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arXiv 2023年

作者： Wagner, Kevin Stone, Jordan Skemer, Andrew Ertel, Steve Dong, Ruobing Apai, Dániel Spalding, Eckhart Leisenring, Jarron Sitko, Michael Kratter, Kaitlin Barman, Travis Marley, Mark Miles, Brittany Boccaletti, Anthony Assani, Korash Bayyari, Ammar Uyama, Taichi Woodward, Charles E. Hinz, Phil Briesemeister, Zackery Lawson, Kellen Ménard, François Pantin, Eric Russell, Ray W. Skrutskie, Michael Wisniewski, John Department of Astronomy Steward Observatory University of Arizona 933 N Cherry Ave TucsonAZ85721 United States Naval Research Laboratory 4555 Overlook Ave SW WashingtonDC20375 United States Department of Astronomy & Astrophysics University of California Santa Cruz 1156 High Street Santa CruzCA95064 United States Department of Physics and Astronomy University of Victoria 3800 Finnerty Road VictoriaBCV8P 5C2 Canada Lunar and Planetary Laboratory Dept. of Planetary Sciences University of Arizona 1629 E University Blvd TucsonAZ85721 United States The University of Sydney NSW2006 Australia Space Science Institute 4765 Walnut St STE B BoulderCO80301 United States Observatoire de Paris-PSL CNRS 5 place Jules Janssen Meudon92195 France Department of Astronomy University of Virginia 530 McCormick Rd CharlottesvilleVA22904 United States Department of Physics and Astronomy University of Hawaii 2505 Correa Road Watanabe 416 HonoluluHI96822 United States Infrared Processing and Analysis Center California Institute of Technology 1200 E. California Blvd. PasadenaCA91125 United States NASA Exoplanet Science Institute PasadenaCA91125 United States National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Minnesota Institute for Astrophysics University of Minnesota 116 Church Street SE MinneapolisMN55455 United States Homer L. Dodge Department of Physics and Astronomy The University of Oklahoma 440 W. Brooks St. NormanOK73019 United States Univ. Grenoble Alpes CNRS IPAG GrenobleF-38000 France Département d’Astrophysique CE Saclay Orme des Merisiers Bât 709 Gif-sur-Yvette91191 France The Aerospace Corporation 2310 E. El Segundo Blvd El SegundoCA90245 United States NASA Headquarters 300 Hidden Figures Way SW WashingtonDC20546 United States NASA Hubble Fellowship Program Sagan Fellow United States

Understanding the driving forces behind spiral arms in protoplanetary disks remains a challenge due to the faintness of young giant planets. MWC 758 hosts such a protoplanetary disk with a two-armed spiral pattern that is suggested to be driven by an external giant planet. We present new thermal infrared observations that are uniquely sensitive to redder (i.e., colder or more attenuated) planets than past observations at shorter wavelengths. We detect a giant protoplanet, MWC 758c, at a projected separation of ~100 au from the star. The spectrum of MWC 758c is distinct from the rest of the disk and consistent with emission from a planetary atmosphere with Teff = 500 ± 100 K for a low level of extinction (AV≤30), or a hotter object with a higher level of extinction. Both scenarios are commensurate with the predicted properties of the companion responsible for driving the spiral arms. MWC 758c provides evidence that spiral arms in protoplanetary disks can be caused by cold giant planets or by those whose optical emission is highly attenuated. MWC 758c stands out both as one of the youngest giant planets known, and also as one of the coldest and/or most attenuated. Furthermore, MWC 758c is among the first planets to be observed within a system hosting a protoplanetary disk. © 2023, CC BY.

关键词： Planets

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A candidate electromagnetic counterpart to the binary black hole merger gravitational wave event S190521g

arXiv

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arXiv 2020年

作者： Graham, M.J. Ford, K.E.S. McKernan, B. Ross, N.P. Stern, D. Burdge, K. Coughlin, M. Djorgovski, S.G. Drake, A.J. Duev, D. Kasliwal, M. Mahabal, A.A. van Velzen, S. Belecki, J. Bellm, E.C. Burruss, R. Cenko, S.B. Cunningham, V. Helou, G. Kulkarni, S.R. Masci, F.J. Prince, T. Reiley, D. Rodriguez, H. Rusholme, B. Smith, R.M. Soumagnac, M.T. Cahill Center for Astronomy & Astrophysics California Institute of Technology 1200 E. California Blvd. PasadenaCA91125 United States Department of Science CUNY-BMCC 199 Chambers St. New YorkNY10007 United States Department of Astrophysics American Museum of Natural History Central Park West New YorkNY10028 United States Physics Program Graduate Center CUNY New YorkNY10016 United States Institute for Astronomy University of Edinburgh Royal Observatory Blackford Hill EdinburghEH9 3 HJ United Kingdom Jet Propulsion Laboratory California Institute of Technology PasadenaCA91109 United States Division of Physics Mathematics and Astronomy California Institute of Technology PasadenaCA91125 United States School of Physics and Astronomy University of Minnesota MinneapolisMN55455 United States Department of Astronomy University of Maryland College ParkMD20742 United States Center for Cosmology and Particle Physics New York University NY10003 United States Caltech Optical Observatories California Institute of Technology PasadenaCA91125 United States DIRAC Institute Department of Astronomy University of Washington 3910 15th Ave. NE SeattleWA98195 United States Astrophysics Science Division NASA Goddard Space Flight Center MC 661 GreenbeltMD20771 United States Joint Space-Science Institute University of Maryland College ParkMD20742 United States IPAC California Institute of Technology 1200 E. California Blvd PasadenaCA91125 United States IPAC California Institute of Technology 1200 E. California Blvd. PasadenaCA91125 United States Lawrence Berkeley National Laboratory 1 Cyclotron Road BerkeleyCA94720 United States Department of Particle Physics and Astrophysics Weizmann Institute of Science Rehovot76100 Israel

We report the first plausible optical electromagnetic (EM) counterpart to a (candidate) binary black hole (BBH) merger. Detected by the Zwicky Transient Facility (ZTF), the EM flare is consistent with expectations for a kicked BBH merger in the accretion disk of an active galactic nucleus (AGN) [1], and is unlikely (☉, kick velocity vk ∼ 200 km s−1 at θ ∼ 60◦ in a disk with aspect ratio H/a ∼ 0.01 (i.e., disk height H at radius a) and gas density ρ ∼ 10−10 g cm−3. The merger could have occurred at a disk migration trap (a ∼ 700 rg;rg ≡ GMSMBH/c2, where MSMBH is the mass of the AGN supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a re-encountering with the disk in ∼ 1.6 yr (MSMBH/108M☉) (a/103rg)3/2. Copyright © 2020, The Authors. All rights reserved.

