coinciding with observation and originating in Laplace's classical field equation. Dark matter, identified with a primordial fluid populating the entire universe, is represented by the homogeneous Klein-Gordon equation (KGE). The key element is the novel solution for the KGE discovered by the leading author in 1994, expressed as a permanent background ${ \mathcal B }$ -potential plus an entangled ${ \mathcal E }$ -potential where time and distance appear as a ratio. The ${ \mathcal B }$ -potential may be viewed as solution to a non-homogeneous Laplace equation, for which the general solution contains in addition to Newton's 1/r potential a new logarithmic Zwicky potential overlooked thus far. The ensuing 1/r-Zwicky force predicts the observed flat galatic rotation curves exhibiting the observed limiting speed at long distance.

Keywords: Galaxy rotation curves, Newtonian gravitation
The Ultraviolet Flux Variations of ρ Puppis as Recorded by IUE. The archival IUE spectra of the bright δ Scuti star ρ Puppis (HD 67523) reveal large flux variations from 2000 to 3000 Å over an 8 hr observing run. The time separating two successive flux maxima at 2900 Å is 3 hr and 19 minutes which compares well to the period of the radial fundamental mode. At 2900 Å, the flux at maximum is about 1.20 larger than at minimum which is consistent with a 260 K increase of the effective temperature between minimum and maximum. The optical brightness around 5400 Å as recorded by the Fine Error Sensor varied in phase with the ultraviolet flux, corresponding to a decrease in magnitude of -0.11 mag.

Keywords: Delta Scuti variable stars
Modeling the Quasiperiodic Radial Velocity Variations of γ Draconis. γ Draconis, a K5III star, showed radial velocity (RV) variations consistent with a 10.7 Jupiter mass planet from 2003 to 2011. After 2011, the periodic signal decayed, then reappeared with a phase shift. Hatzes et al. suggested that γ Dra's RV variations could come from oscillatory convective modes, but did not fit a mathematical model. Here we assess whether a quasi-periodic Gaussian process—appropriate when spots with finite lifetimes trace underlying periodicity—can explain the RVs. We find that a model with only one quasiperiodic signal is not adequate: we require a second component to fit the data. The best-fit model has quasi-periodic oscillations with P1 = 705 days and P2 = 15 days. The 705 day signal may be caused by magnetic activity. The 15 day period requires further investigation.

Keywords: Exoplanet detection methods, Bayesian statistics, Exoplanets, Stellar activity, Gaussian Processes regression, Radial velocity, Stellar rotation
Detection of a Disk Surrounding the Variably Accreting Young Star HBC722. We present new ALMA 233 GHz continuum observations of the FU Orionis Object HBC722. With these data we detect HBC722 at millimeter wavelengths for the first time, use this detection to calculate a circumstellar disk mass of 0.024 M⊙, and discuss implications for the burst triggering mechanism.

Keywords: Star formation, FU Orionis stars
The EXPRES Stellar-signals Project. I. Description of Data. The EXPRES Stellar-Signals Project is providing sets of high-fidelity, spectroscopic and photometric observations to enable direct comparisons of various approaches for disentangling stellar signals and true radial velocities (RVs). We will provide all EXPRES RVs, meta data, and activity indicators as well as high-precision photometric data from the Fairborn Automatic Photoelectric Telescopes (APTs) for HD 101501, HD 34411, HD 217014, and HD 10700. Intrinsic stellar variability and the resulting apparent RVs are widely believed to dominate the error budget for extremely precise radial-velocity (EPRV) measurements. Several new methods to disentangle photospheric velocities from Keplerian velocities are being developed throughout the EPRV community. In addition to releasing data sets for testing these methods, the EXPRES Stellar-Signals Project will publish a summary of the current state of the field circa 2020 to guide next steps toward mitigating photospheric velocities in EPRV data. More information can be found on http://exoplanets.astro.yale.edu/science/activity.php.

