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arXiv 2024年

作者： Martínez, Romy Rodríguez Eastman, Jason D. Collins, Karen A. Rodriguez, Joseph E. Charbonneau, David Quinn, Samuel N. Latham, David W. Ziegler, Carl Brahm, Rafael Fairnington, Tyler R. Ulmer-Moll, Solène Stassun, Keivan G. Suarez, Olga Guillot, Tristan Hobson, Melissa J. Winn, Joshua N. Kanodia, Shubham Schlecker, Martin Butler, R.P. Crane, Jeffrey D. Shectman, Steve Teske, Johanna K. Osip, David Beletsky, Yuri Battley, Matthew P. Psaridi, Angelica Figueira, Pedro Lendl, Monika Bouchy, François Udry, Stéphane Kunimoto, Michelle Mékarnia, Djamel Abe, Lyu Trifonov, Trifon Pinto, Marcelo Tala Eberhardt, Jan Espinoza, Nestor Henning, Thomas Jordán, Andrés Rojas, Felipe I. Barkaoui, Khalid Relles, Howard M. Srdoc, Gregor Collins, Kevin I. Seager, Sara Shporer, Avi Vezie, Michael Hedges, Christina Mireles, Ismael Center for Astrophysics Harvard & Smithsonian 60 Garden St CambridgeMA02138 United States Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48824 United States Department of Physics Engineering and Astronomy Stephen F. Austin State University 1936 North St NacogdochesTX75962 United States Facultad de Ingeniera y Ciencias Universidad Adolfo Ibáñez Av. Diagonal las Torres 2640 Peñalolén Santiago Chile Millennium Institute for Astrophysics Chile Centre for Astrophysics University of Southern Queensland West Street ToowoombaQLD4350 Australia Observatoire astronomique de l Université de Genève 51 Chemin Pegasi Versoix1290 Switzerland Physikalisches Institut University of Bern Gesellschaftsstrasse 6 Bern3012 Switzerland Department of Physics and Astronomy Vanderbilt University NashvilleTN37235 United States Université Côte d’Azur Observatoire de la Côte d’Azur CNRS Laboratoire Lagrange Bd de l’Observatoire CS 34229 Nicecedex 4 06304 France Department of Astrophysical Sciences Princeton University PrincetonNJ08544 United States Carnegie Science Earth and Planets Laboratory 5241 Broad Branch Road NW WashingtonDC20015 United States Department of Astronomy Steward Observatory University of Arizona TucsonAZ85721 United States Department of Physics Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology 77 Massachusetts Avenue CambridgeMA02139 United States Max-Planck-Institut für Astronomie Königstuhl 17 HeidelbergD-69117 Germany Department of Astronomy Sofia University "St Kliment Ohridski" 5 James Bourchier Blvd SofiaBG-1164 Bulgaria Landessternwarte Zentrum für Astronomie der Universität Heidelberg Königstuhl 12 HeidelbergD-69117 Germany Space Telescope Science Institute BaltimoreMD21218 United States Instituto de Astrofísica Facultad de Física Pontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860 Sant

We present the detection and characterization of TOI-4994b (TIC 277128619b), a warm Saturn-sized planet discovered by the NASA Transiting Exoplanet Survey Satellite (TESS). TOI-4994b transits a G-type star (V = 12.6 mag) with a mass, radius, and effective temperature of M☆ = 1.005+0.064−0.061M☉, R☆ = 1.055+0.040−0.037R☉, and Teff = 5640±110 K. We obtained follow-up ground-based photometry from the Las Cumbres Observatory (LCO) and the Antarctic Search for Transiting ExoPlanets (ASTEP) telescopes, and we confirmed the planetary nature of TOI-4994b with multiple radial velocity observations from the PFS, CHIRON, HARPS, FEROS, and CORALIE instruments. From a global fit to the photometry and radial velocities, we determine that TOI-4994b is in a 21.5-day, eccentric orbit (e = 0.32 ± 0.04) and has a mass of MP = 0.280+0.037−0.034MJ, a radius of RP = 0.762+0.030−0.027RJ, and a Saturn-like bulk density of ρp = 0.78+0.16−0.14 g/cm3. We find that TOI-4994 is a potentially viable candidate for follow-up stellar obliquity measurements. TOI-4994b joins the small sample of warm Saturn analogs and thus sheds light on our understanding of these rare and unique worlds. © 2024, CC BY.

