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TOI-6883.01: A Single-transit Planet Candidate Detected from TESS Res. Notes AAS Pub Date : 2024-02-26 G. Conzo, M. Moriconi
A new candidate exoplanet, proposed in ExoFOP by authors, it was promoted from TIC 393818343 to TOI-6883.01 at coordinates R.A.(J2000)20:41:10.01 decl.(J2000) + 3:38:17.87 in the Delphinus constellation and its distance is (93.73 ± 0.35) pc from Earth. The target star is a Sun-type having G0 class according to Skiff spectral classification and it has photometric magnitude V(Johnson) = 9.5 mag. We analyzed
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AI-enhanced Citizen Science Discovery of an Active Asteroid: (410590) 2008 GB140 Res. Notes AAS Pub Date : 2024-02-23 Colin Orion Chandler, Nima Sedaghat, William J. Oldroyd, Chadwick A. Trujillo, William A. Burris, Henry H. Hsieh, Jay K. Kueny, Kennedy A. Farrell, Jarod A. DeSpain, Mark Jesus Mendoza Magbanua, Scott S. Sheppard, Michele T. Mazzucato, Milton K. D. Bosch, Tiffany Shaw-Diaz, Virgilio Gonano, Al Lamperti, José A. da Silva Campos, Brian L. Goodwin, Ivan A. Terentev, Charles J. A. Dukes
We report the discovery of cometary activity emanating from Main-belt asteroid 410590 (2008 GB140), a finding facilitated, for the first time, by an artificial intelligence (AI) assistant. The assistant, TailNet, is a prototype we designed to enhance volunteer efforts of our Citizen Science project Active Asteroids, a NASA Partner program hosted on the Zooniverse platform. Our follow-up investigation
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An Upper Limit to Differential Magnification Effects in Strongly Gravitationally Lensed Galaxies Res. Notes AAS Pub Date : 2024-02-23 Stephen Serjeant
Differential magnification is now well-known to distort the spectral energy distributions of strongly gravitationally lensed galaxies. However, that does not mean that any distortions are possible. Here I prove an analytic upper bound to differential magnification effects. For example, a thermal or sub-thermal CO ladder cannot be made to appear super-thermal just from gravitational lensing, and the
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2016 UU121: An Active Asteroid Discovery via AI-enhanced Citizen Science Res. Notes AAS Pub Date : 2024-02-23 Nima Sedaghat, Colin Orion Chandler, William J. Oldroyd, Chadwick A. Trujillo, William A. Burris, Henry H. Hsieh, Jay K. Kueny, Kennedy A. Farrell, Jarod A. DeSpain, Mark Jesus Mendoza Magbanua, Scott S. Sheppard, Michele T. Mazzucato, Milton K. D. Bosch, Tiffany Shaw-Diaz, Virgilio Gonano, Al Lamperti, José A. da Silva Campos, Brian L. Goodwin, Ivan A. Terentev, Charles J. A. Dukes
We report the discovery of an active asteroid, 2016 UU121, for the first time via artificial intelligence-enhanced classification, informed by our NASA Partner program Active Asteroids, a Citizen Science project hosted on the Zooniverse platform. The early version of our deep neural network, TailNet, identified potential activity associated with 2016 UU121 in 40 Dark Energy Camera (DECam) images from
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Quantifying Solar Radiation Pressure Effects on Dust at Small Heliocentric Distances Res. Notes AAS Pub Date : 2024-02-20 Jake Hanlon, Geraint H. Jones, Vinay Williams
The dynamics of dust grains has traditionally been modeled under the assumption that the ratio of the opposing solar radiation pressure and gravitational forces is fixed for an individual, unchanging grain. However, at small heliocentric distances, this assumption is inaccurate, as the variation in radiation pressure force with heliocentric distance does not follow an inverse square law there, as the
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extrabol: A Python Package for Estimating Bolometric Light Curves of Thermal Transients Res. Notes AAS Pub Date : 2024-02-15 Ian Thornton, V. Ashley Villar, Sebastian Gomez, Griffin Hosseinzadeh
We introduce a new, open-source, Python-based package, extrabol, for inferring the bolometric light curve evolution of extragalactic thermal transients. extrabol uses non-parametric Gaussian Process regression for light curve estimation that requires minimal user interaction. extrabol is available via GitHub.
