S E M I N A R IDepartament d'Astronomia i Astrofísica
Universitat de València
Flashing superluminical components in the radio jet of 3CI20
José Luis Gómez
Instituto de Astrofísica de Andalucía
Seminari del Departament
Dimecres 20 desembre 2000
The most thorough study of a relativistic jet to date at ultra-fine linear resolution (0.2 h65-1 pc, where h65 is the Hubble constant in units of 65 km s-1 Mpc-1), reveals a region between 1.5 and 3.5 milliarcseconds from the core of the radio galaxy 3Cl2O where superluminal components flash off and on over timescales of months. This interesting behaviour is caused either by (1) interaction between the underlying hydrodynamical pattern of the jet and the propagating disturbances that are observed as superluminal knots, or (2) obscuration by free-free absortion in emission-line clouds that lie in front of the jet. The first case provides a new paradigm for the interpretation of light curves of active galactic nuclei, whilst the second can explain the curvatura of the jet as well as the observed cross-sectional stratification.