Radio Galaxies in Abell Rich Clusters

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Session 17 -- Radio Galaxies and High Luminosity AGNs
Oral presentation, Monday, 30, 1994, 10:00-11:30

[17.02] Radio Galaxies in Abell Rich Clusters


We have defined a complete sample of radio galaxies chosen from Abell's northern catalog consisting of all clusters with measured redshifts $< 0.09$. This sample consists of nearly 300 clusters. A multiwavelength survey including optical CCD R-Band imaging, optical spectroscopy, and VLA 20 cm radio maps has been compiled. I have used this database to study the optical/radio properties of radio galaxies in the cluster environment. In particular, optical properties have been compared to a radio-quiet selected sample to look for optical signatures which may distinguish radio galaxies from normal radio-quiet ellipticals. The correlations between radio morphology and galaxy type, the optical dependence of the {\sl FR I/II} break, and the univariate and bivariate luminosity functions have been examined for this sample. This study is aimed at understanding radio galaxies as a population and examining their status in the AGN heirarchy. The results of this work will be applied to models of radio source evolution.

The results from the optical data analysis suggest that radio galaxies, as a class, cannot be distinguished from non-radio selected elliptical galaxies. The magnitude/size relationship, the surface-brightness profiles, the fundamental plane, and the intrinsic shape of the radio galaxies are consistent between our radio galaxy and control sample. The radio galaxies also trace the elliptical galaxy optical luminosity function in clusters very well; with many more $L^*$ galaxies than brightest cluster members. Combined with the results of the spectroscopy, the data are consistent with the idea that all elliptical galaxies may at some point in their lifetimes become radio sources.

In conclusion, I present a new observational picture for radio galaxies and discuss the important properties which may determine the evolution of individual sources.

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