The Event Horizon Telescope Image of the Quasar NRAO 530
Authors: Jorstad Svetlana , Wielgus Maciek , Lico Rocco , Issaoun Sara , Broderick Avery E. , Pesce Dominic W. , Liu 刘 Jun 俊 , Zhao Guang-Yao , Krichbaum Thomas P. , Blackburn Lindy , Chan Chi-kwan , Janssen Michael , Ramakrishnan Venkatessh , Akiyama Kazunori , Alberdi Antxon , Algaba Juan Carlos , Bouman Katherine L. , Cho Ilje , Fuentes Antonio , Gómez José L. , Gurwell Mark , Johnson Michael D. , Kim Jae-Young , Lu 路 Ru-Sen 如森 , Martí-Vidal Iván , Moscibrodzka Monika , Pötzl Felix M. , Traianou Efthalia , van Bemmel Ilse , Alef Walter , Anantua Richard , Asada Keiichi , Azulay Rebecca , Bach Uwe , Baczko Anne-Kathrin , Ball David , Baloković Mislav , Barrett John , Bauböck Michi , Benson Bradford A. , Bintley Dan , Blundell Raymond , Bower Geoffrey C. , Boyce Hope , Bremer Michael , Brinkerink Christiaan D. , Brissenden Roger , Britzen Silke , Broguiere Dominique , Bronzwaer Thomas , Bustamante Sandra , Byun Do-Young , Carlstrom John E. , Ceccobello Chiara , Chael Andrew , Chatterjee Koushik , Chatterjee Shami , Chen Ming-Tang , Chen 陈 Yongjun 永军 , Cheng Xiaopeng , Christian Pierre , Conroy Nicholas S. , Conway John E. , Cordes James M. , Crawford Thomas M. , Crew Geoffrey B. , Cruz-Osorio Alejandro , Cui 崔 Yuzhu 玉竹 , Davelaar Jordy , De Laurentis Mariafelicia , Deane Roger , Dempsey Jessica , Desvignes Gregory , Dexter Jason , Dhruv Vedant , Doeleman Sheperd S. , Dougal Sean , Dzib Sergio A. , Eatough Ralph P. , Emami Razieh , Falcke Heino , Farah Joseph , Fish Vincent L. , Fomalont Ed , Ford H. Alyson , Fraga-Encinas Raquel , Freeman William T. , Friberg Per , Fromm Christian M. , Galison Peter , Gammie Charles F. , García Roberto , Gentaz Olivier , Georgiev Boris , Goddi Ciriaco , Gold Roman , Gómez-Ruiz Arturo I. , Gu 顾 Minfeng 敏峰 , Hada Kazuhiro , Haggard Daryl , Haworth Kari , Hecht Michael H. , Hesper Ronald , Heumann Dirk , Ho 何 Luis C. 子山 , Ho Paul , Honma Mareki , Huang Chih-Wei L. , Huang 黄 Lei 磊 , Hughes David H. , Ikeda Shiro , Impellizzeri C. M. Violette , Inoue Makoto , James David J. , Jannuzi Buell T. , Jeter Britton , Jiang 江 Wu 悟 , Jiménez-Rosales Alejandra , Joshi Abhishek V. , Jung Taehyun , Karami Mansour , Karuppusamy Ramesh , Kawashima Tomohisa , Keating Garrett K. , Kettenis Mark , Kim Dong-Jin , Kim Jongsoo , Kim Junhan , Kino Motoki , Koay Jun Yi , Kocherlakota Prashant , Kofuji Yutaro , Koyama Shoko , Kramer Carsten , Kramer Michael , Kuo Cheng-Yu , La Bella Noemi , Lauer Tod R. , Lee Daeyoung , Lee Sang-Sung , Leung Po Kin , Levis Aviad , Li 李 Zhiyuan 志远 , Lindahl Greg , Lindqvist Michael , Lisakov Mikhail , Liu Kuo , Liuzzo Elisabetta , Lo Wen-Ping , Lobanov Andrei P. , Loinard Laurent , Lonsdale Colin J. , MacDonald Nicholas R. , Mao 毛 Jirong 基荣 , Marchili Nicola , Markoff Sera , Marrone Daniel P. , Marscher Alan P. , Matsushita Satoki , Matthews Lynn D. , Medeiros Lia , Menten Karl M. , Michalik Daniel , Mizuno Izumi , Mizuno Yosuke , Moran James M. , Moriyama Kotaro , Müller Cornelia , Mus Alejandro , Musoke Gibwa , Myserlis Ioannis , Nadolski Andrew , Nagai Hiroshi , Nagar Neil M. , Nakamura Masanori , Narayan Ramesh , Narayanan