The Event Horizon Telescope Image of the Quasar NRAO 530

Svetlana Jorstad*, Maciek Wielgus, Rocco Lico, Sara Issaoun, Avery E. Broderick, Dominic W. Pesce, Jun Liu, Guang Yao Zhao, Thomas P. Krichbaum, Lindy Blackburn, Chi Kwan Chan, Michael Janssen, Venkatessh Ramakrishnan, Kazunori Akiyama, Antxon Alberdi, Juan Carlos Algaba, Katherine L. Bouman, Ilje Cho, Antonio Fuentes, José L. GómezMark Gurwell, Event Horizon Telescope Collaboration

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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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.

Original languageEnglish
Article number170
Number of pages19
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 1 Feb 2023
MoE publication typeA1 Journal article-refereed


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