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Reevaluating LSST’s Capability for Time Delay Measurements in Quasar Accretion Disks Res. Notes AAS Pub Date : 2024-02-14 F. Pozo Nuñez, B. Czerny, S. Panda, A. Kovacevic, W. Brandt, K. Horne, on behalf of the LSST AGN Science Collaboration
The Legacy Survey of Space and Time at the Vera C. Rubin Observatory is poised to observe thousands of quasars using the Deep Drilling Fields (DDF) across six broadband filters over a decade. Understanding quasar accretion disk (AD) time delays is pivotal for probing the physics of these distant objects. Pozo Nuñez et al. has recently demonstrated the feasibility of recovering AD time delays with accuracies
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An Enigmatic High Excitation Nebula in IC 1613 Dwarf Galaxy Res. Notes AAS Pub Date : 2024-02-09 S. Taibi, M. M. Roth, G. Battaglia, S. Kamann
We report the serendipitous discovery of a high-excitation nebula in the Local Group dwarf galaxy IC 1613. The nebula shows spectral features typical of a planetary nebula (PN), but its physical size makes it an order of magnitude larger than observed for this type of object, if indeed it belongs to IC 1613. We hypothesise that it may be an example of an over-luminous PN, a still unexplained phenomenon
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The Application of Machine Learning to Quasar and Seyfert Classification Res. Notes AAS Pub Date : 2024-02-09 Vivek Abraham, Joel Deville, Garv Kinariwala
Machine learning can be utilized to classify spectra flagged as Active Galactic Nuclei (AGNs) belonging to Seyferts or Quasars, expediting data collection and aiding in analyzing the AGN types. While many properties of Seyferts and Quasars can be used as feature points in training a machine learning model, one relatively available property with high information density is the spectra of the AGN types
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Radio Properties of the Quasar J1718+4239, the Proposed Source of the Neutrino Event IceCube-201221A Res. Notes AAS Pub Date : 2024-02-07 Krisztina Perger, Sándor Frey, Krisztina É. Gabányi, Emma Kun
NVSS J171822+423948 was recently identified as the most probable counterpart of the neutrino event IC-201221A. Based on the highly variable γ-ray, optical, and mid-infrared emission, the dates of the flaring events, and optical spectroscopy in the field of interest, this object was classified as a neutrino-emitting blazar candidate. Since its radio properties were not discussed in detail, we present
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Faint Comet Detection with Unistellar eVscopes Res. Notes AAS Pub Date : 2024-02-06 Ariel Graykowski, Samantha Hemmelgarn, Thomas M. Esposito, Franck Marchis, David Koster, Darren Rivett, Masao Shimizu
We present eVscope observations of comets 12P/Pons-Brooks and C/2023 A3 (Tsuchinshan-ATLAS) when their magnitudes were greater than 16th magnitude. From a set of two observations of 12P taken on 2023 June 19 and 20, we measure an apparent magnitude of G = 16.59 ± 0.31. From four sets of observations of C/2023 A3 taken on 2023 April 14, 25, 26, and May 9, we measure apparent magnitudes of G = 16.78 ± 0
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Comparison of Convolutional Neural Networks and Random Forest Classifiers for Strong Gravitational Lens Identification Res. Notes AAS Pub Date : 2024-02-06 Maadhav Kothuri, Surain Saigal, Sasidhar Ayyalasomayajula
Strong gravitational lenses have been instrumental in providing insight into various astronomical problems, including analyzing the dark matter distribution of the universe. Effective identification of these events is made possible through machine learning algorithms, with many recent studies focusing on neural networks. However, very few have investigated the tradeoffs between different algorithms
