A Caltech Library Service

First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration

Akiyama, Kazunori and Alberdi, Antxon and Alef, Walter and Algaba, Juan Carlos and Anantua, Richard and Asada, Keiichi and Azulay, Rebecca and Bach, Uwe and Baczko, Anne-Kathrin and Ball, David and Baloković, Mislav and Barrett, John and Bauböck, Michi and Benson, Bradford A. and Bintley, Dan and Blackburn, Lindy and Blundell, Raymond and Bouman, Katherine L. and Bower, Geoffrey C. and Boyce, Hope and Bremer, Michael and Brinkerink, Christiaan D. and Brissenden, Roger and Britzen, Silke and Broderick, Avery E. and Broguiere, Dominique and Bronzwaer, Thomas and Bustamante, Sandra and Byun, Do-Young and Carlstrom, John E. and Ceccobello, Chiara and Chael, Andrew and Chan, Chi-kwan and Chatterjee, Koushik and Chatterjee, Shami and Chen, Ming-Tang and Chen, Yongjun and Cheng, Xiaopeng and Cho, Ilje and Christian, Pierre and Conroy, Nicholas S. and Conway, John E. and Cordes, James M. and Crawford, Thomas M. and Crew, Geoffrey B. and Cruz-Osorio, Alejandro and Cui, Yuzhu and Davelaar, Jordy and De Laurentis, Mariafelicia and Deane, Roger and Dempsey, Jessica and Desvignes, Gregory and Dexter, Jason and Dhruv, Vedant and Doeleman, Sheperd S. and Dougal, Sean and Dzib, Sergio A. and Eatough, Ralph P. and Emami, Razieh and Falcke, Heino and Farah, Joseph and Fish, Vincent L. and Fomalont, Ed and Ford, H. Alyson and Fraga-Encinas, Raquel and Freeman, William T. and Friberg, Per and Fromm, Christian M. and Fuentes, Antonio and Galison, Peter and Gammie, Charles F. and García, Roberto and Gentaz, Olivier and Georgiev, Boris and Goddi, Ciriaco and Gold, Roman and Gómez-Ruiz, Arturo I. and Gómez, José L. and Gu, Minfeng and Gurwell, Mark and Hada, Kazuhiro and Haggard, Daryl and Haworth, Kari and Hecht, Michael H. and Hesper, Ronald and Heumann, Dirk and Ho, Luis C. and Ho, Paul and Honma, Mareki and Huang, Chih-Wei L. and Huang, Lei and Hughes, David H. and Ikeda, Shiro and Impellizzeri, C. M. Violette and Inoue, Makoto and Issaoun, Sara and James, David J. and Jannuzi, Buell T. and Janssen, Michael and Jeter, Britton and Jiang, Wu and Jiménez-Rosales, Alejandra and Johnson, Michael D. and Jorstad, Svetlana and Joshi, Abhishek V. and Jung, Taehyun and Karami, Mansour and Karuppusamy, Ramesh and Kawashima, Tomohisa and Keating, Garrett K. and Kettenis, Mark and Kim, Dong-Jin and Kim, Jae-Young and Kim, Jongsoo and Kim, Junhan and Kino, Motoki and Koay, Jun Yi and Kocherlakota, Prashant and Kofuji, Yutaro and Koch, Patrick M. and Koyama, Shoko and Kramer, Carsten and Kramer, Michael and Krichbaum, Thomas P. and Kuo, Cheng-Yu and Bella, Noemi La and Lauer, Tod R. and Lee, Daeyoung and Lee, Sang-Sung and Leung, Po Kin and Levis, Aviad and Li, Zhiyuan and Lico, Rocco and Lindahl, Greg and Lindqvist, Michael and Lisakov, Mikhail and Liu, Jun and Liu, Kuo and Liuzzo, Elisabetta and Lo, Wen-Ping and Lobanov, Andrei P. and Loinard, Laurent and Lonsdale, Colin J. and Lu, Ru-Sen and Mao, Jirong and Marchili, Nicola and Markoff, Sera and Marrone, Daniel P. and Marscher, Alan P. and Martí-Vidal, Iván and Matsushita, Satoki and Matthews, Lynn D. and Medeiros, Lia and Menten, Karl M. and Michalik, Daniel and Mizuno, Izumi and Mizuno, Yosuke and Moran, James M. and Moriyama, Kotaro and Moscibrodzka, Monika and Müller, Cornelia and Mus, Alejandro and Musoke, Gibwa and Myserlis, Ioannis and Nadolski, Andrew and Nagai, Hiroshi and Nagar, Neil M. and Nakamura, Masanori and Narayan, Ramesh and Narayanan, Gopal and Natarajan, Iniyan and Nathanail, Antonios and Fuentes, Santiago Navarro and Neilsen, Joey and Neri, Roberto and Ni, Chunchong and Noutsos, Aristeidis and Nowak, Michael A. and