1998/09/16 by Geoffrey C. Bower, D. C. Backer, Donald C. Backer · 3 citations
Engineering · Physics and Astronomy · #Astrophysics #Astrophysics and Cosmic Phenomena #Galaxy #Particle Accelerators and Free-Electron Lasers #Physics #Quasar #Radio Astronomy Observations and Technology #Very-long-baseline interferometry #astro-ph
paper · pdf · doi:10.1086/311701
12 pages, 2 figures. Accepted for publication in ApJ Letters
arxiv created 1998/09/16 · openalex publication_date 1998/11/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 × 10 11 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 × 10 12 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.