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Hidden Companions to Intermediate-mass Stars. XV. Discovery of a 1.2M ⊙, 8.4 au Companion to the δ Scuti star HIP 41375 = 2 Hydrae* * Based on observations collected at the European Southern Observatory, Chile, Program ID 110.241W.001. Res. Notes AAS Pub Date : 2024-02-06 Idel Waisberg, Ygal Klein, Boaz Katz
2 Hydrae is a nearby M Aa = 1.66M ⊙ δ Scuti star with strong astrometric evidence for a close companion in addition to its known M B = 0.20M ⊙ M dwarf companion at 530 au. Here we report on a VLTI/GRAVITY near-infrared interferometric observation that reveals the close companion to be a M Ab = 1.18M ⊙ star at a projected separation ρ = 168 mas ↔ 8.4 au. This triple system is a potential progenitor
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Flares from Space Debris in LSST Images Res. Notes AAS Pub Date : 2024-02-02 Abraham Loeb
Owing to the exceptional sensitivity of the Vera C. Rubin Observatory, we predict that its upcoming LSST images will be contaminated by numerous flares from centimeter-scale space debris in Low Earth Orbits (LEO). Millisecond-duration flares from these LEO objects are expected to produce detectable image streaks of a few arcseconds with AB magnitudes brighter than 14.
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Recovery and Classification of Spherules from the Pacific Ocean Site of the CNEOS 2014 January 8 (IM1) Bolide Res. Notes AAS Pub Date : 2024-01-31 A. Loeb, T. Adamson, S. Bergstrom, R. Cloete, S. Cohen, Kevin Conrad, Laura Domine, H. Fu, C. Hoskinson, E. Hyung, S. B. Jacobsen, M. Kelly, J. Kohn, E. Lard, F. Laukien, J. Lem, R. McCallum, R. Millsap, C. Parendo, M. I. Pataev, C. Peddeti, J. Pugh, S. Samuha, D. D. Sasselov, M. Schlereth, J. Siler, A. Siraj, P. M. Smith, R. Tagle, J. Taylor, R. Weed, A. Wright, J. Wynn
We have conducted an extensive towed-magnetic-sled survey during the period 2023 June 14–28, over the seafloor about 85 km north of Manus Island, Papua New Guinea, centered around the calculated path of the bolide CNEOS 2014 January 8 (IM1). We found about 850 spherules of diameter 0.05–1.3 mm in our samples. They were analyzed by microXRF, Electron Probe Microanalyzer and ICP Mass spectrometry. We
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Thirty Bright High Velocity B, A, and F Stars that may have Late-type Companions Res. Notes AAS Pub Date : 2024-01-31 Mudumba Parthasarathy
I found thirty high velocity stars that have large V − K values compared to standard stars of similar spectral types indicating the possible presence of late-type companion stars. All these thirty stars are relatively bright nearby stars with accurate Gaia DR3 parallaxes and radial velocities. There is hardly any relevant literature on these stars. There are 18 high galactic latitude stars in this
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A Radio Technosignature Search of Six Resonant Sub-Neptunes Orbiting HD 110067 Res. Notes AAS Pub Date : 2024-01-31 Carmen Choza, Steve Croft, Andrew P. V. Siemion, Sofia Sheikh, Matthew Lebofsky, David H. E. MacMahon, Jamie Drew, S. Pete Worden
We describe archival observations and analysis of the HD 110067 planetary system using the Green Bank Telescope (GBT) as part of the Breakthrough Listen search for technosignatures. The star hosts six sub-Neptune planets in resonant orbits, and we tune the drift rate range of our search to match the properties of the system derived by Luque et al. Our observations cover frequencies from 1 to 11.2 GHz
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Virial Velocities for Stellar Flybys with Planetary Disks in Star Formation Regions Res. Notes AAS Pub Date : 2024-01-30 Juan J. Jiménez-Torres, Alvaro Alvarez-Candal