关键词： NASA

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High-quality high-order harmonic generation through preplasma truncation

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Physical Review E 2019年第5期100卷 053207-053207页

作者： B. Y. Li F. Liu M. Chen Z. Y. Chen X. H. Yuan S. M. Weng T. Jin S. G. Rykovanov J. W. Wang Z. M. Sheng J. Zhang Key Laboratory for Laser Plasmas (MoE) School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Collaborative Innovation Center of IFSA (CICIFSA) Shanghai Jiao Tong University Shanghai 200240 China National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid Physics China Academy of Engineering Physics Mianyang 621999 China Zhiyuan College Shanghai Jiao Tong University Shanghai 200240 China Center for Computational and Data-Intensive Science and Engineering Skolkovo Institute of Science and Technology Moscow 121205 Russia Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 200240 China SUPA Department of Physics University of Strathclyde Glasgow G4 0NG United Kingdom

By introducing preplasma truncation to cases with an initial preplasma scale length larger than 0.2λ, the efficiency of high-order harmonics generated from relativistic laser-solid interactions can be enhanced by more than one order of magnitude and the angular spread can be confined into near-diffraction-limited divergence. Numerical simulations show that density truncation results in more compact oscillation of the surface electron sheet and the curvature of the reflection surface for the driving laser is greatly reduced. This leads to an overall improvement in the harmonic beam quality. More importantly, density truncation makes the harmonic generation weakly dependent on the preplasma scale length, which provides a way to relax the extremely high requirement on the temporal contrast of the driving laser pulse. A feasible scheme to realize the required preplasma truncation is also proposed and demonstrated by numerical simulations.

关键词： High intensity laser-plasma interactions High-order harmonic generation X-ray generation in plasmas

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The Early Light Curve of SN 2023bee: Constraining Type Ia Supernova Progenitors the Apian Way

arXiv

引用

arXiv 2023年

作者： Hosseinzadeh, Griffin Sand, David J. Sarbadhicary, Sumit K. Ryder, Stuart D. Jha, Saurabh W. Dong, Yize Bostroem, K. Azalee Andrews, Jennifer E. Hoang, Emily Janzen, Daryl Jencson, Jacob E. Lundquist, Michael Meza Retamal, Nicolas E. Pearson, Jeniveve Shrestha, Manisha Valenti, Stefano Wyatt, Samuel Farah, Joseph Howell, D. Andrew McCully, Curtis Newsome, Megan Gonzalez, Estefania Padilla Pellegrino, Craig Terreran, Giacomo Alzaabi, Muzoun Green, Elizabeth M. Gurney, Jessica L. Milne, Peter A. Ridenhour, Kaycee I. Smith, Nathan Robles, Paulina Soto Kwok, Lindsey A. Schwab, Michaela Gromadzki, Mariusz Buckley, David A.H. Itagaki, Koichi Hiramatsu, Daichi Chomiuk, Laura Lundqvist, Peter Haislip, Joshua Kouprianov, Vladimir Reichart, Daniel E. Steward Observatory University of Arizona 933 North Cherry Avenue TucsonAZ85721-0065 United States Center for Cosmology and AstroParticle Physics Ohio State University 191 West Woodruff Avenue ColumbusOH43210-1117 United States School of Mathematical and Physical Sciences Macquarie University SydneyNSW2109 Australia Astrophysics and Space Technologies Research Centre Macquarie University SydneyNSW2109 Australia Department of Physics and Astronomy Rutgers The State University of New Jersey 136 Frelinghuysen Road PiscatawayNJ08854-8019 United States Department of Physics and Astronomy University of California Davis 1 Shields Avenue DavisCA95616-5270 United States Gemini Observatory 670 North A‘ohoku Place HiloHI96720-2700 United States Department of Physics & Engineering Physics University of Saskatchewan 116 Science Place SaskatoonSKS7N 5E2 Canada W. M. Keck Observatory 65-1120 Māmalahoa Highway KamuelaHI96743-8431 United States Department of Astronomy University of Washington 3910 15th Avenue NE SeattleWA98195-0002 United States Las Cumbres Observatory 6740 Cortona Drive Suite 102 GoletaCA93117-5575 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Astronomical Observatory University of Warsaw Al. Ujazdowskie 4 Warszawa00-478 Poland South African Astronomical Observatory P.O. Box 9 Observatory7935 South Africa Department of Physics University of the Free State P.O. Box 339 Bloemfontein9300 South Africa Department of Astronomy University of Cape Town Private Bag X3 Rondebosch7701 South Africa Itagaki Astronomical Observatory Yamagata990-2492 Japan Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138-1516 United States The NSF AI Institute for Artificial Intelligence and Fundamental Interactions United States Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48