Oh, Junghwan and Okino, Hiroki and Olivares, Héctor and Ortiz-León, Gisela N. and Oyama, Tomoaki and Özel, Feryal and Palumbo, Daniel C. M. and Paraschos, Georgios Filippos and Park, Jongho and Parsons, Harriet and Patel, Nimesh and Pen, Ue-Li and Pesce, Dominic W. and Piétu, Vincent and Plambeck, Richard and PopStefanija, Aleksandar and Porth, Oliver and Pötzl, Felix M. and Prather, Ben and Preciado-López, Jorge A. and Psaltis, Dimitrios and Pu, Hung-Yi and Ramakrishnan, Venkatessh and Rao, Ramprasad and Rawlings, Mark G. and Raymond, Alexander W. and Rezzolla, Luciano and Ricarte, Angelo and Ripperda, Bart and Roelofs, Freek and Rogers, Alan and Ros, Eduardo and Romero-Cañizales, Cristina and Roshanineshat, Arash and Rottmann, Helge and Roy, Alan L. and Ruiz, Ignacio and Ruszczyk, Chet and Rygl, Kazi L. J. and Sánchez, Salvador and Sánchez-Argüelles, David and Sánchez-Portal, Miguel and Sasada, Mahito and Satapathy, Kaushik and Savolainen, Tuomas and Schloerb, F. Peter and Schonfeld, Jonathan and Schuster, Karl-Friedrich and Shao, Lijing and Shen, Zhiqiang and Small, Des and Sohn, Bong Won and SooHoo, Jason and Souccar, Kamal and Sun, He and Tazaki, Fumie and Tetarenko, Alexandra J. and Tiede, Paul and Tilanus, Remo P. J. and Titus, Michael and Torne, Pablo and Traianou, Efthalia and Trent, Tyler and Trippe, Sascha and Turk, Matthew and van Bemmel, Ilse and van Langevelde, Huib Jan and van Rossum, Daniel R. and Vos, Jesse and Wagner, Jan and Ward-Thompson, Derek and Wardle, John and Weintroub, Jonathan and Wex, Norbert and Wharton, Robert and Wielgus, Maciek and Wiik, Kaj and Witzel, Gunther and Wondrak, Michael F. and Wong, George N. and Wu, Qingwen and Yamaguchi, Paul and Yoon, Doosoo and Young, André and Young, Ken and Younsi, Ziri and Yuan, Feng and Yuan, Ye-Fei and Zensus, J. Anton and Zhang, Shuo and Zhao, Guang-Yao and Zhao, Shan-Shan and Agurto, Claudio and Araneda, Juan Pablo and Arriagada, Oriel and Bertarini, Alessandra and Berthold, Ryan and Blanchard, Jay and Brown, Ken and Cárdenas, Mauricio and Cantzler, Michael and Caro, Patricio and Chuter, Tim C. and Ciechanowicz, Miroslaw and Coulson, Iain M. and Crowley, Joseph and Degenaar, Nathalie and Dornbusch, Sven and Durán, Carlos A. and Forster, Karl and Geertsema, Gertie and González, Edouard and Graham, Dave and Gueth, Frédéric and Han, Chih-Chiang and Herrera, Cristian and Herrero-Illana, Ruben and Heyminck, Stefan and Hoge, James and Huang, Yau-De and Jiang, Homin and John, David and Klein, Thomas and Kubo, Derek and Kuroda, John and Kwon, Caleb and Laing, Robert and Liu, Ching-Tang and Liu, Kuan-Yu and Mac-Auliffe, Felipe and Martin-Cocher, Pierre and Matulonis, Callie and Messias, Hugo and Meyer-Zhao, Zheng and Montenegro-Montes, Francisco and Montgomerie, William and Muders, Dirk and Nishioka, Hiroaki and Norton, Timothy J. and Olivares, Rodrigo and Pérez-Beaupuits, Juan Pablo and Parra, Rodrigo and Poirier, Michael and Pradel, Nicolas and Raffin, Philippe A. and Ramírez, Jorge and Reynolds, Mark and Saez-Madain, Alejandro F. and Santana, Jorge and Silva, Kevin M. and Sousa, Don and Stahm, William and Torstensson, Karl and Venegas, Paulina and Walther, Craig and Wieching, Gundolf and Wijnands, Rudy and Wouterloot, Jan G. A. (2022) First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration. Astrophysical Journal Letters, 930 (2). Art. No. L13. ISSN 2041-8205. doi:10.3847/2041-8213/ac6675.

[img] PDF - Published Version
Creative Commons Attribution.


Use this Persistent URL to link to this item:


We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of ∼50 μas, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*’s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior.