关键词： Merging

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First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

arXiv

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arXiv 2023年

作者： Akiyama, Kazunori Alberdi, Antxon Alef, Walter Algaba, Juan Carlos Anantua, Richard Asada, Keiichi Azulay, Rebecca Bach, Uwe Baczko, Anne-Kathrin Ball, David Baloković, Mislav Barrett, John Bauböck, Michi Benson, Bradford A. Bintley, Dan Blackburn, Lindy Blundell, Raymond Bouman, Katherine L. Bower, Geoffrey C. Boyce, Hope Bremer, Michael Brinkerink, Christiaan D. Brissenden, Roger Britzen, Silke Broderick, Avery E. Broguiere, Dominique Bronzwaer, Thomas Bustamante, Sandra Byun, Do-Young Carlstrom, John E. Ceccobello, Chiara Chael, Andrew Chan, Chi-Kwan Chatterjee, Koushik Chatterjee, Shami Chen, Ming-Tang Chen, Yongjun Cheng, Xiaopeng Cho, Ilje Christian, Pierre Conroy, Nicholas S. Conway, John E. Cordes, James M. Crawford, Thomas M. Crew, Geoffrey B. Cruz-Osorio, Alejandro Cui, Yuzhu Davelaar, Jordy De Laurentis, Mariafelicia Deane, Roger Dempsey, Jessica Desvignes, Gregory Dexter, Jason Dhruv, Vedant Doeleman, Sheperd S. Dougal, Sean Dzib, Sergio A. Eatough, Ralph P. Emami, Razieh Falcke, Heino Farah, Joseph Fish, Vincent L. Fomalont, Ed Ford, H. Alyson Fraga-Encinas, Raquel Freeman, William T. Friberg, Per Fromm, Christian M. Fuentes, Antonio Galison, Peter Gammie, Charles F. García, Roberto Gentaz, Olivier Georgiev, Boris Goddi, Ciriaco Gold, Roman Gómez-Ruiz, Arturo I. Gómez, José L. Gu, Minfeng Gurwell, Mark Hada, Kazuhiro Haggard, Daryl Haworth, Kari Hecht, Michael H. Hesper, Ronald Heumann, Dirk Ho, Luis C. Ho, Paul Honma, Mareki Huang, Chih-Wei L. Huang, Lei Hughes, David H. Ikeda, Shiro Impellizzeri, C.M. Violette Inoue, Makoto Issaoun, Sara James, David J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton Jiang, Wu Jiménez-Rosales, Alejandra Johnson, Michael D. Jorstad, Svetlana Joshi, Abhishek V. Jung, Taehyun Karami, Mansour Karuppusamy, Ramesh Kawashima, Tomohisa Keating, Garrett K. Kettenis, Mark Kim, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kino, Motoki Koay, Jun Yi Kocherlakota, Prashant Kofuji, Yutaro Koch, Patrick M. Koyama, Shoko Kramer, Carsten Kramer, Michael Krichbaum, Thomas P. Ku Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road WestfordMA01886 United States National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Black Hole Initiative Harvard University 20 Garden Street CambridgeMA02138 United States Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n GranadaE-18008 Spain Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Department of Physics Faculty of Science Universiti Malaya Kuala Lumpur50603 Malaysia Center for Astrophysics | Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Department of Physics & Astronomy The University of Texas at San Antonio One UTSA Circle San AntonioTX78249 United States Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan Departament d'Astronomia i Astrofísica Universitat de València C. Dr. Moliner 50 Burjassot ValènciaE-46100 Spain Observatori Astronòmic Universitat de València C. Catedrático José Beltrán 2 Paterna ValènciaE-46980 Spain Steward Observatory Department of Astronomy University of Arizona 933 N. Cherry Ave. TucsonAZ85721 United States Yale Center for Astronomy & Astrophysics Yale University 52 Hillhouse Avenue New HavenCT06511 United States Department of Physics University of Illinois 1110 West Green Street UrbanaIL61801 United States Fermi National Accelerator Laboratory MS209 P.O. Box 500 BataviaIL60510 United States Department of Astronomy and Astrophysics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States East Asian Observatory 660 N. A'ohoku Place HiloHI96720 United States 660 N. A'ohoku Place HiloHI96720 United States California Institute of Technology 1200 East California Boulevard PasadenaCA91125 United States Institute of Astronomy and Astrophysics Academia Sinica 645 N. A'ohoku Place HiloHI

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A∗), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength of λ = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of 51.8 ± 2.3 µas (68% credible interval). The ring has modest azimuthal brightness asymmetry and a comparatively dim interior. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A∗ are consistent with the expected appearance of a Kerr black hole with mass ∼4 × 106 M☉, which is inferred to exist at this location based on previous infrared observations of individual stellar orbits as well as maser proper motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50◦), as well as non-spinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way galaxy, and for the first time we connect the predictions from dynamical measurements of stellar orbits on scales of 103 − 105 gravitational radii to event horizon-scale images and variability. Furthermore, a comparison with the EHT results for the supermassive black hole M87∗ shows consistency with the predictions of general relativity spanning over three orders of magnitude in central mass. © 2023, CC BY.