We present very early photometric and spectroscopic observations of the Type Ia supernova (SN Ia) 2023bee, starting about 8 hr after the explosion, which reveal a strong excess in the optical and nearest UV (U and UVW1) bands during the first several days of explosion. This data set allows us to probe the nature of the binary companion of the exploding white dwarf and the conditions leading to its ignition. We find a good match to the Kasen model in which a main-sequence companion star stings the ejecta with a shock as they buzz past. Models of double detonations, shells of radioactive nickel near the surface, interaction with circumstellar material, and pulsational delayed detonations do not provide good matches to our light curves. We also observe signatures of unburned material, in the form of carbon absorption, in our earliest spectra. Our radio nondetections place a limit on the mass-loss rate from the putative companion that rules out a red giant but allows a main-sequence star. We discuss our results in the context of other similar SNe Ia in the literature. Copyright © 2023, The Authors. All rights reserved.

关键词： Detonation

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HIP 33609 b: An Eccentric Brown Dwarf Transiting a V=7.3 Rapidly Rotating B-Star

arXiv

引用

arXiv 2023年

作者： Vowell, Noah Rodriguez, Joseph E. Quinn, Samuel N. Zhou, George Vanderburg, Andrew Mann, Andrew W. Hooton, Matthew J. Stassun, Keivan G. Howard, Saburo Bieryla, Allyson Latham, David W. Howell, Steve B. Guillot, Tristan Ziegler, Carl Collins, Karen A. Carmichael, Theron W. Jenkins, Jon M. Shporer, Avi Abe, Lyu Bendjoya, Philippe Bush, Jonathan L. Buttu, Marco Collins, Kevin I. Eastman, Jason D. Fields, Matthew J. Gasparetto, Thomas Günther, Maximilian N. Kostov, Veselin B. Kraus, Adam L. Lester, Kathryn V. Levine, Alan M. Littlefield, Colin Marie-Sainte, Wenceslas Mékarnia, Djamel Osborn, Hugh P. Rapetti, David Ricker, George R. Seager, S. Srdoc, Gregor Suarez, Olga Torres, Guillermo Triaud, Amaury H.M.J. Vanderspek, R. Winn, Joshua N. Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48824 United States Center for Astrophysics | Harvard & Smithsonian 60 Garden St CambridgeMA02138 United States University of Southern Queensland West St Darling HeightsQLD4350 Australia Department of Physics Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology CambridgeMA02139 United States Department of Physics and Astronomy The University of North Carolina at Chapel Hill Chapel HillNC27599 United States Cavendish Laboratory JJ Thomson Avenue CambridgeCB3 0HE United Kingdom Department of Physics and Astronomy Vanderbilt University NashvilleTN37235 United States Department of Physics Fisk University 1000 17th Avenue North NashvilleTN37208 United States Université Côte d’Azur Observatoire de la Côte d’Azur CNRS Lagrange Laboratory Nice France NASA Ames Research Center Moffett FieldCA94035 United States Department of Physics Engineering and Astronomy Stephen F. Austin State University 1936 North St NacogdochesTX75962 United States Institute for Astronomy University of Edinburgh Royal Observatory Blackford Hill EdinburghEH9 3HJ United Kingdom INAF - Osservatorio Astronomico di Cagliari Cagliari Italy George Mason University 4400 University Drive FairfaxVA22030 United States Institute of Polar Sciences CNR via Torino 155 Venice-Mestre30172 Italy Keplerlaan 1 Noordwijk2201 AZ Netherlands NASA Goddard Space Flight Center 8800 Greenbelt Road GreenbeltMD20771 United States SETI Institute 189 Bernardo Ave Suite 200 Mountain ViewCA94043 United States Department of Astronomy The University of Texas at Austin AustinTX78712 United States Bay Area Environmental Research Institute Moffett FieldCA94035 United States Institut Paul Emile Victor Concordia Station Antarctica Physikalisches Institut University of Bern Gesellsschaftstrasse 6 Bern3012 Switzerland Re