Gopal , Natarajan Iniyan , Nathanail Antonios , Fuentes Santiago Navarro , Neilsen Joey , Neri Roberto , Ni Chunchong , Noutsos Aristeidis , Nowak Michael A. , Oh Junghwan , Okino Hiroki , Olivares Héctor , Ortiz-León Gisela N. , Oyama Tomoaki , Özel Feryal , Palumbo Daniel C. M. , Paraschos Georgios Filippos , Park Jongho , Parsons Harriet , Patel Nimesh , Pen Ue-Li , Piétu Vincent , Plambeck Richard , PopStefanija Aleksandar , Porth Oliver , Prather Ben , Preciado-López Jorge A. , Psaltis Dimitrios , Pu Hung-Yi , Rao Ramprasad , Rawlings Mark G. , Raymond Alexander W. , Rezzolla Luciano , Ricarte Angelo , Ripperda Bart , Roelofs Freek , Rogers Alan , Ros Eduardo , Romero-Cañizales Cristina , Roshanineshat Arash , Rottmann Helge , Roy Alan L. , Ruiz Ignacio , Ruszczyk Chet , Rygl Kazi L. J. , Sánchez Salvador , Sánchez-Argüelles David , Sánchez-Portal Miguel , Sasada Mahito , Satapathy Kaushik , Savolainen Tuomas , Schloerb F. Peter , Schonfeld Jonathan , Schuster Karl-Friedrich , Shao Lijing , Shen 沈 Zhiqiang 志强 , Small Des , Sohn Bong Won , SooHoo Jason , Souccar Kamal , Sun 孙 He 赫 , Tazaki Fumie , Tetarenko Alexandra J. , Tiede Paul , Tilanus Remo P. J. , Titus Michael , Torne Pablo , Trent Tyler , Trippe Sascha , Turk Matthew , van Langevelde Huib Jan , van Rossum Daniel R. , Vos Jesse , Wagner Jan , Ward-Thompson Derek , Wardle John , Weintroub Jonathan , Wex Norbert , Wharton Robert , Wiik Kaj , Witzel Gunther , Wondrak Michael F. , Wong George N. , Wu 吴 Qingwen 庆文 , Yamaguchi Paul , Yoon Doosoo , Young André , Young Ken , Younsi Ziri , Yuan 袁 Feng 峰 , Yuan 袁 Ye-Fei 业飞 , Zensus J. Anton , Zhang Shuo , Zhao 赵 Shan-Shan 杉杉 
Published: February 2023

Abstract
We report on the observations of the quasar NRAO 530 with the Event Horizon Telescope (EHT) on 2017 April 5−7, when NRAO 530 was used as a calibrator for the EHT observations of Sagittarius A*. At z = 0.902, this is the most distant object imaged by the EHT so far. We reconstruct the first images of the source at 230 GHz, at an unprecedented angular resolution of ∼20 μas, both in total intensity and in linear polarization (LP). We do not detect source variability, allowing us to represent the whole data set with static images. The images reveal a bright feature located on the southern end of the jet, which we associate with the core. The feature is linearly polarized, with a fractional polarization of ∼5%–8%, and it has a substructure consisting of two components. Their observed brightness temperature suggests that the energy density of the jet is dominated by the magnetic field. The jet extends over 60 μas along a position angle ∼ −28°. It includes two features with orthogonal directions of polarization (electric vector position angle), parallel and perpendicular to the jet axis, consistent with a helical structure of the magnetic field in the jet. The outermost feature has a particularly high degree of LP, suggestive of a nearly uniform magnetic field. Future EHT observations will probe the variability of the jet structure on microarcsecond scales, while simultaneous multiwavelength monitoring will provide insight into the high-energy emission origin.