Name of the Speaker(s): Chris Impey
Institution: Steward Observatory, University of Arizona
Title of the communication:
Quasars and Blazars Across the Electromagnetic Spectrum
Preliminary abstract (12 lines max.):
A statistical analysis of 1 Jy radio sources shows that compact radio emission is
correlated with evidence of strong synchrotron emission at far infrared and optical
wavelengths. Soft X-rays originate in a different spectral component. The apparent
fraction of highly polarized quasars diminishes with increasing redshift, due simply
to dilution from the component believed to be a high temperature accretion disk,
redshifted to optical wavelengths. BL Lac objects are systematically missing this
hot component. These results are consistent with the same bulk relativistic Lorentz
factor for emission at radio and optical wavelengths. Radio sources detected in
gamma rays by EGRET are mostly blazars with strong radio emission and evidence for
bulk relativistic motion. The mechanism for upscattering photons to gamma ray
energies is still uncertain, since the EGRET detections are not notably compact
in their radio emission. Flat spectrum radio sources contribute around 50% of the
diffuse gamma ray background.