We present the discovery and characterization of HIP 33609 b, a transiting warm brown dwarf orbiting a late B-star, discovered by NASA’s Transiting Exoplanet Survey Satellite (TESS) as TOI-588 b. HIP 33609 b is a large (Rb = 1.580+0.074-0.070 RJ) brown dwarf on a highly eccentric (e = 0.560+0.029-0.031) orbit with a 39-day period. The host star is a bright (V = 7.3 mag), Teff = 10,400+800-660 K star with a mass of M∗= 2.383+0.10-0.095 Mo and radius of R∗= 1.863+0.087-0.082 Ro, making it the hottest transiting brown dwarf host star discovered to date. We obtained radial velocity measurements from the CHIRON spectrograph confirming the companion’s mass of Mb = 68.0+7.4-7.1 MJ as well as the host star’s rotation rate (vsini∗ = 55.6 ±1.8 km/s). We also present the discovery of a new comoving group of stars, designated as MELANGE-6, and determine that HIP 33609 is a member. We use a combination of rotation periods and isochrone models fit to the cluster members to estimate an age of 150 ± 25 Myr. With a measured mass, radius, and age, HIP 33609 b becomes a benchmark for substellar evolutionary models. Copyright © 2023, The Authors. All rights reserved.

关键词： Orbits

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Three Saturn-mass planets transiting F-type stars revealed with TESS and HARPS

arXiv

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arXiv 2023年

作者： Psaridi, Angelica Bouchy, François Lendl, Monika Akinsanmi, Babatunde Stassun, Keivan G. Smalley, Barry Armstrong, David J. Howard, Saburo Ulmer-Moll, Solène Grieves, Nolan Barkaoui, Khalid Rodriguez, Joseph E. Bryant, Edward M. Suárez, Olga Guillot, Tristan Evans, Phil Attia, Omar Wittenmyer, Robert A. Yee, Samuel W. Collins, Karen A. Zhou, George Galland, Franck Parc, Léna Udry, Stéphane Figueira, Pedro Ziegler, Carl Mordasini, Christoph Winn, Joshua N. Seager, Sara Jenkins, Jon M. Twicken, Joseph D. Brahm, Rafael Jones, Matías I. Abe, Lyu Addison, Brett Briceño, César Briegal, Joshua T. Collins, Kevin I. Daylan, Tansu Eigmüller, Phillip Furesz, Gabor Guerrero, Natalia M. Hagelberg, Janis Heitzmann, Alexis Hounsell, Rebekah Huang, Chelsea X. Krenn, Andreas Law, Nicholas M. Mann, Andrew W. McCormac, James Mékarnia, Djamel Mounzer, Dany Nielsen, Louise D. Osborn, Ares Reinarz, Yared Sefako, Ramotholo R. Steiner, Michal Strøm, Paul A. Triaud, Amaury H.M.J. Vanderspek, Roland Vanzi, Leonardo Vines, Jose I. Watson, Christopher A. Wright, Duncan J. Zapata, Abner Observatoire de Genève Université de Genève Chemin Pegasi 51 Versoix1290 Switzerland Vanderbilt University Department of Physics & Astronomy 6301 Stevenson Center Lane NashvilleTN37235 United States Astrophysics Group Keele University StaffordshireST5 5BG United Kingdom Department of Physics University of Warwick Gibbet Hill Road CoventryCV4 7AL United Kingdom Centre for Exoplanets and Habitability University of Warwick Gibbet Hill Road CoventryCV4 7AL United Kingdom Université Côte d’Azur Observatoire de la Côte d’Azur CNRS Laboratoire Lagrange Bd de l’Observatoire CS 34229 Nicecedex 4 06304 France Physikalisches Institut University of Bern Gesellschaftsstrasse 6 Bern3012 Switzerland Astrobiology Research Unit Université de Liège 19C Allée du 6 Août Liège4000 Belgium Department of Earth Atmospheric and Planetary Science Massachusetts Institute of Technology 77 Massachusetts Avenue CambridgeMA02139 United States Calle Vía Láctea s/n Tenerife La Laguna38200 Spain Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48824 United States Mullard Space Science Laboratory University College London Holmbury St Mary Surrey DorkingRH5 6NT United Kingdom El Sauce Observatory Coquimbo Province Chile University of Southern Queensland Centre for Astrophysics West Street ToowoombaQLD4350 Australia Department of Astrophysical Sciences Princeton University PrincetonNJ08544 United States Center for Astrophysics | Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States University of Grenoble Alpes CNRS IPAG GrenobleF-38000 France Instituto de Astrofísica e Ciências do Espaço Universidade do Porto CauP Rua das Estrelas Porto4150-762 Portugal Department of Physics Engineering and Astronomy Stephen F. Austin State University 1936 North St NacogdochesTX75962 United States Department of Physics Kavli Institute for Astrophysics and Space Research