关键词： Telescopes

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Third data release of the hyper suprime-cam subaru strategic program

arXiv

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arXiv 2021年

作者： Aihara, Hiroaki AlSayyad, Yusra Ando, Makoto Armstrong, Robert Bosch, James Egami, Eiichi Furusawa, Hisanori Furusawa, Junko Harasawa, Sumiko Harikane, Yuichi Hsieh, Bau-Ching Ikeda, Hiroyuki Ito, Kei Iwata, Ikuru Kodama, Tadayuki Koike, Michitaro Kokubo, Mitsuru Komiyama, Yutaka Li, Xiangchong Liang, Yongming Lin, Yen-Ting Lupton, Robert H. Lust, Nate B. MacArthur, Lauren A. Mawatari, Ken Mineo, Sogo Miyatake, Hironao Miyazaki, Satoshi More, Surhud Morishima, Takahiro Murayama, Hitoshi Nakajima, Kimihiko Nakata, Fumiaki Nishizawa, Atsushi J. Oguri, Masamune Okabe, Nobuhiro Okura, Yuki Ono, Yoshiaki Osato, Ken Ouchi, Masami Pan, Yen-Chen Malagón, Andrés A. Plazas Price, Paul A. Reed, Sophie L. Rykoff, Eli S. Shibuya, Takatoshi Simunovic, Mirko Strauss, Michael A. Sugimori, Kanako Suto, Yasushi Suzuki, Nao Takada, Masahiro Takagi, Yuhei Takata, Tadafumi Takita, Satoshi Tanaka, Masayuki Tang, Shenli Taranu, Dan S. Terai, Tsuyoshi Toba, Yoshiki Turner, Edwin L. Uchiyama, Hisakazu Vijarnwannaluk, Bovornpratch Waters, Christopher Z. Yamada, Yoshihiko Yamamoto, Naoaki Yamashita, Takuji Department of Physics The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan The University of Tokyo 5-1-5 Kashiwanoha Kashiwa Chiba277-8583 Japan Department of Astrophysical Sciences Princeton University 4 Ivy Lane PrincetonNJ08544 United States Department of Astronomy Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan Lawrence Livermore National Laboratory LivermoreCA94551 United States Steward Observatory The University of Arizona 933 North Cherry Avenue TucsonAZ85721-0065 United States National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwanoha Chiba Kashiwa277-8582 Japan Department of Physics and Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No.1 Sec. 4 Taipei10617 Taiwan National Institute of Technology Wakayama College 77 Noshima Nada-cho Gobo Wakayama644-0023 Japan Department of Astronomical Science The Graduate University for Advanced Studies SOKENDAI 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Astronomical Institute Tohoku University 6-3 Aramaki Aoba-ku Miyagi Sendai980-8578 Japan Nagoya University Nagoya464-8602 Japan Inter University Centre for Astronomy and Astrophysics Ganeshkhind Pune411007 India Department of Physics Center for Japanese Studies University of California BerkeleyCA94720 United States Theoretical Physics Group Lawrence Berkeley National Laboratory MS 50A-5104 BerkeleyCA94720 United States Institute for Advanced Research Nagoya University Furocho Chikusa-ku Nagoya464-8602 Japan Division of Particle and Astrophysical Science Graduate School of Science Nagoya University Furo-cho Nagoya464-8602 Japan Research Center for the Early Universe The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033

The paper presents the third data release of Hyper Suprime-Cam Subaru Strategic program (HSC-SSP), a wide-field multi-band imaging survey with the Subaru 8.2m telescope. HSC-SSP has three survey layers (Wide, Deep, and UltraDeep) with different area coverages and depths, designed to address a wide array of astrophysical questions. This third release from HSC-SSP includes data from 278 nights of observing time and covers about 670 square degrees in all five broad-band filters at the full depth (∼ 26 mag at 5σ) in the Wide layer. If we include partially observed area, the release covers 1,470 square degrees. The Deep and UltraDeep layers have ∼ 80% of the originally planned integration times, and are considered done, as we have slightly changed the observing strategy in order to compensate for various time losses. There are a number of updates in the image processing pipeline. Of particular importance is the change in the sky subtraction algorithm;we subtract the sky on small scales before the detection and measurement stages, which has significantly reduced false detections. Thanks to this and other updates, the overall quality of the processed data has improved since the previous release. However, there are limitations in the data (for example, the pipeline is not optimized for crowded fields), and we encourage the user to check the quality assurance plots as well as a list of known issues before exploiting the data. Copyright © 2021, The Authors. All rights reserved.

关键词： Surveys

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Incremental Fermi Large Area Telescope Fourth Source Catalog