Keywords: Radial velocity, Stellar activity, Spectrometers, Planet hosting stars, Exoplanet detection methods
Detection of Coherent Pulsation Modes in the Strongly Magnetic Of?p Star NGC 1624-2 using TESS Observation. High-cadence Transiting Exoplanet Survey Satellite (TESS) observations are promising for studies of short-term pulsational variability in magnetic O stars, which usually have long rotation periods of the order of months or years. The Of?p star NGC 1624-2 is of special interest as it possesses the strongest magnetic field measured among O stars, together with a giant magnetosphere. We detect three significant low-frequency peaks in TESS 2 minute cadence data, probably corresponding to coherent g mode pulsations. At present, this is the only magnetic O star for which pulsational variability is detected.

Keywords: Space observatories, Magnetic stars, Variable stars, Stellar pulsations
All Known SN Ia Models Fail to Reproduce the Observed t<SUB>0</SUB>-M<SUB>N I56</SUB> Correlation. SNe Ia are likely the thermonuclear explosions of carbon-oxygen white-dwarf stars, but their progenitor systems remain elusive. A few theoretical scenarios for the progenitor systems have been suggested, which have been shown to agree with some observational properties of SNe Ia. However, several computational challenges prohibit a robust comparison to the observations. We focus on the observed ${t}_{0}\mbox{--}{M}_{{\rm{N}}{\rm{\small{I}}}56}$ relation, where t0 (the γ-rays' escape time from the ejecta) is positively correlated with ${M}_{{\rm{N}}{\rm{\small{I}}}56}$ (the synthesized 56Ni mass). Comparing to the ${t}_{0}\mbox{--}{M}_{{\rm{N}}{\rm{\small{I}}}56}$ relation bypasses the need for radiation transfer calculations, as the value of t0 can be directly inferred from the ejecta. We show that all known SNe Ia models fail to reproduce the observed ${t}_{0}\mbox{--}{M}_{{\rm{N}}{\rm{\small{I}}}56}$ correlation.

Keywords: Type Ia supernovae, Supernovae
Galaxies in the Zone of Avoidance with the Spitzer Space Telescope. In this work we describe 59 galaxies discovered in the talk-forum of the Milky Way Project (MWP) by volunteers of the project. The MWP is based on infrared images by the Spitzer Space Telescope and primarily probes the Zone of Avoidance for star-forming regions located in the Milky Way. The list of galaxies found here include 35 galaxies previously not described, a possible galaxy cluster and two galaxies that could be located in the Great Attractor Wall. The volunteers mainly discovered larger (d &gt; 12″) galaxies with a higher star-forming rate and likely missed galaxies with low star-forming rate or small galaxies. This work demonstrates that many galaxies in the Zone of Avoidance remain undiscovered in the GLIMPSE data set.

Keywords: Galaxy clusters, Great Attractor, Infrared galaxies, Spiral galaxies
The Large Far Ultraviolet Variations of α Cir A and α Cir B as Recorded by IUE and FUSE. Inspection of archival IUE spectra of the bright rapidly oscillating Ap star α Cir A reveal large flux variations from 1600 to 2000 Å over the 4.4790 day rotational period. At 1965 Å, where the flux reaches a maximum, the flux more than doubles between phases of maximum and minimum flux. These large flux variations are most likely caused by the passage of spots or belts of overabundant elements in the line of sight as the star rotates. The FUSE spectrum of α Cir B, the K5V dwarf close to α Cir A, contains several emission lines of O VI, C III and C II which are probably formed in the transition region and the chromosphere of this star. The O VI lines completely disappear over a timescale of a few days which probably reflects rotationaly modulated magnetic activity.

Keywords: K dwarf stars, Rapidly oscillating Ap star
Spectral Emission Features of SiO<SUB>2</SUB> Spheres. Silicate dust particles are part of many astronomical objects such as comets and circumstellar discs. In the spectrum, silicates exhibit a number of characteristic emission features. In this paper, we studied the contribution of quartz (SiO2) particles to these features. Using the Mie theory, calculations were made of the intensity of light scattered by such particles. Two spectral features were found in the spectrum—near 9 μm and near 20.5 μm. The main properties of these features are investigated. It is established, that the 9 μm feature is much narrower than the 20.5 μm; with an increase in the size of the scattering particle from very small values the position of spectral features (both 9 μm and 20.5 μm) shifts toward longer wavelengths; the 9 μm feature cannot be clearly seen with particle sizes greater than 18 μm, while the 20.5 μm feature is apparent even at particle radius 60 μm.

