First M87 Event Horizon Telescope Results. III. Data Processing and Calibration

The Event Horizon Telescope Collaboration, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Keiichi Asada, Rebecca Azulay, Anne Kathrin Baczko, David Ball, Mislav Baloković, John Barrett, Dan Bintley, Lindy Blackburn, Wilfred Boland, Katherine L. Bouman, Geoffrey C. Bower, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Avery E. BroderickDominique Broguiere, Thomas Bronzwaer, Do Young Byun, John E. Carlstrom, Andrew Chael, Chi Kwan Chan, Shami Chatterjee, Koushik Chatterjee, Ming Tang Chen, Yongjun Chen, Ilje Cho, Pierre Christian, John E. Conway, James M. Cordes, Geoffrey B. Crew, Yuzhu Cui, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Jason Dexter, Sheperd S. Doeleman, Ralph P. Eatough, Heino Falcke, Vincent L. Fish, Ed Fomalont, Raquel Fraga-Encinas, Per Friberg, Christian M. Fromm, José L. Gómez, Peter Galison, Charles F. Gammie, Roberto Garcia, Olivier Gentaz, Boris Georgiev, Ciriaco Goddi, Roman Gold, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Michael H. Hecht, Ronald Hesper, Luis C. Ho, Paul Ho, Mareki Honma, Chih Wei L. Huang, Lei Huang, David H. Hughes, Shiro Ikeda, Makoto Inoue, Sara Issaoun, David J. James, Buell Tomasson Jannuzi, Michael Janssen, Britton Jeter, Wu Jiang, Michael D. Johnson, Svetlana Jorstad, Taehyun Jung, Mansour Karami, Ramesh Karuppusamy, Tomohisa Kawashima, Garrett K. Keating, Mark Kettenis, Jae Young Kim, Junhan Kim, Jongsoo Kim, Motoki Kino, Jun Yi Koay, Patrick M. Koch, Shoko Koyama, Michael Kramer, Carsten Kramer, Thomas P. Krichbaum, Cheng Yu Kuo, Tod R. Lauer, Sang Sung Lee, Yan Rong Li, Zhiyuan Li, Michael Lindqvist, Kuo Liu, Elisabetta Liuzzo, Wen Ping Lo, Andrei P. Lobanov, Laurent Loinard, Colin Lonsdale, Ru Sen Lu, Nicholas R. Macdonald, Jirong Mao, Sera Markoff, Daniel P Marrone, Alan P. Marscher, Iván Marti-Vidal, Satoki Matsushita, Lynn D. Matthews, Lia Medeiros, Karl M. Menten, Yosuke Mizuno, Izumi Mizuno, James M. Moran, Kotaro Moriyama, Monika Moscibrodzka, Cornelia Müller, Hiroshi Nagai, Neil M. Nagar, Masanori Nakamura, Ramesh Narayan, Gopal Narayanan, Iniyan Natarajan, Roberto Neri, Chunchong Ni, Aristeidis Noutsos, Hiroki Okino, Héctor Olivares, Gisela N. Ortiz-León, Tomoaki Oyama, Feryal Ozel, Daniel C.M. Palumbo, Nimesh Patel, Ue Li Pen, Dominic W. Pesce, Vincent Piétu, Richard Plambeck, Aleksandar Popstefanija, Oliver Porth, Ben Prather, Jorge A. Preciado-López, Dimitrios Psaltis, Hung Yi Pu, Venkatessh Ramakrishnan, Ramprasad Rao, Mark G. Rawlings, Alexander W. Raymond, Luciano Rezzolla, Bart Ripperda, Freek Roelofs, Alan Rogers, Eduardo Ros, Mel Rose, Arash Roshanineshat, Helge Rottmann, Alan L. Roy, Chet Ruszczyk, Benjamin R. Ryan, Kazi L.J. Rygl, Salvador Sánchez, David Sánchez-Arguelles, Mahito Sasada, Tuomas Savolainen, F. Peter Schloerb, Karl Friedrich Schuster, Lijing Shao, Zhiqiang Shen, Des Small, Bong Won Sohn, Jason Soohoo, Fumie Tazaki, Paul Tiede, Remo P.J. Tilanus, Michael Titus, Kenji Toma, Pablo Torne, Tyler Trent, Sascha Trippe, Shuichiro Tsuda, Ilse Van Bemmel, Huib Jan Van Langevelde, Daniel R. Van Rossum, Jan Wagner, John Wardle, Jonathan Weintroub, Norbert Wex, Robert Wharton, Maciek Wielgus, George N. Wong, Qingwen Wu, André Young, Ken Young, Ziri Younsi, Feng Yuan, Ye Fei Yuan, J. Anton Zensus, Guangyao Zhao, Shan Shan Zhao, Ziyan Zhu, Roger Cappallo, Joseph R. Farah, Thomas W. Folkers, Zheng Meyer-Zhao, Daniel Michalik, Andrew Nadolski, Hiroaki Nishioka, Nicolas Pradel, Rurik A. Primiani, Kamal Souccar, Laura Vertatschitsch, Paul Yamaguchi