Item Type:Article
Related URLs:
URLURL TypeDescription
Akiyama, Kazunori0000-0002-9475-4254
Alberdi, Antxon0000-0002-9371-1033
Algaba, Juan Carlos0000-0001-6993-1696
Anantua, Richard0000-0003-3457-7660
Asada, Keiichi0000-0001-6988-8763
Azulay, Rebecca0000-0002-2200-5393
Bach, Uwe0000-0002-7722-8412
Baczko, Anne-Kathrin0000-0003-3090-3975
Baloković, Mislav0000-0003-0476-6647
Barrett, John0000-0002-9290-0764
Bauböck, Michi0000-0002-5518-2812
Benson, Bradford A.0000-0002-5108-6823
Blackburn, Lindy0000-0002-9030-642X
Blundell, Raymond0000-0002-5929-5857
Bouman, Katherine L.0000-0003-0077-4367
Bower, Geoffrey C.0000-0003-4056-9982
Boyce, Hope0000-0002-6530-5783
Brinkerink, Christiaan D.0000-0002-2322-0749
Brissenden, Roger0000-0002-2556-0894
Britzen, Silke0000-0001-9240-6734
Broderick, Avery E.0000-0002-3351-760X
Broguiere, Dominique0000-0001-9151-6683
Bronzwaer, Thomas0000-0003-1151-3971
Bustamante, Sandra0000-0001-6169-1894
Byun, Do-Young0000-0003-1157-4109
Carlstrom, John E.0000-0002-2044-7665
Ceccobello, Chiara0000-0002-4767-9925
Chael, Andrew0000-0003-2966-6220
Chan, Chi-kwan0000-0001-6337-6126
Chatterjee, Koushik0000-0002-2825-3590
Chatterjee, Shami0000-0002-2878-1502
Chen, Ming-Tang0000-0001-6573-3318
Chen, Yongjun0000-0001-5650-6770
Cheng, Xiaopeng0000-0003-4407-9868
Cho, Ilje0000-0001-6083-7521
Christian, Pierre0000-0001-6820-9941
Conroy, Nicholas S.0000-0003-2886-2377
Conway, John E.0000-0003-2448-9181
Cordes, James M.0000-0002-4049-1882
Crawford, Thomas M.0000-0001-9000-5013
Crew, Geoffrey B.0000-0002-2079-3189
Cruz-Osorio, Alejandro0000-0002-3945-6342
Cui, Yuzhu0000-0001-6311-4345
Davelaar, Jordy0000-0002-2685-2434
De Laurentis, Mariafelicia0000-0002-9945-682X
Deane, Roger0000-0003-1027-5043
Dempsey, Jessica0000-0003-1269-9667
Desvignes, Gregory0000-0003-3922-4055
Dexter, Jason0000-0003-3903-0373
Dhruv, Vedant0000-0001-6765-877X
Doeleman, Sheperd S.0000-0002-9031-0904
Dougal, Sean0000-0002-3769-1314
Dzib, Sergio A.0000-0001-6010-6200
Eatough, Ralph P.0000-0001-6196-4135
Emami, Razieh0000-0002-2791-5011
Falcke, Heino0000-0002-2526-6724
Farah, Joseph0000-0003-4914-5625
Fish, Vincent L.0000-0002-7128-9345
Fomalont, Ed0000-0002-9036-2747
Ford, H. Alyson0000-0002-9797-0972
Fraga-Encinas, Raquel0000-0002-5222-1361
Friberg, Per0000-0002-8010-8454
Fromm, Christian M.0000-0002-1827-1656
Fuentes, Antonio0000-0002-8773-4933
Galison, Peter0000-0002-6429-3872
Gammie, Charles F.0000-0001-7451-8935
García, Roberto0000-0002-6584-7443
Gentaz, Olivier0000-0002-0115-4605
Georgiev, Boris0000-0002-3586-6424
Goddi, Ciriaco0000-0002-2542-7743
Gold, Roman0000-0003-2492-1966
Gómez-Ruiz, Arturo I.0000-0001-9395-1670
Gómez, José L.0000-0003-4190-7613
Gu, Minfeng0000-0002-4455-6946
Gurwell, Mark0000-0003-0685-3621
Hada, Kazuhiro0000-0001-6906-772X
Haggard, Daryl0000-0001-6803-2138
Hecht, Michael H.0000-0002-4114-4583
Hesper, Ronald0000-0003-1918-6098
Heumann, Dirk0000-0002-7671-0047
Ho, Luis C.0000-0001-6947-5846
Ho, Paul0000-0002-3412-4306
Honma, Mareki0000-0003-4058-9000
Huang, Chih-Wei L.0000-0001-5641-3953
Huang, Lei0000-0002-1923-227X
Ikeda, Shiro0000-0002-2462-1448
Impellizzeri, C. M. Violette0000-0002-3443-2472
Inoue, Makoto0000-0001-5037-3989
Issaoun, Sara0000-0002-5297-921X
James, David J.0000-0001-5160-4486
Jannuzi, Buell T.0000-0002-1578-6582
Janssen, Michael0000-0001-8685-6544
Jeter, Britton0000-0003-2847-1712
Jiang, Wu0000-0001-7369-3539
Jiménez-Rosales, Alejandra0000-0002-2662-3754
Johnson, Michael D.0000-0002-4120-3029
Jorstad, Svetlana0000-0001-6158-1708
Joshi, Abhishek V.0000-0002-2514-5965
Jung, Taehyun0000-0001-7003-8643
Karami, Mansour0000-0001-7387-9333
Karuppusamy, Ramesh0000-0002-5307-2919
Kawashima, Tomohisa0000-0001-8527-0496
Keating, Garrett K.0000-0002-3490-146X
Kettenis, Mark0000-0002-6156-5617
Kim, Dong-Jin0000-0002-7038-2118
Kim, Jae-Young0000-0001-8229-7183
Kim, Jongsoo0000-0002-1229-0426
Kim, Junhan0000-0002-4274-9373
Kino, Motoki0000-0002-2709-7338
Koay, Jun Yi0000-0002-7029-6658
Kocherlakota, Prashant0000-0001-7386-7439
Koch, Patrick M.0000-0003-2777-5861
Koyama, Shoko0000-0002-3723-3372
Kramer, Carsten0000-0002-4908-4925
Kramer, Michael0000-0002-4175-2271
Krichbaum, Thomas P.0000-0002-4892-9586
Kuo, Cheng-Yu0000-0001-6211-5581
Bella, Noemi La0000-0002-8116-9427
Lauer, Tod R.0000-0003-3234-7247
Lee, Daeyoung0000-0002-3350-5588
Lee, Sang-Sung0000-0002-6269-594X
Leung, Po Kin0000-0002-8802-8256
Levis, Aviad0000-0001-7307-632X
Li, Zhiyuan0000-0003-0355-6437
Lico, Rocco0000-0001-7361-2460
Lindahl, Greg0000-0002-6100-4772
Lindqvist, Michael0000-0002-3669-0715
Lisakov, Mikhail0000-0001-6088-3819
Liu, Jun0000-0002-7615-7499
Liu, Kuo0000-0002-2953-7376