While the sample of confirmed exoplanets continues to grow, the population of transiting exoplanets around early-type stars is still limited. These planets allow us to investigate the planet properties and formation pathways over a wide range of stellar masses and study the impact of high irradiation on hot Jupiters orbiting such stars. We report the discovery of TOI-615b, TOI-622b, and TOI-2641b, three Saturn-mass planets transiting main sequence, F-type stars. The planets were identified by the Transiting Exoplanet Survey Satellite (TESS) and confirmed with complementary ground-based and radial velocity observations. TOI-615b is a highly irradiated (∼1277 F⊕) and bloated Saturn-mass planet (formula presented) in a 4.66 day orbit transiting a 6850 K star. TOI-622b has a radius of (formula presented) RJup and a mass of (formula presented) in a 6.40 day orbit. Despite its high insolation flux (∼600 F⊕), TOI-622b does not show any evidence of radius inflation. TOI-2641b is a (formula presented) planet in a 4.88 day orbit with a grazing transit (formula presented) that results in a poorly constrained radius of (formula presented). Additionally, TOI-615b is considered attractive for atmospheric studies via transmission spectroscopy with ground-based spectrographs and JWST. Future atmospheric and spin-orbit alignment observations are essential since they can provide information on the atmospheric composition, formation, and migration of exoplanets across various stellar types. © 2023, CC BY.

关键词： Stars

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Streams, Shells, and Substructures in the Accretion-Built Stellar Halo of NGC 300

arXiv

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arXiv 2025年

作者： Fielder, Catherine E. Sand, David J. Jones, Michael G. Crnojević, Denija Drlica-Wagner, Alex Bennet, Paul Carlin, Jeffrey L. Cerny, William Doliva-Dolinsky, Amandine Hunter, Laura C. Karunakaran, Ananthan Limberg, Guilherme Mutlu-Pakdil, Burçin Pace, Andrew B. Pearson, Sarah Smercina, Adam Spekkens, Kristine Starkenburg, Tjitske Strader, Jay Stringfellow, Guy S. Tollerud, Erik Bom, Clecio R. Carballo-Bello, Julio A. Chaturvedi, Astha Choi, Yumi James, David J. Martínez-Vázquez, Clara E. Riley, Alex Sakowska, Joanna Vivas, Kathy Steward Observatory University of Arizona 933 North Cherry Avenue TucsonAZ85721-0065 United States Department of Physics and Astronomy University of Tampa 401 West Kennedy Boulevard TampaFL33606 United States Astronomy & Astrophysics University of Chicago ChicagoIL60637 United States Fermi National Accelerator Laboratory BataviaIL United States Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States AURA/Rubin Observatory 950 North Cherry Avenue TucsonAZ85719 United States Department of Astronomy Yale University New HavenCT06520 United States Department of Physics and Astronomy Dartmouth College HanoverNH03755 United States Department of Astronomy & Astrophysics University of Toronto TorontoONM5S 3H4 Canada Dunlap Institute for Astronomy and Astrophysics University of Toronto TorontoONM5S 3H4 Canada Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States Department of Astronomy University of Virginia 530 McCormick Rd CharlottesvilleVA22904 United States Niels Bohr Institute University of Copenhagen Copenhagen Denmark Department of Physics and Space Science Royal Military College of Canada P.O. Box 17000 Station Forces KingstonONK7K 7B4 Canada Department of Physics Engineering Physics and Astronomy Queen's University KingstonONK7L 3N6 Canada Department of Physics & Astronomy CIERA Northwestern University EvanstonIL United States Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48824 United States Center for Astrophysics and Space Astronomy University of Colorado 389 UCB BoulderCO80309-0389 United States Centro Brasileiro de Pesquisas Fisicas Rua Dr. Xavier Sigaud 150 RJ Rio de Janeiro22290-180 Brazil Instituto de Alta Investigación Universidad de Tarapacá Casilla 7D Arica Chile Department of Physics University of Surrey GuildfordGU2 7XH United Kingdom NSF NOIRLab 95