Research output: Contribution to journalArticle

20 Citations (Scopus)

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.

Original languageEnglish (US)
Article numberL3
JournalAstrophysical Journal Letters
Volume875
Issue number1
DOIs
StatePublished - Apr 10 2019

Fingerprint

event horizon
telescopes
calibration
radio
data products
radio galaxies
assurance
temporal evolution
angular resolution
systematic errors
quasars
closures
horizon
flux density
recording
wavelength
bandwidth
timescale
sensitivity
wavelengths

Keywords

  • black hole physics
  • galaxies: individual (M87, 3C279)
  • galaxies: jets
  • techniques: high angular resolution
  • techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Event Horizon Telescope Collaboration, T., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., ... Yamaguchi, P. (2019). First M87 Event Horizon Telescope Results. III. Data Processing and Calibration. Astrophysical Journal Letters, 875(1), [L3]. https://doi.org/10.3847/2041-8213/ab0c57

First M87 Event Horizon Telescope Results. III. Data Processing and Calibration. / Event Horizon Telescope Collaboration, The; 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.; Garcia, 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 Tomasson; 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; 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.; Marti-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; Ozel, 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 L.J.; 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.

In: Astrophysical Journal Letters, Vol. 875, No. 1, L3, 10.04.2019.

Research output: Contribution to journalArticle

Event Horizon Telescope Collaboration, T, Akiyama, K, Alberdi, A, Alef, W, Asada, K, Azulay, R, Baczko, AK, Ball, D, Baloković, M, Barrett, J, Bintley, D, Blackburn, L, Boland, W, Bouman, KL, Bower, GC, Bremer, M, Brinkerink, CD, Brissenden, R, Britzen, S, Broderick, AE, Broguiere, D, Bronzwaer, T, Byun, DY, Carlstrom, JE, Chael, A, Chan, CK, Chatterjee, S, Chatterjee, K, Chen, MT, Chen, Y, Cho, I, Christian, P, Conway, JE, Cordes, JM, Crew, GB, Cui, Y, Davelaar, J, De Laurentis, M, Deane, R, Dempsey, J, Desvignes, G, Dexter, J, Doeleman, SS, Eatough, RP, Falcke, H, Fish, VL, Fomalont, E, Fraga-Encinas, R, Friberg, P, Fromm, CM, Gómez, JL, Galison, P, Gammie, CF, Garcia, R, Gentaz, O, Georgiev, B, Goddi, C, Gold, R, Gu, M, Gurwell, M, Hada, K, Hecht, MH, Hesper, R, Ho, LC, Ho, P, Honma, M, Huang, CWL, Huang, L, Hughes, DH, Ikeda, S, Inoue, M, Issaoun, S, James, DJ, Jannuzi, BT, Janssen, M, Jeter, B, Jiang, W, Johnson, MD, Jorstad, S, Jung, T, Karami, M, Karuppusamy, R, Kawashima, T, Keating, GK, Kettenis, M, Kim, JY, Kim, J, Kim, J, Kino, M, Koay, JY, Koch, PM, Koyama, S, Kramer, M, Kramer, C, Krichbaum, TP, Kuo, CY, Lauer, TR, Lee, SS, Li, YR, Li, Z, Lindqvist, M, Liu, K, Liuzzo, E, Lo, WP, Lobanov, AP, Loinard, L, Lonsdale, C, Lu, RS, Macdonald, NR, Mao, J, Markoff, S, Marrone, DP, Marscher, AP, Marti-Vidal, I, Matsushita, S, Matthews, LD, Medeiros, L, Menten, KM, Mizuno, Y, Mizuno, I, Moran, JM, Moriyama, K, Moscibrodzka, M, Müller, C, Nagai, H, Nagar, NM, Nakamura, M, Narayan, R, Narayanan, G, Natarajan, I, Neri, R, Ni, C, Noutsos, A, Okino, H, Olivares, H, Ortiz-León, GN, Oyama, T, Ozel, F, Palumbo, DCM, Patel, N, Pen, UL, Pesce, DW, Piétu, V, Plambeck, R, Popstefanija, A, Porth, O, Prather, B, Preciado-López, JA, Psaltis, D, Pu, HY, Ramakrishnan, V, Rao, R, Rawlings, MG, Raymond, AW, Rezzolla, L, Ripperda, B, Roelofs, F, Rogers, A, Ros, E, Rose, M, Roshanineshat, A, Rottmann, H, Roy, AL, Ruszczyk, C, Ryan, BR, Rygl, KLJ, Sánchez, S, Sánchez-Arguelles, D, Sasada, M, Savolainen, T, Schloerb, FP, Schuster, KF, Shao, L, Shen, Z, Small, D, Sohn, BW, Soohoo, J, Tazaki, F, Tiede, P, Tilanus, RPJ, Titus, M, Toma, K, Torne, P, Trent, T, Trippe, S, Tsuda, S, Van