Liuzzo, Elisabetta0000-0003-0995-5201
Lo, Wen-Ping0000-0003-1869-2503
Lobanov, Andrei P.0000-0003-1622-1484
Loinard, Laurent0000-0002-5635-3345
Lonsdale, Colin J.0000-0003-4062-4654
Lu, Ru-Sen0000-0002-7692-7967
Mao, Jirong0000-0002-7077-7195
Marchili, Nicola0000-0002-5523-7588
Markoff, Sera0000-0001-9564-0876
Marrone, Daniel P.0000-0002-2367-1080
Marscher, Alan P.0000-0001-7396-3332
Martí-Vidal, Iván0000-0003-3708-9611
Matsushita, Satoki0000-0002-2127-7880
Matthews, Lynn D.0000-0002-3728-8082
Medeiros, Lia0000-0003-2342-6728
Menten, Karl M.0000-0001-6459-0669
Michalik, Daniel0000-0002-7618-6556
Mizuno, Izumi0000-0002-7210-6264
Mizuno, Yosuke0000-0002-8131-6730
Moran, James M.0000-0002-3882-4414
Moriyama, Kotaro0000-0003-1364-3761
Moscibrodzka, Monika0000-0002-4661-6332
Müller, Cornelia0000-0002-2739-2994
Mus, Alejandro0000-0003-0329-6874
Musoke, Gibwa0000-0003-1984-189X
Myserlis, Ioannis0000-0003-3025-9497
Nadolski, Andrew0000-0001-9479-9957
Nagai, Hiroshi0000-0003-0292-3645
Nagar, Neil M.0000-0001-6920-662X
Nakamura, Masanori0000-0001-6081-2420
Narayan, Ramesh0000-0002-1919-2730
Narayanan, Gopal0000-0002-4723-6569
Natarajan, Iniyan0000-0001-8242-4373
Neilsen, Joey0000-0002-8247-786X
Neri, Roberto0000-0002-7176-4046
Ni, Chunchong0000-0003-1361-5699
Noutsos, Aristeidis0000-0002-4151-3860
Nowak, Michael A.0000-0001-6923-1315
Oh, Junghwan0000-0002-4991-9638
Okino, Hiroki0000-0003-3779-2016
Olivares, Héctor0000-0001-6833-7580
Ortiz-León, Gisela N.0000-0002-2863-676X
Oyama, Tomoaki0000-0003-4046-2923
Özel, Feryal0000-0003-4413-1523
Palumbo, Daniel C. M.0000-0002-7179-3816
Paraschos, Georgios Filippos0000-0001-6757-3098
Park, Jongho0000-0001-6558-9053
Parsons, Harriet0000-0002-6327-3423
Patel, Nimesh0000-0002-6021-9421
Pen, Ue-Li0000-0003-2155-9578
Pesce, Dominic W.0000-0002-5278-9221
Plambeck, Richard0000-0001-6765-9609
Porth, Oliver0000-0002-4584-2557
Pötzl, Felix M.0000-0002-6579-8311
Prather, Ben0000-0002-0393-7734
Preciado-López, Jorge A.0000-0002-4146-0113
Psaltis, Dimitrios0000-0003-1035-3240
Pu, Hung-Yi0000-0001-9270-8812
Ramakrishnan, Venkatessh0000-0002-9248-086X
Rao, Ramprasad0000-0002-1407-7944
Rawlings, Mark G.0000-0002-6529-202X
Raymond, Alexander W.0000-0002-5779-4767
Rezzolla, Luciano0000-0002-1330-7103
Ricarte, Angelo0000-0001-5287-0452
Ripperda, Bart0000-0002-7301-3908
Roelofs, Freek0000-0001-5461-3687
Rogers, Alan0000-0003-1941-7458
Ros, Eduardo0000-0001-9503-4892
Romero-Cañizales, Cristina0000-0001-6301-9073
Roshanineshat, Arash0000-0002-8280-9238
Roy, Alan L.0000-0002-1931-0135
Ruiz, Ignacio0000-0002-0965-5463
Ruszczyk, Chet0000-0001-7278-9707
Rygl, Kazi L. J.0000-0003-4146-9043
Sánchez, Salvador0000-0002-8042-5951
Sánchez-Argüelles, David0000-0002-7344-9920
Sánchez-Portal, Miguel0000-0003-0981-9664
Sasada, Mahito0000-0001-5946-9960
Satapathy, Kaushik0000-0003-0433-3585
Savolainen, Tuomas0000-0001-6214-1085
Schonfeld, Jonathan0000-0002-8909-2401
Schuster, Karl-Friedrich0000-0003-2890-9454
Shao, Lijing0000-0002-1334-8853
Shen, Zhiqiang0000-0003-3540-8746
Small, Des0000-0003-3723-5404
Sohn, Bong Won0000-0002-4148-8378
SooHoo, Jason0000-0003-1938-0720
Souccar, Kamal0000-0001-7915-5272
Sun, He0000-0003-1526-6787
Tazaki, Fumie0000-0003-0236-0600
Tetarenko, Alexandra J.0000-0003-3906-4354
Tiede, Paul0000-0003-3826-5648
Tilanus, Remo P. J.0000-0002-6514-553X
Titus, Michael0000-0001-9001-3275
Torne, Pablo0000-0001-8700-6058
Traianou, Efthalia0000-0002-1209-6500
Trippe, Sascha0000-0003-0465-1559
Turk, Matthew0000-0002-5294-0198
van Bemmel, Ilse0000-0001-5473-2950
van Langevelde, Huib Jan0000-0002-0230-5946
van Rossum, Daniel R.0000-0001-7772-6131
Vos, Jesse0000-0003-3349-7394
Wagner, Jan0000-0003-1105-6109
Ward-Thompson, Derek0000-0003-1140-2761
Wardle, John0000-0002-8960-2942
Weintroub, Jonathan0000-0002-4603-5204
Wex, Norbert0000-0003-4058-2837
Wharton, Robert0000-0002-7416-5209
Wielgus, Maciek0000-0002-8635-4242
Wiik, Kaj0000-0002-0862-3398
Witzel, Gunther0000-0003-2618-797X
Wondrak, Michael F.0000-0002-6894-1072
Wong, George N.0000-0001-6952-2147
Wu, Qingwen0000-0003-4773-4987
Yamaguchi, Paul0000-0002-6017-8199
Yoon, Doosoo0000-0001-8694-8166
Young, André0000-0003-0000-2682
Young, Ken0000-0002-3666-4920
Younsi, Ziri0000-0001-9283-1191
Yuan, Feng0000-0003-3564-6437
Yuan, Ye-Fei0000-0002-7330-4756
Zensus, J. Anton0000-0001-7470-3321
Zhang, Shuo0000-0002-2967-790X
Zhao, Guang-Yao0000-0002-4417-1659
Zhao, Shan-Shan0000-0002-9774-3606
Blanchard, Jay0000-0002-2756-395X
Coulson, Iain M.0000-0002-7316-4626
Degenaar, Nathalie0000-0002-0092-3548
Dornbusch, Sven0000-0003-3211-3352
Durán, Carlos A.0000-0001-7622-3890
Forster, Karl0000-0001-5800-5531
