Title: | First M87 Event Horizon Telescope Results. III. Data Processing and Calibration |
Authors: | Event Horizon Telescope Collaboration Akiyama, Kazunori Alberdi, Antxon Alef, Walter Asada, Keiichi Azulay, Rebecca Baczko, Anne-Kathrin Ball, David Baloković, Mislav Barrett, John Bintley, Dan Blackburn, Lindy Boland, Wilfred Bouman, Katherine L. Bower, Geoffrey C. Bremer, Michael Brinkerink, Christiaan D. Brissenden, Roger Britzen, Silke Broderick, Avery E. Broguiere, Dominique Bronzwaer, Thomas Byun, Do-Young Carlstrom, John E. Chael, Andrew Chan, Chi-kwan Chatterjee, Shami Chatterjee, Koushik Chen, Ming-Tang Chen, Yongjun Cho, Ilje Christian, Pierre Conway, John E. Cordes, James M. Crew, Geoffrey B. Cui, Yuzhu Davelaar, Jordy De Laurentis, Mariafelicia Deane, Roger Dempsey, Jessica Desvignes, Gregory Dexter, Jason Doeleman, Sheperd S. Eatough, Ralph P. Falcke, Heino Fish, Vincent L. Fomalont, Ed Fraga-Encinas, Raquel Friberg, Per Fromm, Christian M. Gómez, José L. Galison, Peter Gammie, Charles F. García, Roberto Gentaz, Olivier Georgiev, Boris GODDI, CIRIACO Gold, Roman Gu, Minfeng Gurwell, Mark Hada, Kazuhiro Hecht, Michael H. Hesper, Ronald Ho, Luis C. Ho, Paul Honma, Mareki Huang, Chih-Wei L. Huang, Lei Hughes, David H. Ikeda, Shiro Inoue, Makoto Issaoun, Sara James, David J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton Jiang, Wu Johnson, Michael D. Jorstad, Svetlana Jung, Taehyun Karami, Mansour Karuppusamy, Ramesh Kawashima, Tomohisa Keating, Garrett K. Kettenis, Mark Kim, Jae-Young Kim, Junhan Kim, Jongsoo Kino, Motoki Koay, Jun Yi Koch, Patrick M. Koyama, Shoko Kramer, Michael Kramer, Carsten Krichbaum, Thomas P. Kuo, Cheng-Yu Lauer, Tod R. Lee, Sang-Sung Li, Yan-Rong Li, Zhiyuan Lindqvist, Michael Liu, Kuo LIUZZO, Elisabetta Teodorina Lo, Wen-Ping Lobanov, Andrei P. Loinard, Laurent Lonsdale, Colin Lu, Ru-Sen MacDonald, Nicholas R. Mao, Jirong Markoff, Sera Marrone, Daniel P. Marscher, Alan P. Martí-Vidal, Iván Matsushita, Satoki Matthews, Lynn D. Medeiros, Lia Menten, Karl M. Mizuno, Yosuke Mizuno, Izumi Moran, James M. Moriyama, Kotaro Moscibrodzka, Monika Müller, Cornelia Nagai, Hiroshi Nagar, Neil M. Nakamura, Masanori Narayan, Ramesh Narayanan, Gopal Natarajan, Iniyan Neri, Roberto Ni, Chunchong Noutsos, Aristeidis Okino, Hiroki Olivares, Héctor Ortiz-León, Gisela N. Oyama, Tomoaki Özel, Feryal Palumbo, Daniel C. M. Patel, Nimesh Pen, Ue-Li Pesce, Dominic W. Piétu, Vincent Plambeck, Richard PopStefanija, Aleksandar Porth, Oliver Prather, Ben Preciado-López, Jorge A. Psaltis, Dimitrios Pu, Hung-Yi Ramakrishnan, Venkatessh Rao, Ramprasad Rawlings, Mark G. Raymond, Alexander W. Rezzolla, Luciano Ripperda, Bart Roelofs, Freek Rogers, Alan Ros, Eduardo Rose, Mel Roshanineshat, Arash Rottmann, Helge Roy, Alan L. Ruszczyk, Chet Ryan, Benjamin R. RYGL, Kazi Lucie Jessica Sánchez, Salvador Sánchez-Arguelles, David Sasada, Mahito Savolainen, Tuomas Schloerb, F. Peter Schuster, Karl-Friedrich Shao, Lijing Shen, Zhiqiang Small, Des Sohn, Bong Won SooHoo, Jason Tazaki, Fumie Tiede, Paul Tilanus, Remo P. J. Titus, Michael Toma, Kenji Torne, Pablo Trent, Tyler Trippe, Sascha Tsuda, Shuichiro van Bemmel, Ilse van Langevelde, Huib Jan van Rossum, Daniel R. Wagner, Jan Wardle, John Weintroub, Jonathan Wex, Norbert Wharton, Robert Wielgus, Maciek Wong, George N. Wu, Qingwen Young, André Young, Ken Younsi, Ziri Yuan, Feng Yuan, Ye-Fei Zensus, J. Anton Zhao, Guangyao Zhao, Shan-Shan Zhu, Ziyan Cappallo, Roger Farah, Joseph R. Folkers, Thomas W. Meyer-Zhao, Zheng Michalik, Daniel Nadolski, Andrew Nishioka, Hiroaki Pradel, Nicolas Primiani, Rurik A. Souccar, Kamal Vertatschitsch, Laura Yamaguchi, Paul |
Issue Date: | 2019 |
Journal: | THE ASTROPHYSICAL JOURNAL LETTERS |
Number: | 875 |
Issue: | 1 |
First Page: | L3 |
Abstract: | We present the calibration and reduction of Event Horizon Telescope (EHT) 1.3 mm radio wavelength observations of the supermassive black hole candidate at the center of the radio galaxy M87 and the quasar 3C 279, taken during the 2017 April 5-11 observing campaign. These global very long baseline interferometric observations include for the first time the highly sensitive Atacama Large Millimeter/submillimeter Array (ALMA); reaching an angular resolution of 25 μas, with characteristic sensitivity limits of ∼1 mJy on baselines to ALMA and ∼10 mJy on other baselines. The observations present challenges for existing data processing tools, arising from the rapid atmospheric phase fluctuations, wide recording bandwidth, and highly heterogeneous array. In response, we developed three independent pipelines for phase calibration and fringe detection, each tailored to the specific needs of the EHT. The final data products include calibrated total intensity amplitude and phase information. They are validated through a series of quality assurance tests that show consistency across pipelines and set limits on baseline systematic errors of 2% in amplitude and 1° in phase. The M87 data reveal the presence of two nulls in correlated flux density at ∼3.4 and ∼8.3 Gλ and temporal evolution in closure quantities, indicating intrinsic variability of compact structure on a timescale of days, or several light-crossing times for a few billion solar-mass black hole. These measurements provide the first opportunity to image horizon-scale structure in M87. |
URI: | http://hdl.handle.net/20.500.12386/29343 |
URL: | https://iopscience.iop.org/article/10.3847/2041-8213/ab0c57 |
ISSN: | 2041-8205 |
DOI: | 10.3847/2041-8213/ab0c57 |
Bibcode ADS: | 2019ApJ...875L...3E |
Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista
|