Bemmel, I, Van Langevelde, HJ, Van Rossum, DR, Wagner, J, Wardle, J, Weintroub, J, Wex, N, Wharton, R, Wielgus, M, Wong, GN, Wu, Q, Young, A, Young, K, Younsi, Z, Yuan, F, Yuan, YF, Zensus, JA, Zhao, G, Zhao, SS, Zhu, Z, Cappallo, R, Farah, JR, Folkers, TW, Meyer-Zhao, Z, Michalik, D, Nadolski, A, Nishioka, H, Pradel, N, Primiani, RA, Souccar, K, Vertatschitsch, L & Yamaguchi, P 2019, 'First M87 Event Horizon Telescope Results. III. Data Processing and Calibration', Astrophysical Journal Letters, vol. 875, no. 1, L3. https://doi.org/10.3847/2041-8213/ab0c57
Event Horizon Telescope Collaboration T, Akiyama K, Alberdi A, Alef W, Asada K, Azulay R et al. First M87 Event Horizon Telescope Results. III. Data Processing and Calibration. Astrophysical Journal Letters. 2019 Apr 10;875(1). L3. https://doi.org/10.3847/2041-8213/ab0c57
Event Horizon Telescope Collaboration, The ; 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. ; Garcia, 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 Tomasson ; 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 ; 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. ; Marti-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 ; Ozel, 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 L.J. ; 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. / First M87 Event Horizon Telescope Results. III. Data Processing and Calibration. In: Astrophysical Journal Letters. 2019 ; Vol. 875, No. 1.
@article{e606da2ab197411cbd8fc3da235755a2,
title = "First M87 Event Horizon Telescope Results. III. Data Processing and Calibration",
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.",
keywords = "black hole physics, galaxies: individual (M87, 3C279), galaxies: jets, techniques: high angular resolution, techniques: interferometric",
author = "{Event Horizon Telescope Collaboration}, The and Kazunori Akiyama and Antxon Alberdi and Walter Alef and Keiichi Asada and Rebecca Azulay and Baczko, {Anne Kathrin} and David Ball and Mislav Baloković and John Barrett and Dan Bintley and Lindy Blackburn and Wilfred Boland and Bouman, {Katherine L.} and Bower, {Geoffrey C.} and Michael Bremer and Brinkerink, {Christiaan D.} and Roger Brissenden and Silke Britzen and Broderick, {Avery E.} and Dominique Broguiere and Thomas Bronzwaer and Byun, {Do Young} and Carlstrom, {John E.} and Andrew Chael and Chan, {Chi Kwan} and Shami Chatterjee and Koushik Chatterjee and Chen, {Ming Tang} and Yongjun Chen and Ilje Cho and Pierre Christian and Conway, {John E.} and Cordes, {James M.} and Crew, {Geoffrey B.} and Yuzhu Cui and Jordy Davelaar and {De Laurentis}, Mariafelicia and Roger Deane and Jessica Dempsey and Gregory Desvignes and Jason Dexter and Doeleman, {Sheperd S.} and Eatough, {Ralph P.} and Heino Falcke and Fish, {Vincent L.} and Ed Fomalont and Raquel Fraga-Encinas and Per Friberg and Fromm, {Christian M.} and G{\'o}mez, {Jos{\'e} L.} and Peter Galison and Gammie, {Charles F.} and Roberto Garcia and Olivier Gentaz and Boris Georgiev and Ciriaco Goddi and Roman Gold and Minfeng Gu and Mark Gurwell and Kazuhiro Hada and Hecht, {Michael H.