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Variability and Velocity of Superluminal Sources,
M.H. Cohen,
M. Russo,
D.C. Homan,
K.I. Kellermann,
M.L. Lister,
R.C. Vermeulen,
E. Ros,
J.A. Zensus
Radio Astronomy at the Fringe,
J.A. Zensus, M.H. Cohen, E. Ros (eds.)
ASP Conference Series, in press (2003)
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- Abstract
We investigate the relation between the Doppler factor determined
from variations in total flux at 22 and 37 GHz, and the apparent
transverse velocity determined from VLBA observations at 2 cm. The
data are consistent with the relativistic beaming theory for compact
radio sources, in that the distribution of betaapp/deltavar,
for 30 quasars, is roughly consistent with a Monte Carlo simulation.
The intrinsic temperature appears to be ~2x1010 K, close
to the ``equipartition value" calculated by Readhead (1994). We deduce
the distribution of Lorentz factors for a group of 48 sources; the values
range up to about gamma=40.
Eduardo Ros
ros@mpifr-bonn.mpg.de