arXiv

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arXiv 2022年

作者： Abdollahi, S. Acero, F. Baldini, L. Ballet, Jean Bastieri, D. Bellazzini, R. Berenji, B. Berretta, A. Bissaldi, E. Blandford, R.D. Bloom, E. Bonino, R. Brill, A. Britto, R.J. Bruel, P. Burnett, T.H. Buson, S. Cameron, R.A. Caputo, R. Caraveo, P.A. Castro, D. Chaty, S. Cheung, C.C. Chiaro, G. Cibrario, N. Ciprini, S. Coronado-Blázquez, J. Crnogorcevic, M. Cutini, S. D'Ammando, F. De Gaetano, S. Digel, S.W. Di Lalla, N. Dirirsa, F. Di Venere, L. Domínguez, A. Fallah Ramazani, V. Fegan, S.J. Ferrara, E.C. Fiori, A. Fleischhack, H. Franckowiak, A. Fukazawa, Y. Funk, S. Fusco, P. Galanti, G. Gammaldi, V. Gargano, F. Garrappa, S. Gasparrini, D. Giacchino, F. Giglietto, N. Giordano, F. Giroletti, M. Glanzman, T. Green, D. Grenier, I.A. Grondin, M.-H. Guillemot, L. Guiriec, S. Gustafsson, M. Harding, A.K. Hays, E. Hewitt, J.W. Horan, D. Hou, X. Jóhannesson, G. Karwin, C. Kayanoki, T. Kerr, M. Kuss, M. Landriu, D. Larsson, S. Latronico, L. Lemoine-Goumard, M. Li, J. Liodakis, I. Longo, F. Loparco, F. Lott, B. Lubrano, P. Maldera, S. Malyshev, D. Manfreda, A. Martí-Devesa, G. Mazziotta, M.N. Mereu, I. Meyer, M. Michelson, P.F. Mirabal, N. Mitthumsiri, W. Mizuno, T. Moiseev, A.A. Monzani, M.E. Morselli, A. Moskalenko, I.V. Negro, M. Nuss, E. Omodei, N. Orienti, M. Orlando, E. Paneque, D. Pei, Z. Perkins, J.S. Persic, M. Pesce-Rollins, M. Petrosian, V. Pillera, R. Poon, H. Porter, T.A. Principe, G. Rainò, S. Rando, R. Rani, B. Razzano, M. Razzaque, S. Reimer, A. Reimer, O. Reposeur, T. Sánchez-Conde, M. Saz Parkinson, P.M. Scotton, L. Serini, D. Sgrò, C. Siskind, E.J. Smith, D.A. Spandre, G. Spinelli, P. Sueoka, K. Suson, D.J. Tajima, H. Tak, D. Thayer, J.B. Thompson, D.J. Torres, D.F. Troja, E. Valverde, J. Wood, K. Zaharijas, G. IRAP Université de Toulouse CNRS UPS CNES ToulouseF-31028 France Université Paris Saclay Université Paris Cité CEA CNRS AIM Gif-sur-Yvette F-91191 France Università di Pisa Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova PadovaI-35131 Italy Dipartimento di Fisica e Astronomia "G. Galilei" Università di Padova PadovaI-35131 Italy Center for Space Studies and Activities "G. Colombo" University of Padova Via Venezia 15 PadovaI-35131 Italy Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy California State University Los Angeles Department of Physics and Astronomy Los AngelesCA90032 United States Dipartimento di Fisica Università degli Studi di Perugia PerugiaI-06123 Italy Dipartimento di Fisica "M. Merlin" Università e del Politecnico di Bari via Amendola 173 BariI-70126 Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari BariI-70126 Italy W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States Istituto Nazionale di Fisica Nucleare Sezione di Torino TorinoI-10125 Italy Dipartimento di Fisica Università degli Studi di Torino TorinoI-10125 Italy NASA Postdoctoral Program NASA Goddard Space Flight Center GreenbeltMD20771 United States Department of Physics University of the Free State P.O. Box 339 Bloemfontein9300 South Africa Laboratoire Leprince-Ringuet École Polytechnique CNRS IN2P3 PalaiseauF-91128 France Department of Physics University of Washington SeattleWA98195-1560 United States Institut für Theoretische Physik and Astrophysik Universität Würzburg WürzburgD-97074 Germany NASA Goddard Space Flight Center GreenbeltMD20771 United States INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano via E. Bassini 15 MilanoI-20133 Italy Harvard-Smithsoni

We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog of γ-ray sources. Based on the first twelve years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral parameterization for pulsars, and we extend the spectral points to 1 TeV. The spectral parameters, spectral energy distributions, and associations are updated for all sources. Light curves are rebuilt for all sources with 1 yr intervals (not 2 month intervals). Among the 5064 original 4FGL sources, 16 were deleted, 112 are formally below the detection threshold over 12 yr (but are kept in the list), while 74 are newly associated, 10 have an improved association, and seven associations were withdrawn. Pulsars are split explicitly between young and millisecond pulsars. Pulsars and binaries newly detected in LAT sources, as well as more than 100 newly classified blazars, are reported. We add three extended sources and 1607 new point sources, mostly just above the detection threshold, among which eight are considered identified, and 699 have a plausible counterpart at other wavelengths. We discuss the degree-scale residuals to the global sky model and clusters of soft unassociated point sources close to the Galactic plane, which are possibly related to limitations of the interstellar emission model and missing extended sources. © 2022, CC BY.

关键词： Pulsars

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Mars: New insights and unresolved questions

arXiv

引用

arXiv 2021年

作者： Changela, Hitesh G. Chatzitheodoridis, Elias Antunes, Andre Beaty, David Bouw, Kristian Bridges, John C. Capova, Klara Anna Cockell, Charles S. Conley, Catharine A. Dadachova, Ekaterina Dallas, Tiffany D. de Mey, Stefaan Dong, Chuanfei Ellery, Alex Ferus, Martin Foing, Bernard Fu, Xiaohui Fujita, Kazuhisa Lin, Yangtin Jheeta, Sohan Hicks, Leon J. Hu, Sen Kereszturi, Akos Krassakis, Alexandros Liu, Yang Oberst, Juergen Michalski, Joe Ranjith, P.M. Rinaldi, Teresa Rothery, David Stavrakakis, Hector A. Selbmann, Laura Sinha, Rishitosh K. Wang, Alian Williford, Ken Vaci, Zoltan Vago, Jorge L. Waltemathe, Michael Hallsworth, John E. Key Laboratory of Earth & Planetary Physics Institute of Geology & Geophysics Chinese Academy of Sciences Beijing China Department of Earth & Planetary Science University of New Mexico New Mexico United States Department of Geological Sciences National Technical University of Athens School of Mining and Metallurgical Engineering Athens Greece Network of Researchers on the Chemical Evolution of Life Leeds United Kingdom China Mars Program Office Jet Propulsion Laboratory California Institute of Technology PasadenaCA United States Creative Division Notion Theory MiamiFL33131 United States Space Research Centre School of Physics and Astronomy University of Leicester LeicesterLE17RH United Kingdom Noordwijk Netherlands School of Physics and Astronomy University of Edinburgh James Clerk Maxwell Building Peter Guthrie Tait Road EdinburghEH9 3FD United Kingdom NASA Ames Research Center Mountain ViewCA94035 United States College of Pharmacy and Nutrition University of Saskatchewan Canada Institute for Global Food Security School of Biological Sciences Queen's University Belfast 19 Chlorine Gardens BelfastBT9 5DL United Kingdom Department of Astrophysical Sciences Princeton Plasma Physics Laboratory Princeton University United States Department of Mechanical and Aerospace Engineering Carleton University OttawaON Canada J. Heyrovsky Institute of Physical Chemistry Czech Academy of Sciences Prague Czech Republic Shandong Province China Tokyo Japan Research Centre for Astronomy and Earth Sciences Budapest Hungary Athens Greece National Space Science Centre NSSC Chinese Academy of Sciences Beijing China DLR Institute of Planetary Research Berlin Germany Hong Kong University Hong Kong Department of Biology and Biotechnology Sapienza University of Rome Rome Italy School of Physical Sciences The Open University Milton Keynes United Kingdom Department of Ecological and Biological Sciences University of Tuscia Viterbo Italy Physical Research Lab