} and Ronald Hesper and Ho, {Luis C.} and Paul Ho and Mareki Honma and Huang, {Chih Wei L.} and Lei Huang and Hughes, {David H.} and Shiro Ikeda and Makoto Inoue and Sara Issaoun and James, {David J.} and Jannuzi, {Buell Tomasson} and Michael Janssen and Britton Jeter and Wu Jiang and Johnson, {Michael D.} and Svetlana Jorstad and Taehyun Jung and Mansour Karami and Ramesh Karuppusamy and Tomohisa Kawashima and Keating, {Garrett K.} and Mark Kettenis and Kim, {Jae Young} and Junhan Kim and Jongsoo Kim and Motoki Kino and Koay, {Jun Yi} and Koch, {Patrick M.} and Shoko Koyama and Michael Kramer and Carsten Kramer and Krichbaum, {Thomas P.} and Kuo, {Cheng Yu} and Lauer, {Tod R.} and Lee, {Sang Sung} and Li, {Yan Rong} and Zhiyuan Li and Michael Lindqvist and Kuo Liu and Elisabetta Liuzzo and Lo, {Wen Ping} and Lobanov, {Andrei P.} and Laurent Loinard and Colin Lonsdale and Lu, {Ru Sen} and Macdonald, {Nicholas R.} and Jirong Mao and Sera Markoff and Marrone, {Daniel P} and Marscher, {Alan P.} and Iv{\'a}n Marti-Vidal and Satoki Matsushita and Matthews, {Lynn D.} and Lia Medeiros and Menten, {Karl M.} and Yosuke Mizuno and Izumi Mizuno and Moran, {James M.} and Kotaro Moriyama and Monika Moscibrodzka and Cornelia M{\"u}ller and Hiroshi Nagai and Nagar, {Neil M.} and Masanori Nakamura and Ramesh Narayan and Gopal Narayanan and Iniyan Natarajan and Roberto Neri and Chunchong Ni and Aristeidis Noutsos and Hiroki Okino and H{\'e}ctor Olivares and Ortiz-Le{\'o}n, {Gisela N.} and Tomoaki Oyama and Feryal Ozel and Palumbo, {Daniel C.M.} and Nimesh Patel and Pen, {Ue Li} and Pesce, {Dominic W.} and Vincent Pi{\'e}tu and Richard Plambeck and Aleksandar Popstefanija and Oliver Porth and Ben Prather and Preciado-L{\'o}pez, {Jorge A.} and Dimitrios Psaltis and Pu, {Hung Yi} and Venkatessh Ramakrishnan and Ramprasad Rao and Rawlings, {Mark G.} and Raymond, {Alexander W.} and Luciano Rezzolla and Bart Ripperda and Freek Roelofs and Alan Rogers and Eduardo Ros and Mel Rose and Arash Roshanineshat and Helge Rottmann and Roy, {Alan L.} and Chet Ruszczyk and Ryan, {Benjamin R.} and Rygl, {Kazi L.J.} and Salvador S{\'a}nchez and David S{\'a}nchez-Arguelles and Mahito Sasada and Tuomas Savolainen and Schloerb, {F. Peter} and Schuster, {Karl Friedrich} and Lijing Shao and Zhiqiang Shen and Des Small and Sohn, {Bong Won} and Jason Soohoo and Fumie Tazaki and Paul Tiede and Tilanus, {Remo P.J.} and Michael Titus and Kenji Toma and Pablo Torne and Tyler Trent and Sascha Trippe and Shuichiro Tsuda and {Van Bemmel}, Ilse and {Van Langevelde}, {Huib Jan} and {Van Rossum}, {Daniel R.} and Jan Wagner and John Wardle and Jonathan Weintroub and Norbert Wex and Robert Wharton and Maciek Wielgus and Wong, {George N.} and Qingwen Wu and Andr{\'e} Young and Ken Young and Ziri Younsi and Feng Yuan and Yuan, {Ye Fei} and Zensus, {J. Anton} and Guangyao Zhao and Zhao, {Shan Shan} and Ziyan Zhu and Roger Cappallo and Farah, {Joseph R.} and Folkers, {Thomas W.} and Zheng Meyer-Zhao and Daniel Michalik and Andrew Nadolski and Hiroaki Nishioka and Nicolas Pradel and Primiani, {Rurik A.} and Kamal Souccar and Laura Vertatschitsch and Paul Yamaguchi",
year = "2019",
month = "4",
day = "10",
doi = "10.3847/2041-8213/ab0c57",
language = "English (US)",
volume = "875",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - First M87 Event Horizon Telescope Results. III. Data Processing and Calibration

