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Title: RADIOASTRON OBSERVATIONS OF THE QUASAR 3C273: A CHALLENGE TO THE BRIGHTNESS TEMPERATURE LIMIT

Inverse Compton cooling limits the brightness temperature of the radiating plasma to a maximum of 10{sup 11.5} K. Relativistic boosting can increase its observed value, but apparent brightness temperatures much in excess of 10{sup 13} K are inaccessible using ground-based very long baseline interferometry (VLBI) at any wavelength. We present observations of the quasar 3C 273, made with the space VLBI mission RadioAstron on baselines up to 171,000 km, which directly reveal the presence of angular structure as small as 26 μas (2.7 light months) and brightness temperature in excess of 10{sup 13} K. These measurements challenge our understanding of the non-thermal continuum emission in the vicinity of supermassive black holes and require a much higher Doppler factor than what is determined from jet apparent kinematics.
Authors:
; ; ; ; ;  [1] ;  [2] ; ; ; ; ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ; ;  [8] ;  [9] ;  [10]
  1. Astro Space Center of Lebedev Physical Institute, Profsoyuznaya 84/32, 117997 Moscow (Russian Federation)
  2. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States)
  3. Max-Planck-Institute for Radio Astronomy, Auf dem Hügel 69, D-53121 (Germany)
  4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  5. Joint Institute for VLBI ERIC, P.O. Box 2, 7990 AA Dwingeloo (Netherlands)
  6. CSIRO Astronomy and Space Sciences, Epping, NSW 1710 (Australia)
  7. National Radio Astronomy Observatory, Rt. 28/92, Green Bank, WV 24944-0002 (United States)
  8. Arecibo Observatory, NAIC, HC3 Box 53995, Arecibo, Puerto Rico, PR 00612 (United States)
  9. Astrogeo Center, 7312 Sportsman Drive, Falls Church, VA 22043 (United States)
  10. National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801-0387 (United States)
Publication Date:
OSTI Identifier:
22518572
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 820; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; BRIGHTNESS; COOLING; GALAXIES; INTERFEROMETRY; JETS; PLASMA; QUASARS; RELATIVISTIC RANGE; SPACE