In this work, we show the effect of different velocities of stellar encounters with planetary disks to support the use of virial or constant velocities in simulations of typical star-forming clusters; the variety of observed member velocity values in such objects can cause concern when selecting velocities for simulations. In this work, we employ different velocities from 1.5 to 10 km s−1 with constant
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Dynamical Classifications of Multi-opposition TNOs as of 2023 December Res. Notes AAS Pub Date : 2024-01-30 Kathryn Volk, Christa Van Laerhoven
We report the dynamical classifications of 3357 observed outer solar system objects listed as transneptunian objects (TNOs) or Centaurs by the Minor Planet Center. We use the Gladman et al. classification scheme to identify 28 Jupiter-coupled objects (all secure), 168 Centaurs (all secure), 234 scattering TNOs (70 secure/164 insecure), 204 detached TNOs (118 secure/86 insecure), 1650 classical TNOs
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Non-detection of Radio Pulsations in the High-mass X-Ray Binary V0332+53 During Quiescence Res. Notes AAS Pub Date : 2024-01-30 Jakob van den Eijnden, Kaustubh Rajwade
Following recent discoveries of ultra-long-period radio-loud neutron stars located beyond death line models in the pulsar period-period derivative diagram, we performed a radio pulsation search in the high-mass X-ray binary V0332+53 during quiescence. Although the period and magnetic field of the neutron star in this binary make it the most promising high-mass X-ray binary to explore for this purpose
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Is the Far-ultraviolet Flux of 21 Com Anticorrelated to its Optical Brightness? Res. Notes AAS Pub Date : 2024-01-30 Richard Monier
The comparison of 20 ultraviolet spectra of 21 Com taken over continuous 24 hr to the optical counts collected by the Fine Error Sensor on board IUE reveals that large variations observed shortwards of 1700 Å occur in anti-phase with the optical brightness for part of the observations but not all. In this data, the FUV flux at 1540 Å reaches a minimum at rotational phase 0.32 and increases afterwards
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shock_cooling_curve: A Python-based Package for Extensive and Efficient Modeling of Shock Cooling Emission in Supernovae Res. Notes AAS Pub Date : 2024-01-30 Padma Venkatraman, Wynn Jacobson-Galán
The light-curve evolution of a supernova contains information on the exploding star. Early-time photometry of a variety of explosive transients, including Calcium-rich transients and type IIb/Ibc and IIP supernovae shows evidence for an early light curve peak as a result of the explosion’s shock wave passing through extended material (i.e., shock cooling emission (SCE)). Analytic modeling of the SCE
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A Possible Orbital Period of MAXI J0158-744 Res. Notes AAS Pub Date : 2024-01-30 Alex C. H. Chan, K. L. Li
Optical Gravitational Lensing Experiment (OGLE) has observed Monitor of All-sky X-ray Image J0158-744 for at least 10 yr since the X-ray/optical burst in 2011, which is a Be+ White Dwarf Supersoft source. By analyzing the OGLE light curve, we noticed that the optical brightness was changing periodically, indicating a possible orbital period of 439−80+114 days.
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A Note on the Flattop Velocity Distribution in Space Plasmas Res. Notes AAS Pub Date : 2024-01-29 Seiji Zenitani
A flattop velocity distribution is one of the most characteristic distributions in space plasmas. I discuss its properties using the generalized beta-prime distribution. Then I present a sampling algorithm for generating the flattop distribution in particle-in-cell and Monte Carlo simulations.
