Radioastron observations of the quasar 3C 273

A challenge to the brightness temperature limit

Journal article (2016)

Authors

Yuri Y. Kovalev Max-Planck-Institute for Radio Astronomy, Lebedev Physical Institute
N. S. Kardashev Lebedev Physical Institute
David L. Jauncey Australian National University
F. Ghigo National Radio Astronomy Observatory
T. Ghosh Arecibo Observatory
A. Kraus Max-Planck-Institute for Radio Astronomy
Yu A. Kovalev Lebedev Physical Institute
Mikhail M. Lisakov Lebedev Physical Institute
L. Yu Petrov Astrogeo Center
J. D. Romney National Radio Astronomy Observatory
C. J. Salter Arecibo Observatory
Kirill V. Sokolovsky Lebedev Physical Institute, Moscow State University
K. I. Kellermann National Radio Astronomy Observatory
A. P. Lobanov Hamburg University of Technology, Max-Planck-Institute for Radio Astronomy
M. D. Johnson Harvard-Smithsonian Center for Astrophysics
L. Gurvits Joint Institute for VLBI ERIC,
Peter A. Voitsik Lebedev Physical Institute
J. A. Zensus Max-Planck-Institute for Radio Astronomy
James M. Anderson VolcanoTectonics Junior Research Group
U. Bach Max-Planck-Institute for Radio Astronomy
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Published Date

20-03-2016

Language

English

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Abstract

Inverse Compton cooling limits the brightness temperature of the radiating plasma to a maximum of 1011.5 K. Relativistic boosting can increase its observed value, but apparent brightness temperatures much in excess of 1013 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 1013 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.