We present deep optical observations of the stellar halo of NGC 300, an LMC-mass galaxy, acquired with the DEEP sub-component of the DECam Local Volume Exploration survey (DELVE) using the 4 m Blanco Telescope. Our resolved star analysis reveals a large, low surface brightness stellar stream (MV ∼ -8.5;[Fe/H] = -1.4± 0.15) extending more than 40 kpc north from the galaxy's center. We also find other halo structures, including potentially an additional stream wrap to the south, which may be associated with the main stream. The morphology and derived low metallicities of the streams and shells discovered surrounding NGC 300 are highly suggestive of a past accretion event. Assuming a single progenitor, the accreted system is approximately Fornax-like in luminosity, with an inferred mass ratio to NGC 300 of approximately 1 : 15. We also present the discovery of a metal-poor globular cluster (Rproj = 23.3 kpc;MV = -8.99± 0.16;[Fe/H] ≈ -1.6± 0.6) in the halo of NGC 300, the furthest identified globular cluster associated with NGC 300. The stellar structures around NGC 300 represent the richest features observed in a Magellanic Cloud analog to date, strongly supporting the idea that accretion and subsequent disruption is an important mechanism in the assembly of dwarf galaxy stellar halos. © 2025, CC BY-SA.

关键词： Stars

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Classical novae at radio wavelengths

arXiv

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arXiv 2021年

作者： Chomiuk, Laura Linford, Justin D. Aydi, Elias Bannister, Keith W. Krauss, Miriam I. Mioduszewski, Amy J. Mukai, Koji Nelson, Thomas J. Rupen, Michael P. Ryder, Stuart D. Sokoloski, Jennifer L. Sokolovsky, Kirill V. Strader, Jay Filipović, Miroslav D. Finzell, Tom Kawash, Adam Kool, Erik C. Metzger, Brian D. Nyamai, Miriam M. Ribeiro, Valério A.R.M. Roy, Nirupam Urquhart, Ryan Weston, Jennifer Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48824 United States National Radio Astronomy Observatory P.O. Box O SocorroNM87801 United States CSIRO Astronomy and Space Science PO Box 76 EppingNSW1710 Australia Pasadena City College 1570 E. Colorado Blvd. PasadenaCA91106 United States Center for Space Science and Technology University of Maryland Baltimore County BaltimoreMD21250 United States CRESST and X-ray Astrophysics Laboratory NASA/GSFC GreenbeltMD20771 United States Department of Physics and Astronomy University of Pittsburgh 3941 OHara St. PittsburghPA15260 United States Herzberg Institute of Astrophysics National Research Council of Canada PentictonBCV2A 6J9 Canada Department of Physics and Astronomy Macquarie University NSW2109 Australia Macquarie University Research Centre for Astronomy Astrophysics & Astrophotonics SydneyNSW2109 Australia Columbia Astrophysics Laboratory Columbia University New YorkNY United States Sternberg Astronomical Institute Moscow State University Universitetskii pr. 13 Moscow119992 Russia Western Sydney University Locked Bag 1797 Penrith South DCNSW2751 Australia Department of Computational Math Science and Engineering Michigan State University East LansingMI48824 United States The Oskar Klein Centre Department of Astronomy Stockholm University AlbaNova StockholmSE-106 91 Sweden Center for Computational Astrophysics Flatiron Institute 162 W. 5th Avenue New YorkNY10011 United States Department of Astronomy University of Cape Town Private Bag X3 Rondebosch7701 South Africa Instituto de Telecomunicações Campus Universitário de Santiago Aveiro3810-193 Portugal Department of Physics Indian Institute of Science Bangalore560012 India Federated IT 1201 Wilson Blvd 27th Floor ArlingtonVA22209 United States

We present radio observations (1–40 GHz) for 36 classical novae, representing data from over five decades compiled from the literature, telescope archives, and our own programs. Our targets display a striking diversity in their optical parameters (e.g., spanning optical fading timescales, t2 = 1–263 days), and we find a similar diversity in the radio light curves. Using a brightness temperature analysis, we find that radio emission from novae is a mixture of thermal and synchrotron emission, with non-thermal emission observed at earlier times. We identify high brightness temperature emission (TB > 5 × 104 K) as an indication of synchrotron emission in at least 9 (25%) of the novae. We find a class of synchrotron-dominated novae with mildly evolved companions, exemplified by V5589 Sgr and V392 Per, that appear to be a bridge between classical novae with dwarf companions and symbiotic binaries with giant companions. Four of the novae in our sample have two distinct radio maxima (the first dominated by synchrotron and the later by thermal emission), and in four cases the early synchrotron peak is temporally coincident with a dramatic dip in the optical light curve, hinting at a common site for particle acceleration and dust formation. We publish the light curves as tables and encourage use of these data by the broader community in multi-wavelength studies and modeling efforts. © 2021, CC BY.

