A New Limit to the Size of the Radio Nucleus of NGC 5128
Abstract
We have measured the size of the compact radio nucleus of the giant radio galaxy Centaurus A (NGC 5128) as 0.5 +/- 0.1 milliarcseconds. The corresponding linear dimensions of 0.01 pc ~ 10 light-days ~ 1016 cm make this the smallest known extragalactic radio source. If the radio lobes are powered by a massive central engine, such as a black hole, their large total energy content combined with our measurement of the size of the central radio source, suggest that the central mass density may have exceeded 5 × 1013 Msolar pc-3, a value far larger than has been determined for any other active galactic nucleus or quasar.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1997
- DOI:
- 10.1086/310469
- Bibcode:
- 1997ApJ...475L..93K
- Keywords:
-
- RADIO CONTINUUM: GALAXIES;
- GALAXIES: NUCLEI;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 5128;
- BLACK HOLE PHYSICS;
- Black Hole Physics;
- Galaxies: Individual: NGC Number: NGC 5128;
- Galaxies: Nuclei;
- Radio Continuum: Galaxies