Resolving the Inner Parsec of the Blazar J1924–2914 with the Event Horizon Telescope
Sara Issaoun,Maciek Wielgus,Svetlana Jorstad,Thomas P. Krichbaum,Lindy Blackburn,Michael Janssen,Chi-kwan Chan,Dominic W. Pesce,Jose L. Gomez,Kazunori Akiyama,Monika Moscibrodzka,Ivan Marti-Vidal,Andrew Chael,Rocco Lico,Jun Liu,Venkatessh Ramakrishnan,Mikhail Lisakov,Antonio Fuentes,Guang-Yao Zhao,Kotaro Moriyama,Avery E. Broderick,Paul Tiede,Nicholas R. MacDonald,Yosuke Mizuno,Efthalia Traianou,Laurent Loinard,Jordy Davelaar,Mark Gurwell,Ru-Sen Lu,Antxon Alberdi,Walter Alef,Juan Carlos Algaba,Richard Anantua,Keiichi Asada,Rebecca Azulay,Uwe Bach,Anne-Kathrin Baczko,David Ball,Mislac Balokovic,John Barrett,Michi Baubock,Bradford A. Benson,Dan Bintley,Raymond Blundell,Wilfred Boland,Katherine L. Bouman,Geoffrey C. Bower,Hope Boyce,Michael Bremer,Christiaan D. Brinkerink,Roger Brissenden,Silke Britzen,Dominique Broguiere,Thomas Bronzwaer,Sandra Bustamante,Do-Young Byun,John E. Carlstrom,Chiara Ceccobello,Koushik Chatterjee,Shami Chatterjee,Ming-Tang Chen,Yongjun Chen,Ilje Cho,Pierre Christian,Nicholas S. Conroy,John E. Conway,James M. Cordes,Thomas M. Crawford,Geoffrey B. Crew,Alejandro Cruz-Osorio,Yuzhu Cui,Mariafelicia De Laurentis,Roger Deane,Jessica Dempsey,Gregory Desvignes,Jason Dexter,Sheperd S. Doeleman,Vedant Dhruv,Sergio Abraham Dzib Quijano,Ralph P. Eatough,Razieh Emami,Heino Falcke,Joseph Farah,Vincent L. Fish,Ed Fomalont,H. Alyson Ford,Raquel Fraga-Encinas,William T. Freeman,Per Friberg,Christian M. Fromm,Peter Galison,Charles F. Gammie,Roberto Garcia,Olivier Gentaz,Boris Georgiev,Ciriaco Goddi,Roman Gold,Arturo Gomez-Ruiz,Minfeng Gu,Kazuhiro Hada,Daryl Haggard,Michael H. Hecht,Ronald Hesper,Luis C. Ho,Paul Ho,Mareki Honma,Chih-Wei L. Huang,Lei Huang,David H. Hughes,Shiro Ikeda,C. M. Violette Impellizzeri,Makoto Inoue,David J. James,Buell T. Jannuzi,Britton Jeter,Wu Jiang,Alejandra Jimenez-Rosales,Michael D. Johnson,Abhishek Joshi,Taehyun Jung,Mansour Karami,Ramesh Karuppusamy,Tomohisa Kawashima,Garrett K. Keating,Mark Kettenis,Dong-Jin Kim,Jae-Young Kim,Jongsoo Kim,Junhan Kim,Motoki Kino,Jun Yi Koay,Prashant Kocherlakota,Yutaro Kofuji,Patrick M. Koch,Shoko Koyama,Carsten Kramer,Michael Kramer,Cheng-Yu Kuo,Noemi La Bella,Tod R. Lauer,Daeyoung Lee,Sang-Sung Lee,Po Kin Leung,Aviad Levis,Zhiyuan Li,Greg Lindahl,Michael Lindqvist,Kuo Liu,Elisabetta Liuzzo,Wen-Ping Lo,Andrei P. Lobanov,Colin Lonsdale,Jirong Mao,Nicola Marchili,Sera Markoff,Daniel P. Marrone,Alan P. Marscher,Satoki Matsushita,Lynn D. Matthews,Lia Medeiros,Karl M. Menten,Daniel Michalik,Izumi Mizuno,James M. Moran,Cornelia Mueller,Alejandro Mus,Gibwa