关键词： Radio astronomy

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On the generalization of DIRECTFN for singular integrals over quadrilateral patches

arXiv

引用

arXiv 2017年

作者： Tambova, Alexandra Litsarev, Mikhail Guryev, Georgy Polimeridis, Athanasios G. Center for Computational Data-Intensive Science and Engineering Skoltech Moscow Russia

A set of fully numerical algorithms for evaluating the four-dimensional singular integrals arising from Galerkin surface integral equation methods over conforming quadrilateral meshes is presented. This work is an extension of DIRECTFN, which was recently developed for the case of triangular patches, utilizing in a same fashion a series of coordinate transformations together with appropriate integration re-orderings. The resulting formulas consist of sufficiently smooth kernels and exhibit several favorable characteristics when compared with the vast majority of the methods currently available. More specifically, they can be applied-without modifications-to the following challenging cases: 1) weakly and strongly singular kernels, 2) basis and testing functions of arbitrary order, 3) planar and curvilinear patches, 4) problem-specific Green functions (e.g. expressed in spectral integral form), 5) spectral convergence to machine precision. Finally, we show that the overall performance of the fully numerical schemes can be further improved by a judicious choice of the integration order for each dimension. Copyright © 2017, The Authors. All rights reserved.

关键词： Galerkin methods

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Young, blue, and isolated stellar systems in the Virgo Cluster. II. A new class of stellar system

arXiv

引用

arXiv 2022年

作者： Jones, Michael G. Sand, David J. Bellazzini, Michele Spekkens, Kristine Karunakaran, Ananthan Adams, Elizabeth A.K. Battaglia, Giuseppina Beccari, Giacomo Bennet, Paul Cannon, John M. Cresci, Giovanni Crnojević, Denija Caldwell, Nelson Fuson, Jackson Guhathakurta, Puragra Haynes, Martha P. Inoue, John L. Magrini, Laura Muñoz, Ricardo R. Mutlu-Pakdil, Burçin Seth, Anil Strader, Jay Toloba, Elisa Zaritsky, Dennis Steward Observatory University of Arizona 933 North Cherry Avenue Rm. N204 TucsonAZ85721-0065 United States INAF - Osservatorio di Astrofisica e Scienza dello Spazio di Bologna Via Gobetti 93/3 Bologna40129 Italy Department of Physics and Space Science Royal Military College of Canada P.O. Box 17000 Station Forces Kingston ONK7K 7B4 Canada Department of Physics Engineering Physics and Astronomy Queen's University KingstonONK7L 3N6 Canada Glorieta de la Astronomía Granada18008 Spain ASTRON The Netherlands Institute for Radio Astronomy Oude Hoogeveesedijk 4 Dwingeloo 7991 PD Netherlands Kapteyn Astronomical Institute PO Box 800 Groningen9700 AV Netherlands Instituto de Astrofísica de Canarias Vía Láctea s/n La Laguna 38205 Spain Universidad de La Laguna Avda. Astrofísico Fco. Sánchez Tenerife La LagunaE-38205 Spain European Southern Observatory Karl-Schwarzschild-Strasse 2 Garching bei München D-85748 Germany Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States Department of Physics & Astronomy Macalester College 1600 Grand Avenue Saint PaulMN55105 United States INAF - Osservatorio Astrofisico di Arcetri Largo E. Fermi 5 Firenze50125 Italy University of Tampa 401 West Kennedy Boulevard TampaFL33606 United States Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States UCO/Lick Observatory University of California Santa Cruz 1156 High Street Santa CruzCA95064 United States Cornell Center for Astrophysics and Planetary Science Space Sciences Building Cornell University IthacaNY14853 United States Departamento de Astronomía Universidad de Chile Camino El Observatorio 1515 Las Condes Santiago Chile Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States Department of Astronomy and Astrophysics University of Chicago ChicagoIL60637 United States Department of Physics & Astronomy University of Utah Salt Lake City

