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Session 31 - Quasars.
Oral session, Wednesday, January 07
International Ballroom East,
Quantitative comparisons of the extended radio emission of quasars is complicated by several factors: the strong dependence of surface brightness on redshift; differences in rest-frame resolution due to redshift and instrumental beam size; and observing frequency. We have accounted for these effects by adjusting maps of lower redshift quasars to have the same rest-frame physical resolution and limiting surface brightness as a higher redshift comparison. A sample of 25 quasars drawn from the Large Bright Quasar Survey (LBQS) radio studies (e.g., Hooper et al. 1996, ApJ, 473, 746) has been mapped with 0.25 arcsecond resolution at the VLA. The LBQS sample, which covers a redshift range 0.4 < 3.4, is being compared to the predominantly lower redshift Palomar-Green Bright Quasar Survey, as well as other samples with high-resolution radio maps. The physical size of the extended components and the ratio of core to extended flux are measured after incorporating the adjustments mentioned above. These parameters are helping to determine the evolution of quasar radio properties as well as the effects of different selection criteria in the original surveys.