AU - Event Horizon Telescope Collaboration, The

AU - Akiyama, Kazunori

AU - Alberdi, Antxon

AU - Alef, Walter

AU - Asada, Keiichi

AU - Azulay, Rebecca

AU - Baczko, Anne Kathrin

AU - Ball, David

AU - Baloković, Mislav

AU - Barrett, John

AU - Bintley, Dan

AU - Blackburn, Lindy

AU - Boland, Wilfred

AU - Bouman, Katherine L.

AU - Bower, Geoffrey C.

AU - Bremer, Michael

AU - Brinkerink, Christiaan D.

AU - Brissenden, Roger

AU - Britzen, Silke

AU - Broderick, Avery E.

AU - Broguiere, Dominique

AU - Bronzwaer, Thomas

AU - Byun, Do Young

AU - Carlstrom, John E.

AU - Chael, Andrew

AU - Chan, Chi Kwan

AU - Chatterjee, Shami

AU - Chatterjee, Koushik

AU - Chen, Ming Tang

AU - Chen, Yongjun

AU - Cho, Ilje

AU - Christian, Pierre

AU - Conway, John E.

AU - Cordes, James M.

AU - Crew, Geoffrey B.

AU - Cui, Yuzhu

AU - Davelaar, Jordy

AU - De Laurentis, Mariafelicia

AU - Deane, Roger

AU - Dempsey, Jessica

AU - Desvignes, Gregory

AU - Dexter, Jason

AU - Doeleman, Sheperd S.

AU - Eatough, Ralph P.

AU - Falcke, Heino

AU - Fish, Vincent L.

AU - Fomalont, Ed

AU - Fraga-Encinas, Raquel

AU - Friberg, Per

AU - Fromm, Christian M.

AU - Gómez, José L.

AU - Galison, Peter

AU - Gammie, Charles F.

AU - Garcia, Roberto

AU - Gentaz, Olivier

AU - Georgiev, Boris

AU - Goddi, Ciriaco

AU - Gold, Roman

AU - Gu, Minfeng

AU - Gurwell, Mark

AU - Hada, Kazuhiro

AU - Hecht, Michael H.

AU - Hesper, Ronald

AU - Ho, Luis C.

AU - Ho, Paul

AU - Honma, Mareki

AU - Huang, Chih Wei L.

AU - Huang, Lei

AU - Hughes, David H.

AU - Ikeda, Shiro

AU - Inoue, Makoto

AU - Issaoun, Sara

AU - James, David J.

AU - Jannuzi, Buell Tomasson

AU - Janssen, Michael

AU - Jeter, Britton

AU - Jiang, Wu

AU - Johnson, Michael D.

AU - Jorstad, Svetlana

AU - Jung, Taehyun

AU - Karami, Mansour

AU - Karuppusamy, Ramesh

AU - Kawashima, Tomohisa

AU - Keating, Garrett K.

AU - Kettenis, Mark

AU - Kim, Jae Young

AU - Kim, Junhan

AU - Kim, Jongsoo

AU - Kino, Motoki

AU - Koay, Jun Yi

AU - Koch, Patrick M.

AU - Koyama, Shoko

AU - Kramer, Michael

AU - Kramer, Carsten

AU - Krichbaum, Thomas P.

AU - Kuo, Cheng Yu

AU - Lauer, Tod R.

AU - Lee, Sang Sung

AU - Li, Yan Rong

AU - Li, Zhiyuan

AU - Lindqvist, Michael

AU - Liu, Kuo

AU - Liuzzo, Elisabetta

AU - Lo, Wen Ping

AU - Lobanov, Andrei P.

AU - Loinard, Laurent

AU - Lonsdale, Colin

AU - Lu, Ru Sen

AU - Macdonald, Nicholas R.

AU - Mao, Jirong

AU - Markoff, Sera

AU - Marrone, Daniel P

AU - Marscher, Alan P.