Musoke,Ioannis Myserlis,Andrew Nadolski,Hiroshi Nagai,Neil M. Nagar,Masanori Nakamura,Ramesh Narayan,Gopal Narayanan,Iniyan Natarajan,Antonios Nathanail,Joey Neilsen,Roberto Neri,Chunchong Ni,Aristeidis Noutsos,Michael A. Nowak,Junghwan Oh,Hiroki Okino,Hector Olivares,Gisela N. Ortiz-Leon,Tomoaki Oyama,Feryal Ozel,Daniel C. M. Palumbo,Georgios Filippos Paraschos,Jongho Park,Harriet Parsons,Nimesh Patel,Ue-Li Pen,Vincent Pietu,Richard Plambeck,Aleksandar PopStefanija,Oliver Porth,Felix M. Potzl,Ben Prather,Jorge A. Preciado-Lopez,Dimitrios Psaltis,Hung-Yi Pu,Ramprasad Rao,Mark G. Rawlings,Alexander W. Raymond,Luciano Rezzolla,Angelo Ricarte,Bart Ripperda,Freek Roelofs,Alan Rogers,Eduardo Ros,Cristina Romero-Canizales,Arash Roshanineshat,Helge Rottmann,Alan L. Roy,Ignacio Ruiz,Chet Ruszczyk,Kazi L. J. Rygl,Salvador Sanchez,David Sanchez-Arguelles,Miguel Sanchez-Portal,Mahito Sasada,Kaushik Satapathy,Tuomas Savolainen,F. Peter Schloerb,Karl-Friedrich Schuster,Lijing Shao,Zhiqiang Shen,Des Small,Bong Won Sohn,Jason SooHoo,Kamal Souccar,He Sun,Fumie Tazaki,Alexandra J. Tetarenko,Remo P. J. Tilanus,Michael Titus,Pablo Torne,Tyler Trent,Sascha Trippe,Ilse van Bemmel,Huib Jan van Langevelde,Daniel R. van Rossum,Jesse Vos,Jan Wagner,Derek Ward-Thompson,John Wardle,Jonathan Weintroub,Norbert Wex,Robert Wharton,Kaj Wiik,Gunther Witzel,Michael Wondrak,George N. Wong,Qingwen Wu,Paul Yamaguchi,Doosoo Yoon,Andre Young,Ken Young,Ziri Younsi,Feng Yuan,Ye-Fei Yuan,J. Anton Zensus,Shuo Zhang,Shan-Shan Zhao
The blazar J1924–2914 is a primary Event Horizon Telescope (EHT) calibrator for the Galactic center’s black hole Sagittarius A*. Here we present the first total and linearly polarized intensity images of this source obtained with the unprecedented 20 μas resolution of the EHT. J1924–2914 is a very compact flat-spectrum radio source with strong optical variability and polarization. In April 2017 the source was observed quasi-simultaneously with the EHT (April 5–11), the Global Millimeter VLBI Array (April 3), and the Very Long Baseline Array (April 28), giving a novel view of the source at four observing frequencies, 230, 86, 8.7, and 2.3 GHz. These observations probe jet properties from the subparsec to 100 pc scales. We combine the multifrequency images of J1924–2914 to study the source morphology. We find that the jet exhibits a characteristic bending, with a gradual clockwise rotation of the jet projected position angle of about 90° between 2.3 and 230 GHz. Linearly polarized intensity images of J1924–2914 with the extremely fine resolution of the EHT provide evidence for ordered toroidal magnetic fields in the blazar compact core.