Herrero-Illana, Ruben0000-0002-7758-8717
Kwon, Caleb0000-0001-9006-7345
Laing, Robert0000-0001-6786-3087
Messias, Hugo0000-0002-2985-7994
Montenegro-Montes, Francisco0000-0002-7430-3771
Muders, Dirk0000-0002-2315-2571
Pérez-Beaupuits, Juan Pablo0000-0003-3536-2274
Poirier, Michael0000-0001-6641-0959
Reynolds, Mark0000-0003-1621-9392
Saez-Madain, Alejandro F.0000-0002-0804-3414
Sousa, Don0000-0002-2625-2607
Wijnands, Rudy0000-0002-3516-2152
Wouterloot, Jan G. A.0000-0002-4694-6905
Additional Information:© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2022 February 28; revised 2022 April 4; accepted 2022 April 10; published 2022 May 12. We thank an anonymous referee for their insight and helpful suggestions that have improved this paper. The Event Horizon Telescope Collaboration thanks the following organizations and programs: the Academia Sinica; the Academy of Finland (projects 274477, 284495, 312496, 315721); the Agencia Nacional de Investigación y Desarrollo (ANID), Chile via NCN19_058 (TITANs) and Fondecyt 1221421, the Alexander von Humboldt Stiftung; an Alfred P. Sloan Research Fellowship; Allegro, the European ALMA Regional Centre node in the Netherlands, the NL astronomy research network NOVA and the astronomy institutes of the University of Amsterdam, Leiden University and Radboud University; the ALMA North America Development Fund; the Black Hole Initiative, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation (although the opinions expressed in this work are those of the author(s) and do not necessarily reflect the views of these Foundations); Chandra DD7-18089X and TM6-17006X; the China Scholarship Council; China Postdoctoral Science Foundation fellowship (2020M671266); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects U0004-246083, U0004-259839, F0003-272050, M0037-279006, F0003-281692, 104497, 275201, 263356); the Consejería de Economía, Conocimiento, Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo Superior de Investigaciones Científicas (grant 2019AEP112); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional Autónoma de México (DGAPA-UNAM, projects IN112417 and IN112820); the Dutch Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and grant OCENW.KLEIN.113; the Dutch National Supercomputers, Cartesius and Snellius (NWO Grant 2021.013); the EACOA Fellowship awarded by the East Asia Core Observatories Association, which consists of the Academia Sinica Institute of Astronomy and Astrophysics, the National Astronomical Observatory of Japan, Center for Astronomical Mega-Science, Chinese Academy of Sciences, and the Korea Astronomy and Space Science Institute; the European Research Council (ERC) Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the European Union Horizon 2020 research and innovation programme under grant agreements RadioNet (No 730562) and M2FINDERS (No 101018682); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); MICINN Research Project PID2019-108995GB-C22; the European Research Council for advanced grant "JETSET: Launching, propagation and emission of relativistic jets from binary mergers and across mass scales" (Grant No. 884631); the Institute for Advanced Study; the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; DFG research grant "Jet physics on horizon scales and beyond" (Grant No. FR 4069/2-1); Joint Princeton/Flatiron and Joint Columbia/Flatiron Postdoctoral Fellowships, research at the Flatiron Institute is supported by the Simons Foundation; the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT; grant JPMXP1020200109); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Joint Institute for Computational Fundamental Science, Japan; the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJSSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP21H01137, JP18H03721, JP18K13594, 18K03709, JP19K14761, 18H01245, 25120007); the Malaysian Fundamental Research Grant Scheme (FRGS) FRGS/1/2019/STG02/UM/02/6; the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (103-2119-M-001-010-MY2, 105-2112-M-001-025-MY3, 105-2119-M-001-042, 106-2112-M-001-011, 106-2119-M-001-013, 106-2119-M-001-027, 106-2923-M-001-005, 107-2119-M-001-017, 107-2119-M-001-020, 107-2119-M-001-041, 107-2119-M-110-005, 107-2923-M-001-009, 108-2112-M-001-048, 108-2112-M-001-051, 108-2923-M-001-002, 109-2112-M-001-025, 109-2124-M-001-005, 109-2923-M-001-001, 110-2112-M-003-007-MY2, 110-2112-M-001-033, 110-2124-M-001-007, and 110-2923-M-001-001); the Ministry of Education (MoE) of Taiwan Yushan Young Scholar Program; the Physics Division, National Center for Theoretical Sciences of