Mars exploration motivates the search for extraterrestrial life, the development of space technologies, and the design of human missions and habitations. Here, we seek new insights and pose unresolved questions relating to the natural history of Mars, habitability, robotic and human exploration, planetary protection, and the impacts on human society. Key observations and findings include: - high escape rates of early Mars' atmosphere, including loss of water, impact present-day habitability;- putative fossils on Mars will likely be ambiguous biomarkers for life;- microbial contamination resulting from human habitation is unavoidable;and - based on Mars' current planetary protection category, robotic payload(s) should characterize the local martian environment for any life-forms prior to human habitation. Some of the outstanding questions are: - which interpretation of the hemispheric dichotomy of the planet is correct;- to what degree did deep-penetrating faults transport subsurface liquids to Mars' surface;- in what abundance are carbonates formed by atmospheric processes;- what properties of martian meteorites could be used to constrain their source locations;- the origin(s) of organic macromolecules;- was/is Mars inhabited;- how can missions designed to uncover microbial activity in the subsurface eliminate potential false positives caused by microbial contaminants from Earth;- how can we ensure that humans and microbes form a stable and benign biosphere;and - should humans relate to putative extraterrestrial life from a biocentric viewpoint (preservation of all biology), or anthropocentric viewpoint of expanding habitation of space? Studies of Mars' evolution can shed light on the habitability of extrasolar planets. In addition, Mars exploration can drive future policy developments and confirm (or put into question) the feasibility and/or extent of human habitability of space. © 2021, CC BY.

关键词： Extrasolar planets

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The SPT-Deep Cluster Catalog: Sunyaev-Zel’dovich Selected Clusters from Combined SPT-3G and SPTpol Measurements over 100 Square Degrees

arXiv

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arXiv 2025年

作者： Kornoelje, K. Bleem, L.E. Rykoff, E.S. Abbott, T.M.C. Ade, P.A.R. Aguena, M. Alves, O. Anderson, A.J. Andrade-Oliveira, F. Ansarinejad, B. Archipley, M. Ashby, M.L.N. Austermann, J.E. Bacon, D. Balkenhol, L. Bayliss, Matthew B. Beall, J.A. Benabed, K. Bender, A.N. Benson, B.A. Bianchini, F. Bocquet, S. Bouchet, F.R. Brooks, D. Burke, D.L. Calzadilla, M. Campitiello, M.G. Camphuis, E. Carlstrom, J.E. Carnero Rosell, A. Carretero, J. Chang, C.L. Chaubal, P. Chiang, H.C. Chichura, P.M. Chokshi, A. Chou, T.-L. Citron, R. Coerver, A. Corbett Moran, C. Costanzi, M. Crawford, T.M. Crites, A.T. da Costa, L.N. Daley, C. de Haan, T. De Vicente, J. Desai, S. Dibert, K.R. Dobbs, M.A. Doel, P. Doohan, M. Doussot, A. Dutcher, D. Everett, W. Everett, S. Feng, C. Ferguson, K.R. Mena-Fern’andez, J. Ferrero, I. Fichman, K. Flaugher, B. Floyd, B. Foster, A. Friedel, D. Frieman, J. Galli, S. Gallicchio, J. Gambrel, A.E. Garc’ia-Bellido, J. Gardner, R.W. Gassis, R. Gatti, M. Ge, F. George, E.M. Giannini, G. Goeckner-Wald, N. Grandis, S. Gruen, D. Gruendl, R.A. Gualtieri, R. Guidi, F. Guns, S. Gupta, N. Gutierrez, G. Halverson, N.W. Hinton, S.R. Hivon, E. Holder, G.P. Hollowood, D.L. Holzapfel, W.L. Honscheid, K. Hood, J.C. Hrubes, J.D. Hryciuk, A. Huang, N. Hubmayr, J. Irwin, K.D. James, D.J. Kéruzoré, F. Khalife, A.R. Klein, M. Knox, L. Korman, M. Kuehn, K. Kuo, C.-L. Lahav, O. Lee, A.T. Lee, S. Levy, K. Li, D. Lima, M. Lowitz, A.E. Lowitz, A. Lu, C. Mahler, Guillaume Maniyar, A. Marshal, J.L. Marshall, J.L. Martsen, E.S. McDonald, M. McMahon, J.J. Menanteau, F. Millea, M. Miquel, R. Mohr, J.J. Montgomery, J. Myles, J. Nakato, Y. Natoli, T. Nibarger, J.P. Noble, G.I. Novosad, V. Ogando, R.L.C. Omori, Y. Ouellette, A. Padin, S. Pan, Z. Patil, S. Pereira, M.E.S. Phadke, K.A. Pieres, A. Plazas Malag’on, A.A. Pollak, A.W. Prabhu, K. Pryke, C. Quan, W. Rahimi, M. Rahlin, A. Reichardt, C.L. Rodr’iguez-Monroy, M. Department of Astronomy and Astrophysics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States Kavli Institute for Cosmological Physics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States High-Energy Physics Division Argonne National Laboratory 9700 South Cass Avenue. LemontIL60439 United States Kavli Institute for Particle Astrophysics and Cosmology Stanford University 452 Lomita Mall StanfordCA94305 United States Cerro Tololo Inter-American Observatory NSF’s National Optical-Infrared Astronomy Research Laboratory Casilla 603 La Serena Chile School of Physics and Astronomy Cardiff University CardiffCF24 3YB United Kingdom Laboratório Interinstitucional de e-Astronomia - LIneA Rua Gal. José Cristino 77 RJ Rio de Janeiro20921-400 Brazil Department of Physics University of Michigan 450 Church Street Ann ArborMI48109 United States Fermi National Accelerator Laboratory MS209 P.O. Box 500 BataviaIL60510 United States School of Physics University of Melbourne ParkvilleVIC3010 Australia Center for Astrophysics Harvard & Smithsonian Optical and Infrared Astronomy Division CambridgeMA01238 United States NIST Quantum Devices Group 325 Broadway Mail-code 817.03 BoulderCO80305 United States Department of Physics University of Colorado BoulderCO80309 United States Institute of Cosmology and Gravitation University of Portsmouth PortsmouthPO1 3FX United Kingdom Sorbonne Université CNRS UMR 7095 Institut d’Astrophysique de Paris 98 bis bd Arago Paris75014 France University Observatory Faculty of Physics Ludwig-Maximilians-Universität Scheinerstr. 1 Munich81679 Germany Department of Physics & Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo ParkCA94025 United States Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology 77 Massachusetts Avenue CambridgeMA02139