We discuss five blue stellar systems in the direction of the Virgo cluster, analogous to the enigmatic object SECCO 1 (AGC 226067). These objects were identified based on their optical and UV morpholog☉y and followed up with H i observations with the VLA (and GBT), MUSE/VLT optical spectroscopy, and HST imaging. These new data indicate that one system is a distant group of galaxies. The remaining four are extremely low mass (M∗ ∼ 105 M☉), are dominated by young, blue stars, have highly irregular and clumpy morphologies, are only a few kpc across, yet host an abundance of metal-rich, 12 + log(O/H) > 8.2, H ii regions. These high metallicities indicate that these stellar systems formed from gas stripped from much more massive galaxies. Despite the young age of their stellar populations, only one system is detected in H i, while the remaining three have minimal (if any) gas reservoirs. Furthermore, two systems are surprisingly isolated and have no plausible parent galaxy within ∼30' (∼140 kpc). Although tidal stripping cannot be conclusively excluded as the formation mechanism of these objects, ram pressure stripping more naturally explains their properties, in particular their isolation, owing to the higher velocities, relative to the parent system, that can be achieved. Therefore, we posit that most of these systems formed from ram pressure stripped gas removed from new infalling cluster members, and survived in the intracluster medium long enough to become separated from their parent galaxies by hundreds of kiloparsecs, and that they thus represent a new type of stellar system. © 2022, CC BY.

关键词： Galaxies

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Constraining the Progenitor System of the Type Ia Supernova 2021aefx

arXiv

引用

arXiv 2022年

作者： Hosseinzadeh, Griffin Sand, David J. Lundqvist, Peter Andrews, Jennifer E. Bostroem, K. Azalee Dong, Yize Janzen, Daryl Jencson, Jacob E. Lundquist, Michael Retamal, Nicolas E. Meza Pearson, Jeniveve Valenti, Stefano Wyatt, Samuel Burke, Jamison Howell, D. Andrew McCully, Curtis Newsome, Megan Gonzalez, Estefania Padilla Pellegrino, Craig Terreran, Giacomo Kwok, Lindsey A. Jha, Saurabh W. Strader, Jay Kundu, Esha Ryder, Stuart D. Haislip, Joshua Kouprianov, Vladimir Reichart, Daniel E. Steward Observatory University of Arizona 933 North Cherry Avenue TucsonAZ85721-0065 United States Oskar Klein Centre Department of Astronomy Stockholm University Albanova University Centre StockholmSE-106 91 Sweden Gemini Observatory 670 North A'ohoku Place HiloHI96720-2700 United States Department of Astronomy University of Washington 3910 15th Avenue NE SeattleWA98195-0002 United States Department of Physics and Astronomy University of California Davis 1 Shields Avenue DavisCA95616-5270 United States Department of Physics & Engineering Physics University of Saskatchewan 116 Science Place SaskatoonSKS7N 5E2 Canada W. M. Keck Observatory 65-1120 Mamalahoa Highway KamuelaHI96743-8431 United States Las Cumbres Observatory 6740 Cortona Drive GoletaCA93117-5575 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Department of Physics and Astronomy Rutgers the State University of New Jersey 136 Frelinghuysen Road PiscatawayNJ08854-8019 United States Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48824 United States School of Mathematical and Physical Sciences Macquarie University NSW2109 Australia Astronomy Astrophysics and Astrophotonics Research Centre Macquarie University SydneyNSW2109 Australia Department of Physics and Astronomy University of North Carolina 120 East Cameron Avenue Chapel HillNC27599 United States

We present high-cadence optical and ultraviolet light curves of the normal Type Ia supernova (SN) 2021aefx, which shows an early bump during the first two days of observation. This bump may be a signature of interaction between the exploding white dwarf and a nondegenerate binary companion, or it may be intrinsic to the white dwarf explosion mechanism. In the case of the former, the short duration of the bump implies a relatively compact main-sequence companion star, although this conclusion is viewing-angle dependent. Our best-fit companion-shocking and double-detonation models both overpredict the UV luminosity during the bump, and existing nickel-shell models do not match the strength and timescale of the bump. We also present nebular spectra of SN 2021aefx, which do not show the hydrogen or helium emission expected from a nondegenerate companion, as well as a radio nondetection that rules out all symbiotic progenitor systems and most accretion disk winds. Our analysis places strong but conflicting constraints on the progenitor of SN 2021aefx;no current model can explain all of our observations. Copyright © 2022, The Authors. All rights reserved.

关键词： Supernovae

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