The parsec-scale evolution of the superluminal quasar 1642+690.
Abstract
We present the results of a 6 cm VLBI monitoring program of the core dominated, radio loud quasar 1642+690. 3.6 cm VLBI observations are also presented. The 6 cm observations, carried out in 1986.4, 1988.2, 1992.2 and 1994.7 confirm that the source is variable, both in morphology and in flux density, its changes reflecting a complicated evolution. We propose a few evolutionary scenarios, and favour the interpretation of the superluminal character of 1642+690, with a flow of superluminal components ejected from the core at a very similar high apparent speed, β_app_~9, in agreement with the first claim of superluminal motion in this source.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1997
- Bibcode:
- 1997A&A...325..484V
- Keywords:
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- GALAXIES: ACTIVE;
- QUASARS: GENERAL;
- RADIO CONTINUUM: GALAXIES;
- QUASARS: INDIVIDUAL: Q 1642+690