Taiwan; the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC20K1567, NASA Astrophysics Theory Program grant 80NSSC20K0527, NASA NuSTAR award 80NSSC20K0645); NASA Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555; the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2017YFA0402703, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1440254, AST-1555365, AST-1614868, AST-1615796, AST-1715061, AST-1716327, AST-1716536, OISE-1743747, AST-1816420, AST-1935980, AST-2034306); NSF Astronomy and Astrophysics Postdoctoral Fellowship (AST-1903847); the Natural Science Foundation of China (grants 11650110427, 10625314, 11721303, 11725312, 11873028, 11933007, 11991052, 11991053, 12192220, 12192223); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, the Korea Research Fellowship Program: NRF-2015H1D3A1066561, Brain Pool Program: 2019H1D3A1A01102564, Basic Research Support Grant 2019R1F1A1059721, 2021R1A6A3A01086420, 2022R1C1C1005255); Netherlands Research School for Astronomy (NOVA) Virtual Institute of Accretion (VIA) postdoctoral fellowships; Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Spanish Ministerio de Ciencia e Innovación (grants PGC2018-098915-B-C21, AYA2016-80889-P, PID2019-108995GB-C21, PID2020-117404GB-C21); the University of Pretoria for financial aid in the provision of the new Cluster Server nodes and SuperMicro (USA) for a SEEDING GRANT approved towards these nodes in 2020; the Shanghai Pilot Program for Basic Research, Chinese Academy of Science, Shanghai Branch (JCYJ-SHFY-2021-013); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofísica de Andalucía (SEV-2017- 0709); the Spinoza Prize SPI 78-409; the South African Research Chairs Initiative, through the South African Radio Astronomy Observatory (SARAO, grant ID 77948), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Innovation (DSI) of South Africa; the Toray Science Foundation; Swedish Research Council (VR); the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001); and the YCAA Prize Postdoctoral Fellowship. We thank the staff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01154.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and National Institutes of Natural Sciences of Japan, together with National Research Council (Canada), Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. We also thank the Center for Computational Astrophysics, National Astronomical Observatory of Japan. The computing cluster of Shanghai VLBI correlator supported by the Special Fund for Astronomy from the Ministry of Finance in China is acknowledged. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key Research and Development Program (No. 2017YFA0402700) of China and Natural Science Foundation of China grant 11873028. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrófisica, Óptica, y Electrónica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30-m telescope on Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany) and IGN (Instituto Geográfico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. Support for SPT participation in the EHT is provided by the National Science Foundation through award OPP-1852617 to the University of Chicago. Partial support is also provided by the Kavli Institute of Cosmological Physics at the University of Chicago. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. XSEDE Stampede2 resource at TACC was allocated through TG-AST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. This research is part of the Frontera computing project at the Texas Advanced Computing Center through the Frontera Large-Scale Community Partnerships allocation AST20023. Frontera is made possible by National Science Foundation award OAC-1818253. This research was carried out using resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy Office of Science. Additional work used ABACUS2.0, which is part of the eScience center at Southern Denmark University. Simulations were also performed on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, on the HazelHen cluster at the HLRS in Stuttgart, and on the Pi2.0 and Siyuan Mark-I at Shanghai Jiao Tong University. The computer resources of the Finnish IT Center for Science (CSC) and the Finnish Computing Competence Infrastructure (FCCI) project are acknowledged. This research was enabled in part by support provided by Compute Ontario (, Calcul Quebec ( and Compute Canada ( The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is grateful to T4Science and Microsemi for their assistance with Hydrogen Masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended staff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX. We