Resolving the inner JET structure of 1924-292 with the event horizon telescope

Ru Sen Lu, Vincent L. Fish, Jonathan Weintroub, Sheperd S. Doeleman, Geoffrey C. Bower, Robert Freund, Per Friberg, Paul T.P. Ho, Mareki Honma, Makoto Inoue, Thomas P. Krichbaum, Daniel P. Marrone, James M. Moran, Tomoaki Oyama, Richard Plambeck, Rurik Primiani, Zhi Qiang Shen, Remo P.J. Tilanus, Melvyn Wright, Ken H. YoungLucy M. Ziurys, J. Anton Zensus

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


We present the first 1.3mm (230GHz) very long baseline interferometry model image of an active galactic nucleus (AGN) jet using closure phase techniques with a four-element array. The model image of the quasar 1924-292 was obtained with four telescopes at three observatories: the James Clerk Maxwell Telescope on Mauna Kea in Hawaii, the Arizona Radio Observatory's Submillimeter Telescope in Arizona, and two telescopes of the Combined Array for Research in Millimeter-wave Astronomy in California in 2009 April. With the greatly improved resolution compared with previous observations and robust closure phase measurement, the inner jet structure of 1924-292 was spatially resolved. The inner jet extends to the northwest along a position angle of -53° at a distance of 0.38mas from the tentatively identified core, in agreement with the inner jet structure inferred from lower frequencies, and making a position angle difference of ∼80° with respect to the centimeter jet. The size of the compact core is 0.15pc with a brightness temperature of 1.2 × 10 11K. Compared with those measured at lower frequencies, the low brightness temperature may argue in favor of the decelerating jet model or particle-cascade models. The successful measurement of closure phase paves the way for imaging and time resolving Sgr A* and nearby AGNs with the Event Horizon Telescope.

Original languageEnglish (US)
Article numberL14
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Sep 20 2012


  • galaxies: active
  • galaxies: jets
  • quasars: individual (1924-292)
  • radio continuum: general
  • techniques: high angular resolution
  • techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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