NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-20 T02:08:23 PDT
Help | Comment | NED Home

For refcode 2000A&A...364..391L:
Retrieve 27 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by European Southern Observatory (ESO). Reproduced by permission
2000A&A...364..391L 86GHz VLBI survey of compact radio sources. LOBANOV A.P., KRICHBAUM T.P., GRAHAM D.A., WITZEL A., KRAUS A., ZENSUS J.A., BRITZEN S., GREVE A., GREWING M. Received 17 September 1999/Accepted 12 October 2000 Abstract: We present results from 86GHz VLBI observations of 28 compact radio sources made in April 1993. All but two of the observed objects are active galactic nuclei. The remaining two objects are the galactic center Sgr A* and the X-ray binary star Cygnus X-3. Of the observed sources, 26 have yielded fringe detections. We present correlated flux densities, estimate the maximum observed brightness temperatures, and provide single Gaussian component model fits. Out of the 17 sources with good uv- coverages, 3 are without detectable structural details (0642+449, 0716+714, and Cygnus A), 3 have little closure phase information (4C67.05, 1823+568, and 1928+738), and the remaining 11 have been imaged. We study the brightness temperatures, Tb, of the observed sources, and apply a basic population model with a single value of the intrinsic brightness temperature, T_0_, in order to reproduce the observed distribution of T_b_. Our data are consistent with a population of sources that have T_0_ <= 5x10^10^K in the jets, and T_0_ ~ 1-4 x 10^11^K in the VLBI cores. The observed T_b_ are also correlated with the apparent speeds measured in the jets. For comparison, we apply the same population scenario to a larger sample of 132 AGN observed with VLBI at 15GHz, and show that the distribution of brightness temperatures from that sample is consistent with the intrinsic brightness temperature of T_0_ = 5.3 x 10^11^K. The observed decrease of T_b_ along the jets can be reproduced by adiabatic losses in relativistic shocks embedded in the jet. Key words: galaxies: active - galaxies: jets - galaxies: nuclei - galaxies: quasars: general - radio continuum: galaxies
Retrieve 27 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home