The Astrophysical Journal, vol. 943, no. 2, pp. 170(27pp)

著者:

  • 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. Gómez
  • Mark Gurwell
  • Michael D. Johnson
  • Jae-Young Kim
  • Ru-Sen Lu
  • Iván Mart{'\i}-Vidal
  • Monika Moscibrodzka
  • Felix M. Pötzl
  • Efthalia Traianou
  • Ilse van Bemmel
  • The Event Horizon Telescope Collaboration

URL:

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$^\ast$. 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 230GHz, at an unprecedented angular resolution of $\sim20 µas$, 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 $\sim$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 60µas along a position angle $\sim-28°$. 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.