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A Size Estimate for Galaxy GN-z11 Res. Notes AAS Pub Date : 2024-01-29 James O. Baldwin, Erica Nelson, Benjamin D. Johnson, Pascal A. Oesch, Sandro Tacchella, Garth D. Illingworth, Justus Gibson, Abby Hartley
GN-z11 is the highest redshift galaxy spectroscopically confirmed with the Hubble Space Telescope (HST). Previous measurements of the effective radius of GN-z11 utilized galfit, which is not optimized to measure structural parameters for such a faint, distant object. Using new software called forcepho, we derive a size from images in the F160W band obtained both from the complete CANDELS survey and
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Discovered the Long-term Variation of the Variable Star CzeV818 Res. Notes AAS Pub Date : 2024-01-25 Ivo Peretto, Stefano Lora, Matilde Barbieri, Lorenzo Sassaro, Giovanni Furlato, William Rivato, Giuseppe Peretto, Gianni Galli, Simone Gazzetta
In this study we describe the reclassification of the variable star CzeV818, discovered in 2015 by Pavel Cagas (Skarka et al. 2017), which was cataloged as a delta Scuti variable. From the photometric study performed with the telescopes of the SSV-UAI-GRAV (Unione Astrofili Italiani, Variable Star Section), All-Sky Automated Survey for Supernovae (Kochanek et al. 2017) (ASAS-SN) and Zwicky Transient
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The Gravitational Wave AfterglowPy Analysis (GWAPA) webtool Res. Notes AAS Pub Date : 2024-01-19 R. A. J. Eyles-Ferris, H. van Eerten, E. Troja, P. T. O’Brien
We present the first release of the Gravitational Wave AfterglowPy Analysis (GWAPA) webtool (Available at https://gwapa.web.roma2.infn.it/). GWAPA is designed to provide the community with an interactive tool for rapid analysis of gravitational wave afterglow counterparts and can be extended to the general case of gamma-ray burst afterglows seen at different angles. It is based on the afterglowpy package
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Ultraviolet and Blue Optical Imaging of UVCANDELS Res. Notes AAS Pub Date : 2024-01-19 Xin Wang, Harry I. Teplitz, Lei Sun, Marc Rafelski, Norman Grogin, Laura Prichard, Ben Sunnquist, Anahita Alavi, Rogier A. Windhorst, Anton M. Koekemoer, Teresa Ashcraft, Micaela Bagley, Ivano Baronchelli, Guillermo Barro, Alex Blanche, Gabriel Brammer, Adam Broussard, Timothy Carleton, Nima Chartab, Yingjie Cheng, Alex Codoreanu, Seth Cohen, James Colbert, Christopher Conselice, Y. Sophia Dai, Behnam
The UltraViolet Imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) survey provided ultraviolet F275W imaging with coordinated parallel optical F435W imaging in four of the five CANDELS fields: GOODS-N, GOODS-S, EGS, and COSMOS, covering a total area of ∼426 arcmin2. UVCANDELS takes primary WFC3/UVIS F275W exposures at a uniform 3-orbit depth and ACS F435W
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Controlling Randomization in Astronomy Simulations Res. Notes AAS Pub Date : 2024-01-19 Megan E. Schwamb, Jeremy Kubica, Mario Jurić, Drew Oldag, Maxine West, Melissa DeLucchi, Matthew J. Holman
As the primary requirement, correctly implementing and controlling random number generation is vital for a range of scientific analyses and simulations across astronomy and planetary science. Beyond advice on how to set the seed, there is little guidance in the literature for how best to handle pseudo-random number generation in the current era of open-source astronomical software development. We present
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Seventeen 2 Micron All Sky Survey (2MASS) Hypervelocity Stars (HVS) from Gaia DR3 Res. Notes AAS Pub Date : 2024-01-18 Mudumba Parthasarathy
As part of an ongoing search for hypervelocity stars I found seventeen two micron all sky survey sources with Gaia G magnitudes less than 16.0 and radial velocities less than −600 km s−1. All these stars are brighter in the K band when compared with their V and G magnitudes. Ten of these (including three carbon stars) are long period variable stars of Mira type. One is a relatively nearby high proper
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A Bigger Cloud 9? New H i Observations of the RELHIC Candidate M94- Cloud 9 Res. Notes AAS Pub Date : 2024-01-18 Ananthan Karunakaran, Kristine Spekkens