We present a catalog of 500 galaxy cluster candidates in the SPT-Deep field: a 100 deg2 field that combines data from the SPT-3G and SPTpol surveys to reach noise levels of 3.0, 2.2, and 9.0 µK-arcmin at 95, 150, and 220 GHz, respectively. This is comparable to noise levels expected for the wide field survey of CMB-S4, a next-generation CMB experiment. Candidates are selected via the thermal Sunyaev-Zel’dovich (SZ) effect with a minimum significance of ξ = 4.0, resulting in a catalog of purity ∼ 89%. Optical data from the Dark Energy Survey and infrared data from the Spitzer space Telescope are used to confirm 442 cluster candidates. The clusters span 0.12 14M☉/h70 500c 14M☉/h70. The sample’s median redshift is 0.74 and the median mass is 1.7 × 1014M☉/h70;these are the lowest median mass and highest median redshift of any SZ-selected sample to date. We assess the effect of infrared emission from cluster member galaxies on cluster selection by performing a joint fit to the infrared dust and tSZ signals by combining measurements from SPT and overlapping submillimeter data from Herschel/SPIRE. We find that at high redshift (z > 1), the tSZ signal is reduced by 17.4+3−2.19% (3.7+0−0.77%) at 150 GHz (95 GHz) due to dust contamination. We repeat our cluster finding method on dust-nulled SPT maps and find the resulting catalog is consistent with the nominal SPT-Deep catalog, demonstrating dust contamination does not significantly impact the SPT-Deep selection function;we attribute this lack of bias to the inclusion of the SPT 220 GHz band. © 2025, CC BY.

关键词： Dark energy

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First M87 Event Horizon Telescope Results IX: Detection of Near-Horizon Circular Polarization

arXiv

引用

arXiv 2023年

作者： Akiyama, Kazunori Alberdi, Antxon Alef, Walter Algaba, Juan Carlos Anantua, Richard Asada, Keiichi Azulay, Rebecca Bach, Uwe Baczko, Anne-Kathrin Ball, David Baloković, Mislav Bandyopadhyay, Bidisha Barrett, John Bauböck, Michi Benson, Bradford A. Bintley, Dan Blackburn, Lindy Blundell, Raymond Bouman, Katherine L. Bower, Geoffrey C. Boyce, Hope Bremer, Michael Brinkerink, Christiaan D. Brissenden, Roger Britzen, Silke Broderick, Avery E. Broguiere, Dominique Bronzwaer, Thomas Bustamante, Sandra Byun, Do-Young Carlstrom, John E. Ceccobello, Chiara Chael, Andrew Chan, Chi-Kwan Chang, Dominic O. Chatterjee, Koushik Chatterjee, Shami Chen, Ming-Tang Chen, Yongjun Cheng, Xiaopeng Cho, Ilje Christian, Pierre Conroy, Nicholas S. Conway, John E. Cordes, James M. Crawford, Thomas M. Crew, Geoffrey B. Cruz-Osorio, Alejandro Cui, Yuzhu Dahale, Rohan Davelaar, Jordy De Laurentis, Mariafelicia Deane, Roger Dempsey, Jessica Desvignes, Gregory Dexter, Jason Dhruv, Vedant Dihingia, Indu K. Doeleman, Sheperd S. Dougal, Sean Dzib, Sergio A. Eatough, Ralph P. Emami, Razieh Falcke, Heino Farah, Joseph Fish, Vincent L. Fomalont, Ed Ford, H. Alyson Foschi, Marianna Fraga-Encinas, Raquel Freeman, William T. Friberg, Per Fromm, Christian M. Fuentes, Antonio Galison, Peter Gammie, Charles F. García, Roberto Gentaz, Olivier Georgiev, Boris Goddi, Ciriaco Gold, Roman Gómez-Ruiz, Arturo I. Gómez, José L. Gu, Minfeng Gurwell, Mark Hada, Kazuhiro Haggard, Daryl Haworth, Kari Hecht, Michael H. Hesper, Ronald Heumann, Dirk Ho, Luis C. Ho, Paul Honma, Mareki Huang, Chih-Wei L. Huang, Lei Hughes, David H. Ikeda, Shiro Impellizzeri, C.M. Violette Inoue, Makoto Issaoun, Sara James, David J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton Jiang, Wu Jiménez-Rosales, Alejandra Johnson, Michael D. Jorstad, Svetlana Joshi, Abhishek V. Jung, Taehyun Karami, Mansour Karuppusamy, Ramesh Kawashima, Tomohisa Keating, Garrett K. Kettenis, Mark Kim, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kino, Motoki Koay, Jun Yi Kocherlakota, Prashant Kofuji, Yut Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road WestfordMA01886 United States National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Black Hole Initiative Harvard University 20 Garden Street CambridgeMA02138 United States Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n GranadaE-18008 Spain Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Department of Physics Faculty of Science Universiti Malaya Kuala Lumpur50603 Malaysia Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Department of Physics & Astronomy The University of Texas at San Antonio One UTSA Circle San AntonioTX78249 United States Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. 4 Roosevelt Rd. Taipei10617 Taiwan Departament d’Astronomia i Astrofísica Universitat de València C. Dr. Moliner 50 Burjassot ValènciaE-46100 Spain Observatori Astronòmic Universitat de València C. Catedrático José Beltrán 2 Paterna ValènciaE-46980 Spain Department of Space Earth and Environment Chalmers University of Technology Onsala Space Observatory OnsalaSE-43992 Sweden Steward Observatory Department of Astronomy University of Arizona 933 N. Cherry Ave. TucsonAZ85721 United States Yale Center for Astronomy & Astrophysics Yale University 52 Hillhouse Avenue New HavenCT06511 United States Astronomy Department Universidad de Concepción Casilla 160-C Concepción Chile Department of Physics University of Illinois 1110 West Green Street UrbanaIL61801 United States Fermi National Accelerator Laboratory MS209 P.O. Box 500 BataviaIL60510 United States Department of Astronomy and Astrophysics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States East Asian Observatory 660 N. A’ohoku Place HiloHI96720 United States 660 N. A’ohoku Place HiloHI

