A publishing partnership

Space VLBI Observations Show Tb > 1012 K in the Quasar NRAO 530

and

Published 1998 September 28 © 1998. The American Astronomical Society. All rights reserved. Printed in U.S.A.
, , Citation Geoffrey C. Bower and Donald C. Backer 1998 ApJ 507 L117 DOI 10.1086/311701

1538-4357/507/2/L117

Abstract

We present here space-based VLBI observations with VLBI Space Observatory Program (VSOP) and a southern hemisphere ground array of the gamma-ray blazar NRAO 530 at 1.6 and 5 GHz. The brightness temperature of the core at 1.6 GHz is 5×1011 K. The size is near the minimum observable value in the direction of NRAO 530 due to interstellar scattering. The 5 GHz data show a single component with a brightness temperature of ~3×1012 K, significantly in excess of the inverse Compton limit and of the equipartition brightness temperature limit. This is strong evidence for relativistic motion in a jet requiring model-dependent Doppler boosting factors in the range 6-60. We show that a simple homogeneous sphere probably does not model the emission region accurately. We favor instead an inhomogeneous jet model with a Doppler boosting factor of 15.

Export citation and abstract BibTeX RIS

Please wait… references are loading.
10.1086/311701