We present new H i observations of the REionization-Limited H i Cloud (RELHIC) candidate, M94-CL9, detected around M94 by Zhou et al. using the Five-hundred-meter Aperture Spherical Telescope (FAST). M94-CL9's H i properties as detected by FAST are consistent with a RELHIC as noted by Benitez-Llambay & Navarro. Our observations with the Robert C. Byrd Green Bank Telescope detect greater H i emission
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Gnuastro: Measuring Radial Profiles from Images Res. Notes AAS Pub Date : 2024-01-17 Raúl Infante-Sainz, Mohammad Akhlaghi, Sepideh Eskandarlou
Radial profiles play a crucial role in the analysis and interpretation of astronomical data, facilitating the extraction of spatial information. However, highly customizable (for different scenarios) measurements over each elliptical annulus can be challenging. In response, we present astscript-radial-profile, which is part of Gnuastro from version 0.15 and has an extensive documentation. A convenient
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Bug Found in Gaia query_object Functions of Astroquery’s Python Package Res. Notes AAS Pub Date : 2024-01-16 David Sweeney, Alberto Krone-Martins
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
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The Once-canceled Habitable-zone Super-Earth Gliese 581d Might Indeed Exist! Res. Notes AAS Pub Date : 2024-01-16 Manfred Cuntz, Scott G. Engle, Edward F. Guinan
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
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Detection Sensitivities from the Anglo-Australian Planet Search Res. Notes AAS Pub Date : 2024-01-12 Robert A. Wittenmyer
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 > 0.3 M J) from the now-completed Anglo-Australian Planet Search. In this work, I deliver the detailed detection
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Activity Discovered on Mars-Crossing Jupiter Family Comet 2018 OR by Citizen Scientists Res. Notes AAS Pub Date : 2024-01-11 Kennedy A. Farrell, Colin Orion Chandler, William J. Oldroyd, Chadwick A. Trujillo, William A. Burris, Henry H. Hsieh, Jay K. Kueny, Jarod A. DeSpain, Mark Jesus Mendoza Magbanua, Nima Sedaghat, Scott S. Sheppard, Michele T. Mazzucato, Milton K. D. Bosch, Tiffany Shaw-Diaz, Virgilio Gonano, Al Lamperti, José A. da Silva Campos, Brian L. Goodwin, Ivan A. Terentev, Charles J. A. Dukes
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
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NE2001p: A Native Python Implementation of the NE2001 Galactic Electron Density Model Res. Notes AAS Pub Date : 2024-01-09 Stella Koch Ocker, James M. Cordes
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
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A Comparison of Star-formation Histories Derived from UniverseMachine and LEGA-C at 0.6 < z < 1 Res. Notes AAS Pub Date : 2024-01-09 Cecilia Steel, Alan Pearl, Yasha Kaushal, Rachel Bezanson
In this work, we compare star formation histories of massive (10.5
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Evaluation of a Magnetic Field Inversion Method Using Only Stokes I Res. Notes AAS Pub Date : 2024-01-09 Abduhla Ali, Andrea Diercke, Stefan Hofmeister, Christoph Kuckein, Daniel Wolf Savin, Michael Hahn
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
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Light Curve of HT Cassiopeiae Res. Notes AAS Pub Date : 2024-01-09 Elizabeth A. Lawrence, Christopher M. Copperwheat
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
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James Webb Space Telescope Spectra of Cold Brown Dwarfs are Well-reproduced by Phosphine-free, Diabatic, ATMO2020++ Models Res. Notes AAS Pub Date : 2024-01-09 S. K. Leggett, Pascal Tremblin
James Webb Space Telescope (JWST) mid-infrared spectra of cold brown dwarfs (BDs) are becoming available. In Leggett & 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
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Gnuastro: Visualizing the Full Dynamic Range in Color Images Res. Notes AAS Pub Date : 2024-01-08 Raúl Infante-Sainz, Mohammad Akhlaghi
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
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The Abundance Pattern of The A2.5V Star HD 176687 (ζ Sagitarii A) In A Triple System Res. Notes AAS Pub Date : 2024-01-08 Richard Monier
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