Event Horizon Telescope (EHT) observations have revealed a bright ring of emission around the supermassive black hole at the center of the M87 galaxy. EHT images in linear polarization have further identified a coherent spiral pattern around the black hole, produced from ordered magnetic fields threading the emitting plasma. Here, we present the first analysis of circular polarization using EHT data, acquired in 2017, which can potentially provide additional insights into the magnetic fields and plasma composition near the black hole. Interferometric closure quantities provide convincing evidence for the presence of circularly polarized emission on event-horizon scales. We produce images of the circular polarization using both traditional and newly developed methods. All methods find a moderate level of resolved circular polarization across the image (〈|v|〉 int| ∗ © 2023, CC BY.

关键词： Circular polarization

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Constraints on Cosmic Strings Using Data from the Third Advanced LIGO–Virgo Observing Run

引用

Physical Review Letters 2021年第24期126卷 241102-241102页

作者： R. Abbott T. D. Abbott S. Abraham F. Acernese K. Ackley A. Adams C. Adams R. X. Adhikari V. B. Adya C. Affeldt D. Agarwal M. Agathos K. Agatsuma N. Aggarwal O. D. Aguiar L. Aiello A. Ain P. Ajith T. Akutsu K. M. Aleman G. Allen A. Allocca P. A. Altin A. Amato S. Anand A. Ananyeva S. B. Anderson W. G. Anderson M. Ando S. V. Angelova S. Ansoldi J. M. Antelis S. Antier S. Appert Koya Arai Koji Arai Y. Arai S. Araki A. Araya M. C. Araya J. S. Areeda M. Arène N. Aritomi N. Arnaud S. M. Aronson H. Asada Y. Asali G. Ashton Y. Aso S. M. Aston P. Astone F. Aubin P. Auclair P. Aufmuth K. AultONeal C. Austin S. Babak F. Badaracco M. K. M. Bader S. Bae Y. Bae A. M. Baer S. Bagnasco Y. Bai L. Baiotti J. Baird R. Bajpai M. Ball G. Ballardin S. W. Ballmer M. Bals A. Balsamo G. Baltus S. Banagiri D. Bankar R. S. Bankar J. C. Barayoga C. Barbieri B. C. Barish D. Barker P. Barneo S. Barnum F. Barone B. Barr L. Barsotti M. Barsuglia D. Barta J. Bartlett M. A. Barton I. Bartos R. Bassiri A. Basti M. Bawaj J. C. Bayley A. C. Baylor M. Bazzan B. Bécsy V. M. Bedakihale M. Bejger I. Belahcene V. Benedetto D. Beniwal M. G. Benjamin T. F. Bennett J. D. Bentley M. BenYaala F. Bergamin B. K. Berger S. Bernuzzi D. Bersanetti A. Bertolini J. Betzwieser R. Bhandare A. V. Bhandari D. Bhattacharjee S. Bhaumik J. Bidler I. A. Bilenko G. Billingsley R. Birney O. Birnholtz S. Biscans M. Bischi S. Biscoveanu A. Bisht B. Biswas M. Bitossi M.-A. Bizouard J. K. Blackburn J. Blackman C. D. Blair D. G. Blair R. M. Blair F. Bobba N. Bode M. Boer G. Bogaert M. Boldrini F. Bondu E. Bonilla R. Bonnand P. Booker B. A. Boom R. Bork V. Boschi N. Bose S. Bose V. Bossilkov V. Boudart Y. Bouffanais A. Bozzi C. Bradaschia P. R. Brady A. Bramley A. Branch M. Branchesi M. Breschi T. Briant J. H. Briggs A. Brillet M. Brinkmann P. Brockill A. F. Brooks J. Brooks D. D. Brown S. Brunett G. Bruno R. Bruntz J. Bryant A. Buikema T. Bulik H. J. Bulten A. Buonanno R. Buscicchio D. Buskulic L. Cadonati M. Caesar G. Cagnoli C. Cahillane H. W. Cain, III J. Calderón Bustillo J. D LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Louisiana State University Baton Rouge Louisiana 70803 USA Inter-University Centre for Astronomy and Astrophysics Pune 411007 India Dipartimento di Farmacia Università di Salerno I-84084 Fisciano Salerno Italy INFN Sezione di Napoli Complesso Universitario di Monte S.Angelo I-80126 Napoli Italy OzGrav School of Physics and Astronomy Monash University Clayton 3800 Victoria Australia Christopher Newport University Newport News Virginia 23606 USA LIGO Livingston Observatory Livingston Louisiana 70754 USA OzGrav Australian National University Canberra Australian Capital Territory 0200 Australia Max Planck Institute for Gravitational Physics (Albert Einstein Institute) D-30167 Hannover Germany Leibniz Universität Hannover D-30167 Hannover Germany University of Cambridge Cambridge CB2 1TN United Kingdom Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena D-07743 Jena Germany University of Birmingham Birmingham B15 2TT United Kingdom Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) Northwestern University Evanston Illinois 60208 USA Instituto Nacional de Pesquisas Espaciais 12227-010 São José dos Campos São Paulo Brazil Gravity Exploration Institute Cardiff University Cardiff CF24 3AA United Kingdom Gran Sasso Science Institute (GSSI) I-67100 L’Aquila Italy INFN Laboratori Nazionali del Gran Sasso I-67100 Assergi Italy INFN Sezione di Pisa I-56127 Pisa Italy Università di Pisa I-56127 Pisa Italy International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bengaluru 560089 India Gravitational Wave Science Project National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Advanced Technology Center National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan California State University Fullerton Fullerton California 92831 USA NCSA University of Illi

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO–Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10−15. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