thank Martin Shepherd for the addition of extra features in the Difmap software that were used for the CLEAN imaging results presented in this paper. We acknowledge the significance that Maunakea, where the SMA and JCMT EHT stations are located, has for the indigenous Hawaiian people. The scientific results reported here are also based in part on observations made by the East Asian VLBI Network (EAVN), the Global 3 mm VLBI Array (GMVA), the Very Large Telescope (VLT), the Neil Gehrels Swift Observatory, the Chandra X-ray Observatory, and the Nuclear Spectroscopic Telescope (NuSTAR). We thank the scheduling, data processing, and archive teams from these facilities for making these observations possible. IMV acknowledges the use of LLuis Vives HPC resources of the University of Valencia. Facility: EHT, ALMA, APEX, IRAM:30 m, JCMT, LMT, SMA, ARO:SMT, SPT, Chandra, EAVN, GMVA, NuSTAR, Swift, VLT. Software: DiFX (Deller et al. 2011), CALC, PolConvert (Martí-Vidal et al. 2016), HOPS (Whitney et al. 2004), EHT-HOPS Pipeline (Blackburn et al. 2019), CASA (McMullin et al. 2007), rPICARD (Janssen et al. 2018, 2019b).
Group:Astronomy Department, Space Radiation Laboratory, NuSTAR
Funding AgencyGrant Number
Academia SinicaUNSPECIFIED
Academy of Finland274477
Academy of Finland284495
Academy of Finland312496
Academy of Finland315721
Agencia Nacional de Investigación y Desarrollo (ANID)NCN19_058
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1221421
Alexander von Humboldt FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Nederlandse Onderzoekschool voor de Astronomie (NOVA)UNSPECIFIED
ALMA North America Development FundUNSPECIFIED
Black Hole InitiativeUNSPECIFIED
John Templeton FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
China Scholarship CouncilUNSPECIFIED
China Postdoctoral Science Foundation2020M671266
Consejo Nacional de Ciencia y Tecnología (CONACYT)U0004-246083
Consejo Nacional de Ciencia y Tecnología (CONACYT)U0004-259839
Consejo Nacional de Ciencia y Tecnología (CONACYT)F0003-272050
Consejo Nacional de Ciencia y Tecnología (CONACYT)M0037-279006
Consejo Nacional de Ciencia y Tecnología (CONACYT)F0003-281692
Consejo Nacional de Ciencia y Tecnología (CONACYT)104497
Consejo Nacional de Ciencia y Tecnología (CONACYT)275201
Consejo Nacional de Ciencia y Tecnología (CONACYT)263356
Junta de AndalucíaP18-FR-1769
Consejo Superior de Investigaciones Científicas2019AEP112
Perimeter Institute for Theoretical PhysicsUNSPECIFIED
Dirección General de Asuntos del Personal Académico-Universidad Nacional Autónoma de México (DGAPA-UNAM)IN112417
Dirección General de Asuntos del Personal Académico-Universidad Nacional Autónoma de México (DGAPA-UNAM)IN112820
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)639.043.513
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)OCENW.KLEIN.113
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)2021.013
East Asia Core Observatories AssociationUNSPECIFIED
European Research Council (ERC)610058
European Research Council (ERC)730562
European Research Council (ERC)101018682
Generalitat ValencianaAPOSTD/2018/177
Generalitat ValencianaCIDEGENT/2018/021
Ministerio de Ciencia e Innovación (MICINN)PID2019-108995GB-C22
European Research Council (ERC)884631
Institute for Advanced StudyUNSPECIFIED
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
International Max Planck Research School for Astronomy and AstrophysicsUNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)FR 4069/2-1
Simons FoundationUNSPECIFIED
Flatiron InstituteUNSPECIFIED
Ministry of Education, Culture, Sports, Science and Technology (MEXT)JPMXP1020200109
Japan Society for the Promotion of Science (JSPS)JP17J08829
Joint Institute for Computational Fundamental ScienceUNSPECIFIED
Chinese Academy of SciencesQYZDJ-SSW-SLH057
Chinese Academy of SciencesQYZDJSSW-SYS008
Chinese Academy of SciencesZDBS-LY-SLH011
Leverhulme TrustUNSPECIFIED
Japan Society for the Promotion of Science (JSPS)18KK0090
Japan Society for the Promotion of Science (JSPS)JP21H01137
Japan Society for the Promotion of Science (JSPS)JP18H03721
Japan Society for the Promotion of Science (JSPS)JP18K13594
Japan Society for the Promotion of Science (JSPS)18K03709
Japan Society for the Promotion of Science (JSPS)JP19K14761
Japan Society for the Promotion of Science (JSPS)18H01245
Japan Society for the Promotion of Science (JSPS)25120007
Malaysian Fundamental Research GrantFRGS/1/2019/STG02/UM/02/6
Massachusetts Institute of Technology (MIT)UNSPECIFIED
Ministry of Science and Technology (Taipei)103-2119-M-001-010-MY2
Ministry of Science and Technology (Taipei)105-2112-M-001-025-MY3