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Prospects for Connections to the Outer Halo of the Milky Way with LSST Res. Notes AAS Pub Date : 2024-01-08 David A. Gonzalez, Kathryn V. Johnston
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
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Galactic Bulge Hypervelocity (HVS) RR Lyrae Variable Stars and One High Galactic Latitude HVS HB Star Res. Notes AAS Pub Date : 2024-01-08 Mudumba Parthasarathy
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
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AstroLLaMA-Chat: Scaling AstroLLaMA with Conversational and Diverse Datasets Res. Notes AAS Pub Date : 2024-01-08 Ernest Perkowski, Rui Pan, Tuan Dung Nguyen, Yuan-Sen Ting, Sandor Kruk, Tong Zhang, Charlie O’Neill, Maja Jablonska, Zechang Sun, Michael J. Smith, Huiling Liu, Kevin Schawinski, Kartheik Iyer, Ioana Ciucă, UniverseTBD
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
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Detection of Tm ii Lines in the Spectra of Two s-process Rich Stars Res. Notes AAS Pub Date : 2024-01-08 Laimons Začs, Bogdan Kaminsky, Kārlis Puķı̄tis
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, logϵ(Tm)≃0
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M31N 2013-10c: A Newly Identified Recurrent Nova in M31 Res. Notes AAS Pub Date : 2024-01-04 Allen W. Shafter, Kamil Hornoch, Hana Kučáková, Petr Fatka, Jingyuan Zhao, Xing Gao, Shahidin Yaqup, Tuhong Zhong, Ali Esamdin, Chunhai Bai, Na Wang, Paul Benni, Aiden Luo, Ilana Yousuf
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
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GRB 230911A: The First Discovery of a Fermi GRB Optical Counterpart with the Gravitational-wave Optical Transient Observer (GOTO) Res. Notes AAS Pub Date : 2024-01-04 S. Belkin, B. P. Gompertz, A. Kumar, K. Ackley, D. K. Galloway, F. Jiménez-Ibarra, T. L. Killestein, D. O’Neill, K. Wiersema, D. B. Malesani, A. J. Levan, J. Lyman, M. J. Dyer, K. Ulaczyk, D. Steeghs, V. S. Dhillon, P. O’Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Pallé, D. Pollacco, S. Awiphan, U. Burhanudin, P. Chote, A. Chrimes, E. Daw, C. Duffy, R. Eyles-Ferris, B. Godson
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
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The Late-epoch, Intermediate Excitation Spectrum of the Nova V612 Scuti Res. Notes AAS Pub Date : 2024-01-03 Richard J. Rudy, John P. Subasavage, Jon C. Mauerhan
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
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Detecting the Undetected: Overcoming Biases in Gravitational-wave Population Studies Res. Notes AAS Pub Date : 2024-01-03 Ryan Raikman, Simone Bavera, Tassos Fragos
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
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AI Can Identify Solar System Instability Billions of Years in Advance Res. Notes AAS Pub Date : 2024-01-03 Dorian S. Abbot, J. D. Laurence-Chasen, Robert J. Webber, David M. Hernandez, Jonathan Weare
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
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Spectral Fit Residuals as an Indicator to Increase Model Complexity Res. Notes AAS Pub Date : 2024-01-03 Anshuman Acharya, Vinay L. Kashyap
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
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CO and Atomic Line Emission from the Young Stellar Object V1331 Cygni Res. Notes AAS Pub Date : 2023-12-26 Richard J. Rudy, Ray W. Russell, Michael L. Sitko
The infrared spectrum of the young disk star V1331 Cygni shows rare atomic emission lines from several species including C i, O i, Na i, Mg i, Al i, Si i, Ca i, Fe i, and probably S i. The presence of H i emission but the absence of N i recombination lines indicates excitation by a comparatively cool source unable to ionize nitrogen. Measurements of both the fundamental and first overtone emission
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Comparison between Analytical and Numerical Results for Twisted Magnetosphere of Magnetars Res. Notes AAS Pub Date : 2023-12-22 H. Tong
The analytical calculations for twisted magnetosphere of magnetars are compared with recent numerical simulations. A larger polar cap, a smaller magnetospheric opening radius in previous analytical modelings are confirmed by the numerical simulations. In the case of magnetars, the particle outflow luminosity in the open field line regions may be powered by the magnetic energy.