关键词： Cosmic strings & domain walls Gravitational waves

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The international pulsar timing array second data release: Search for an isotropic gravitational wave background

arXiv

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arXiv 2022年

作者： Antoniadis, J. Arzoumanian, Z. Babak, S. Bailes, M. Bak Nielsen, A.-S. Baker, P.T. Bassa, C.G. Bécsy, B. Berthereau, A. Bonetti, M. Brazier, A. Brook, P.R. Burgay, M. Burke-Spolaor, S. Caballero, R.N. Casey-Clyde, J.A. Chalumeau, A. Champion, D.J. Charisi, M. Chatterjee, S. Chen, S. Cognard, I. Cordes, J.M. Cornish, N.J. Crawford, F. Cromartie, H.T. Crowter, K. Dai, S. DeCesar, M.E. Demorest, P.B. Desvignes, G. Dolch, T. Drachler, B. Falxa, M. Ferrara, E.C. Fiore, W. Fonseca, E. Gair, J.R. Garver-Daniels, N. Goncharov, B. Good, D.C. Graikou, E. Guillemot, L. Guo, Y.J. Hazboun, J.S. Hobbs, G. Hu, H. Islo, K. Janssen, G.H. Jennings, R.J. Johnson, A.D. Jones, M.L. Kaiser, A.R. Kaplan, D.L. Karuppusamy, R. Keith, M.J. Kelley, L.Z. Kerr, M. Key, J.S. Kramer, M. Lam, M.T. Lamb, W.G. Lazio, T.J.W. Lee, K.J. Lentati, L. Liu, K. Luo, J. Lynch, R.S. Lyne, A.G. Madison, D.R. Main, R.A. Manchester, R.N. McEwen, A. McKee, J.W. McLaughlin, M.A. Mickaliger, M.B. Mingarelli, C.M.F. Ng, C. Nice, D.J. Os Lowski, S. Parthasarathy, A. Pennucci, T.T. Perera, B.B.P. Perrodin, D. Petiteau, A. Pol, N.S. Porayko, N.K. Possenti, A. Ransom, S.M. Ray, P.S. Reardon, D.J. Russell, C.J. Samajdar, A. Sampson, L.M. Sanidas, S. Sarkissian, J.M. Schmitz, K. Schult, L. Sesana, A. Shaifullah, G. Shannon, R.M. Shapiro-Albert, B.J. Siemens, X. Simon, J. Smith, T.L. Speri, L. Spiewak, R. Stairs, I.H. Stappers, B.W. Stinebring, D.R. Swiggum, J.K. Taylor, S.R. Theureau, G. Tiburzi, C. Vallisneri, M. Van Der Wateren, E. Vecchio, A. Verbiest, J.P.W. Vigeland, S.J. Wahl, H. Wang, J.B. Wang, J. Wang, L. Witt, C.A. Zhang, S. Zhu, X.J. Institute of Astrophysics FORTH N. Plastira 100 Heraklion70013 Greece Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 Bonn53121 Germany Argelander Institut für Astronomie Auf dem Hügel 71 Bonn53117 Germany X-Ray Astrophysics Laboratory NASA Goddard Space Flight Center Code 662 GreenbeltMD20771 United States Université de Paris CNRS Astroparticule et Cosmologie Paris75013 France Moscow Institute of Physics and Technology Moscow region Dolgoprudny Russia Centre for Astrophysics and Supercomputing Swinburne University of Technology HawthornVIC3122 Australia Australia Fakultät für Physik Universität Bielefeld Postfach 100131 Bielefeld33501 Germany Department of Physics and Astronomy Widener University One University Place ChesterPA19013 United States ASTRON Netherlands Institute for Radio Astronomy Oude Hoogeveensedijk 4 Dwingeloo7991 PD Netherlands Department of Physics Montana State University BozemanMT59717 United States Laboratoire de Physique et Chimie de l'Environnement et de l'Espace LPC2E UMR7328 Université d'Orléans CNRS Orléans45071 France Station de Radioastronomie de Nançay Observatoire de Paris PSL University CNRS Université d'Orléans Nançay 18330 France Dipartimento di Fisica G. Occhialini Università Degli Studi di Milano-Bicocca Piazza della Scienza 3 Milano20126 Italy INFN Sezione di Milano-Bicocca Piazza della Scienza 3 Milano20126 Italy Cornell Center for Astrophysics and Planetary Science and Department of Astronomy Cornell University IthacaNY14853 United States Department of Physics and Astronomy West Virginia University P.O. Box 6315 MorgantownWV26506 United States Center for Gravitational Waves and Cosmology West Virginia University Chestnut Ridge Research Building MorgantownWV26505 United States 09047 Italy Canadian Institute for Advanced Research CIFAR Azrieli Global Scholar MaRS Centre West Tower 661 University Ave. Suite 505 TorontoONM5G 1M1 Canada Kavli Institute for Astronomy an

We searched for an isotropic stochastic gravitational wave background in the second data release of the International Pulsar Timing Array, a global collabora-tion synthesizing decadal-length pulsar-timing campaigns in North America, Europe, and Australia. In our reference search for a power law strain spectrum of the form hc= A(f=1 yr-1)α, we found strong evidence for a spectrally-similar low-frequency stochastic process of amplitude A = 3.8-2.5+6:3×10-15and spectral index α =-0.5±0.5, where the uncertainties represent 95% credible regions, using information from the auto-and cross-correlation terms between the pulsars in the array. For a spectral index of α =-2/3, as expected from a population of inspiralling supermassive black hole binaries, the recovered amplitude is A = 2.8-0.8+1.2× 10-15. Nonetheless, no significant evidence of the Hellings-Downs correlations that would indicate a gravitational-wave origin was found. We also analyzed the constituent data from the individual pulsar timing arrays in a consistent way, and clearly demonstrate that the combined international data set is more sensitive. Furthermore, we demonstrate that this combined data set produces comparable constraints to recent single-array data sets which have more data than the constituent parts of the combination. Future international data releases will deliver increased sensitivity to gravitational wave radiation, and significantly increase the detection probability. Copyright © 2022, The Authors. All rights reserved.

关键词： Gravity waves

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