Keywords: Silicate grains, Spectral energy distribution
A Reader Friendly Formalism for the Circumstellar Material-supernova Ejecta Interaction Model. The interaction of a SN ejecta with a pre-existing circumstellar material (CSM) is one of the most promising energy sources for a variety of optical transients. Recently, a semi-analytic method developed by Chatzopoulos et al. (2012, hereafter CWV12) has been commonly used to describe the optical light curve behaviors under such a scenario. We find that the expressions for many key results in CWV12 are too complicated for readers to make order of magnitude estimation or parameter dependency judgement. Based on the same physical picture, here we independently re-derive all the formulae and re-establish a set of reader friendly formula expressions. Nevertheless, we point out and correct some minor errors or typos existing in CWV12.

Keywords: Light curves, Circumstellar shells, Supernovae
Origins of Mass Segregation in Stellar Clusters within the STARFORGE Simulations. Stellar clusters formed within Giant Molecular Clouds are mass segregated. This is either because massive stars are born at the center of the clusters, or because they migrate to the center due to gravitational interactions. We analyze a run from the STARFORGE simulation suite to identify what role the above processes play in determining mass segregation. We find that clusters begin as inversely- or non-mass segregated but contain separate mass-segregated star formation sites. As the cluster evolves, these substructures merge, and the overall cluster becomes more mass segregated due to gravitational interactions.

Keywords: Stellar physics, Computational astronomy, Star formation, Star clusters
A Search for the Guest Star Associated with Swift J1818-5937. We searched the possible historical records for the young magnetar Swift J1818-5937, and found a guest star in AD 1798 that might be associated with it.

Keywords: Neutron stars, Magnetars, History of astronomy, Supernovae
Testing the Accuracy of the Tangent Point Method for Determining the Milky Way's Inner Rotation Curve. The tangent point method (TPM) is commonly used to calculate the rotation curve of the inner portion of the Milky Way, relying on the assumption that along one line of sight, the point tangent to the Galactic center is the point where the observed radial velocity is an extremum. This work compares rotation curves derived from the TPM, using neutral hydrogen gas data, and direct measurements of stellar positions and velocities from the Gaia Satellite. The Gaia data indicate that the rotation curve based upon stellar kinematics is much shallower than that previously reported based on the TPM, especially in the inner regions of the Galaxy. Additionally, based on stellar kinematics, the locations of the extremum radial velocities and tangent points often differ. While these results are consistent with previously published simulations, future data from the Gaia satellite will allow for further confidence in determining an accurate rotation curve.

Keywords: Stellar kinematics, Milky Way dynamics, H I line emission, Galaxy kinematics, Galaxy rotation curves
Rapid Variability in the Wind from the White Dwarf Merger Candidate J005311. We analyze time-series spectroscopy of the white dwarf merger candidate J005311 and confirm the unique nature of its optical spectrum. We detect an additional broad emission feature peaking at 343 nm that was predicted in the Gvaramadze et al. (2019) models. Comparing ten spectra taken with the Large Binocular Telescope, we find significant variability in the profile of the strong O VI 381.1/383.4 nm emission feature. This appears to be caused by rapidly shifting subpeaks generated by clumpiness in the stellar wind of J005311. This line variability is similar to what is seen in many Wolf-Rayet stars. However, in J005311, the rate of motion of the subpeaks appears exceedingly high as they can reach 16,000 km s-1 in less than two hours.

Keywords: Evolved stars, Stellar mergers, White dwarf stars, Stellar winds, Wolf-Rayet stars
Long-timescale X-Ray Variability of BAL and Mini-BAL Quasars. We investigated the rest-frame ≈0.1-5 yr X-ray variability properties of an unbiased and uniformly selected sample of 24 broad absorption line (BAL) and 35 mini-BAL quasars, making it the largest representative sample used to investigate such variability. We find that the distributions of X-ray variability amplitudes of these quasar populations are statistically similar to that of non-BAL, radio-quiet (typical) quasars.

Keywords: X-ray quasars, Broad-absorption line quasar, Quasars