Ministry of Science and Technology (Taipei)105-2119-M-001-042
Ministry of Science and Technology (Taipei)106-2112-M-001-011
Ministry of Science and Technology (Taipei)106-2119-M-001-013
Ministry of Science and Technology (Taipei)106-2119-M-001-027
Ministry of Science and Technology (Taipei)106-2923-M-001-005
Ministry of Science and Technology (Taipei)107-2119-M-001-017
Ministry of Science and Technology (Taipei)107-2119-M-001-020
Ministry of Science and Technology (Taipei)107-2119-M-001-041
Ministry of Science and Technology (Taipei)107-2119-M-110-005
Ministry of Science and Technology (Taipei)107-2923-M-001-009
Ministry of Science and Technology (Taipei)108-2112-M-001-048
Ministry of Science and Technology (Taipei)108-2112-M-001-051
Ministry of Science and Technology (Taipei)108-2923-M-001-002
Ministry of Science and Technology (Taipei)109-2112-M-001-025
Ministry of Science and Technology (Taipei)109-2124-M-001-005
Ministry of Science and Technology (Taipei)109-2923-M-001-001
Ministry of Science and Technology (Taipei)110-2112-M-003-007-MY2
Ministry of Science and Technology (Taipei)110-2112-M-001-033
Ministry of Science and Technology (Taipei)110-2124-M-001-007
Ministry of Science and Technology (Taipei)110-2923-M-001-001
Ministry of Education (Taipei)UNSPECIFIED
National Center for Theoretical Sciences (Taipei)UNSPECIFIED
NASA Hubble FellowshipHST-HF2-51431.001-A
National Institute of Natural Sciences (NINS)UNSPECIFIED
National Key Research and Development Program of China2016YFA0400704
National Key Research and Development Program of China2017YFA0402703
National Key Research and Development Program of China2016YFA0400702
NSF Graduate Research FellowshipDGE-1144085
NSF Astronomy and Astrophysics Postdoctoral FellowshipAST-1903847
National Natural Science Foundation of China11650110427
National Natural Science Foundation of China10625314
National Natural Science Foundation of China11721303
National Natural Science Foundation of China11725312
National Natural Science Foundation of China11873028
National Natural Science Foundation of China11933007
National Natural Science Foundation of China11991052
National Natural Science Foundation of China11991053
National Natural Science Foundation of China12192220
National Natural Science Foundation of China12192223
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
National Youth Thousand Talents Program of ChinaUNSPECIFIED
National Research Foundation of KoreaNRF-2015H1A2A1033752
National Research Foundation of KoreaNRF-2015H1D3A1066561
National Research Foundation of Korea2019H1D3A1A01102564
National Research Foundation of Korea2019R1F1A1059721
National Research Foundation of Korea2021R1A6A3A01086420
National Research Foundation of Korea2022R1C1C1005255
Onsala Space Observatory (OSO)UNSPECIFIED
Swedish Research Council2017-00648
Department of Innovation, Science and Economic Development (Canada)UNSPECIFIED
Ontario Ministry of Research, Innovation and ScienceUNSPECIFIED
Ministerio de Ciencia e Innovación (MICINN)PGC2018-098915-B-C21
Ministerio de Ciencia e Innovación (MICINN)AYA2016-80889-P
Ministerio de Ciencia e Innovación (MICINN)PID2019-108995GB-C21
Ministerio de Ciencia e Innovación (MICINN)PID2020-117404GB-C21
University of PretoriaUNSPECIFIED
SuperMicro CorporationUNSPECIFIED
Chinese Academy of SciencesJCYJ-SHFY-2021-013
Severo OchoaSEV-2017-0709
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)SPI 78-409
South African Radio Astronomy Observatory (SARAO)77948
National Research Foundation (South Africa)UNSPECIFIED
Department of Science and Innovation (South Africa)UNSPECIFIED
Toray Science FoundationUNSPECIFIED
Department of Energy (DOE)89233218CNA000001
Yale Center for Astronomy and AstrophysicsUNSPECIFIED
Department of Energy (DOE)DE-AC05-00OR22725
Ministry of Finance (China)UNSPECIFIED
National Key Research and Development Program of China2017YFA0402700
National Natural Science Foundation of China11873028
Science and Technology Facilities Council (STFC)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Instituto Geográfico Nacional (IGN)UNSPECIFIED
State of ArizonaUNSPECIFIED
Kavli Institute for Cosmological PhysicsUNSPECIFIED
Compute OntarioUNSPECIFIED
Subject Keywords:Black holes
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Black holes (162)
Record Number:CaltechAUTHORS:20220721-8952000
Persistent URL:
Official Citation:Event Horizon Telescope Collaboration et al 2022 ApJL 930 L13
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115750
Deposited By: George Porter
Deposited On:26 Jul 2022 14:32
Last Modified:26 Jul 2022 14:32

Repository Staff Only: item control page