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arXiv · 2010.01055

Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole

Dimitrios Psaltis·Lia Medeiros·Pierre Christian·Feryal Ozel·Kazunori Akiyama·Antxon Alberdi·Walter Alef·Keiichi Asada·Rebecca Azulay·David Ball·Mislav Balokovic·John Barrett·Dan Bintley·Lindy Blackburn·Wilfred Boland·Geoffrey C. Bower·Michael Bremer·Christiaan D. Brinkerink·Roger Brissenden·Silke Britzen·Dominique 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·John E. Conway·James M. Cordes·Geoffrey B. Crew·Yuzhu Cui·Jordy Davelaar·Mariafelicia De Laurentis·Roger Deane·Jessica Dempsey·Gregory Desvignes·Jason Dexter·Ralph P. Eatough·Heino Falcke·Vincent L. Fish·Ed Fomalont·Raquel Fraga-Encinas·Per Friberg·Christian M. Fromm·Charles F. Gammie·Roberto García·Olivier Gentaz·Ciriaco Goddi·Jose L. Gomez·Minfeng Gu·Mark Gurwell·Kazuhiro Hada·Ronald Hesper·Luis C. Ho·Paul Ho·Mareki Honma·Chih-Wei L. Huang·Lei Huang·David H. Hughes·Makoto Inoue·Sara Issaoun·David J. James·Buell T. Jannuzi·Michael Janssen·Wu Jiang·Alejandra Jimenez-Rosales·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·Rocco Lico·Jun Liu·Kuo Liu·Elisabetta Liuzzo·Wen-Ping Lo·Andrei P. Lobanov
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Abstract

The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new and clean gravitational test of the black-hole metric in the strong-field regime. We show analytically that spacetimes that deviate from the Kerr metric but satisfy weak-field tests can lead to large deviations in the predicted black-hole shadows that are inconsistent with even the current EHT measurements. We use numerical calculations of regular, parametric, non-Kerr metrics to identify the common characteristic among these different parametrizations that control the predicted shadow size. We show that the shadow-size measurements place significant constraints on deviation parameters that control the second post-Newtonian and higher orders of each metric and are, therefore, inaccessible to weak-field tests. The new constraints are complementary to those imposed by observations of gravitational waves from stellar-mass sources.

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Dimitrios Psaltis, Lia Medeiros, Pierre Christian, Feryal Ozel, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Keiichi Asada, Rebecca Azulay, David Ball, Mislav Balokovic, John Barrett, Dan Bintley, Lindy Blackburn, Wilfred Boland, Geoffrey C. Bower, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Dominique 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, John E. Conway, James M. Cordes, Geoffrey B. Crew, Yuzhu Cui, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Jason Dexter, Ralph P. Eatough, Heino Falcke, Vincent L. Fish, Ed Fomalont, Raquel Fraga-Encinas, Per Friberg, Christian M. Fromm, Charles F. Gammie, Roberto García, Olivier Gentaz, Ciriaco Goddi, Jose L. Gomez, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Ronald Hesper, Luis C. Ho, Paul Ho, Mareki Honma, Chih-Wei L. Huang, Lei Huang, David H. Hughes, Makoto Inoue, Sara Issaoun, David J. James, Buell T. Jannuzi, Michael Janssen, Wu Jiang, Alejandra Jimenez-Rosales, 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, Rocco Lico, Jun Liu, Kuo Liu, Elisabetta Liuzzo, Wen-Ping Lo, Andrei P. Lobanov. 2020-10-02. Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole. https://doi.org/10.1103/physrevlett.125.141104

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