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Distance to Leo A Based on a Post-asymptotic-giant-branch Star Res. Notes AAS Pub Date : 2023-12-22 Chow-Choong Ngeow
A yellow post-asymptotic-giant-branch (PAGB) star was recently identified in the dwarf galaxy Leo A. Using this yellow PAGB star, I derived a distance of 794.3 ± 10.0 kpc to Leo A, illustrating the yellow PAGB star can be used as a distance indicator.
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A Fully Explicit Integrator for Modeling Astrophysical Reactive Flows Res. Notes AAS Pub Date : 2023-12-22 Parker Johnson, Michael Zingale, Eric T. Johnson, Alexander Smith, Kyle E. Niemeyer
Simulating complex astrophysical reacting flows is computationally expensive—reactions are stiff and typically require implicit integration methods. The reaction update is often the most expensive part of a simulation, which motivates the exploration of more economical methods. In this research note, we investigate how the explicit Runge–Kutta–Chebyshev (RKC) method performs compared to an implicit
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The Importance of Neural Network Hyperparameters in Determining Age Inference Quality Res. Notes AAS Pub Date : 2023-12-20 Jamie Tayar, Zachary R. Claytor, Quentin Fox, Liberty Mallison, Ezra Rader, Ryan Spivey, Denise Yudovich, Jack Moreland, Rachel Pinsky, Penelope Planet, Artemis Theodoridis, Jacod Williams, Caeli Benyacko, Sydney Phelps Comstock, Nadia Hansen, Marcus Mynatt, Ben C. Sherwin, Daniel Agharahimi, Amro Al-Wir, Jacob Boesger, JR Davis, Austin Fraley, Aaditya Kaushal, Trent La Sage, Anna Grace Lube, Rachel
To estimate precise ages for large samples across the galaxy, it has become common to train machine learning models on smaller, well-characterized samples of stars and then apply them to larger samples. As part of an undergraduate course, we used this technique to train a simple neural network with varying nodes and layers using ∼11,800 ages from the upcoming APOGEE-Kepler-3 sample of stars. We find
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Synthesis of the 4400–4600 Å Spectral Range for the A2.5V star HD 176687 (ζ Sagitarii A) Res. Notes AAS Pub Date : 2023-12-20 Richard Monier
The synthesis of a high resolution high signal-to-noise spectrum of HD 176687 from 4400 to 4600 Å allows the determination of LTE abundances for magnesium, calcium, scandium, titanium, chromium, iron, nickel and barium. This A2.5V star has recently been found to be the most massive star in a triple system. Magnesium and calcium are found to have a solar abundance. Scandium and titanium are depleted
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Baked before Breaking into Bits: Evidence for Atira-type Asteroid Splits Res. Notes AAS Pub Date : 2023-12-20 Carlos de la Fuente Marcos, Raúl de la Fuente Marcos
Current near-Earth asteroid orbital models cannot reproduce the observed populations close to the Sun. Supercatastrophic and tidal disruptions may explain the differences between theoretical models and observational data. Here, we explore the distributions of mutual nodal distances and the angular separation of perihelia of the known Atiras looking for evidence of past splittings. We find a number