AU - Marti-Vidal, Iván

AU - Matsushita, Satoki

AU - Matthews, Lynn D.

AU - Medeiros, Lia

AU - Menten, Karl M.

AU - Mizuno, Yosuke

AU - Mizuno, Izumi

AU - Moran, James M.

AU - Moriyama, Kotaro

AU - Moscibrodzka, Monika

AU - Müller, Cornelia

AU - Nagai, Hiroshi

AU - Nagar, Neil M.

AU - Nakamura, Masanori

AU - Narayan, Ramesh

AU - Narayanan, Gopal

AU - Natarajan, Iniyan

AU - Neri, Roberto

AU - Ni, Chunchong

AU - Noutsos, Aristeidis

AU - Okino, Hiroki

AU - Olivares, Héctor

AU - Ortiz-León, Gisela N.

AU - Oyama, Tomoaki

AU - Ozel, Feryal

AU - Palumbo, Daniel C.M.

AU - Patel, Nimesh

AU - Pen, Ue Li

AU - Pesce, Dominic W.

AU - Piétu, Vincent

AU - Plambeck, Richard

AU - Popstefanija, Aleksandar

AU - Porth, Oliver

AU - Prather, Ben

AU - Preciado-López, Jorge A.

AU - Psaltis, Dimitrios

AU - Pu, Hung Yi

AU - Ramakrishnan, Venkatessh

AU - Rao, Ramprasad

AU - Rawlings, Mark G.

AU - Raymond, Alexander W.

AU - Rezzolla, Luciano

AU - Ripperda, Bart

AU - Roelofs, Freek

AU - Rogers, Alan

AU - Ros, Eduardo

AU - Rose, Mel

AU - Roshanineshat, Arash

AU - Rottmann, Helge

AU - Roy, Alan L.

AU - Ruszczyk, Chet

AU - Ryan, Benjamin R.

AU - Rygl, Kazi L.J.

AU - Sánchez, Salvador

AU - Sánchez-Arguelles, David

AU - Sasada, Mahito

AU - Savolainen, Tuomas

AU - Schloerb, F. Peter

AU - Schuster, Karl Friedrich

AU - Shao, Lijing

AU - Shen, Zhiqiang

AU - Small, Des

AU - Sohn, Bong Won

AU - Soohoo, Jason

AU - Tazaki, Fumie

AU - Tiede, Paul

AU - Tilanus, Remo P.J.

AU - Titus, Michael

AU - Toma, Kenji

AU - Torne, Pablo

AU - Trent, Tyler

AU - Trippe, Sascha

AU - Tsuda, Shuichiro

AU - Van Bemmel, Ilse

AU - Van Langevelde, Huib Jan

AU - Van Rossum, Daniel R.

AU - Wagner, Jan

AU - Wardle, John

AU - Weintroub, Jonathan

AU - Wex, Norbert

AU - Wharton, Robert

AU - Wielgus, Maciek

AU - Wong, George N.

AU - Wu, Qingwen

AU - Young, André

AU - Young, Ken

AU - Younsi, Ziri

AU - Yuan, Feng

AU - Yuan, Ye Fei

AU - Zensus, J. Anton

AU - Zhao, Guangyao

AU - Zhao, Shan Shan

AU - Zhu, Ziyan

AU - Cappallo, Roger

AU - Farah, Joseph R.

AU - Folkers, Thomas W.

AU - Meyer-Zhao, Zheng

AU - Michalik, Daniel

AU - Nadolski, Andrew

AU - Nishioka, Hiroaki

AU - Pradel, Nicolas

AU - Primiani, Rurik A.

AU - Souccar, Kamal

AU - Vertatschitsch, Laura

AU - Yamaguchi, Paul

PY - 2019/4/10

Y1 - 2019/4/10

N2 - 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.

AB - 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.

KW - black hole physics

KW - galaxies: individual (M87, 3C279)

KW - galaxies: jets

KW - techniques: high angular resolution

KW - techniques: interferometric

UR - http://www.scopus.com/inward/record.url?scp=85064448206&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064448206&partnerID=8YFLogxK

U2 - 10.3847/2041-8213/ab0c57

DO - 10.3847/2041-8213/ab0c57

M3 - Article

AN - SCOPUS:85064448206

VL - 875

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

SN - 2041-8205

IS - 1

M1 - L3

ER -