In the study presented here we have extracted a well defined control sample from the radio galaxy fields. While this was a good sample of early-type galaxies, we were hampered in studying certain distance related aspects of these galaxies since we lacked the redshifts to these objects. During the period of the thesis it was not possible to obtain these redshifts. Because of their inherent uncertainties, photometric redshifts would not have served the purpose. An alternative was to choose a different control sample made of early-type galaxies but for which the redshifts are known. However, we would then have lost the advantage of having identical processing for the radio and the control sample.
Taking all the above points into consideration, obtaining photometric redshifts for the control galaxies seems to be the lesser evil and we hope to do that in the near future. That study will also help us examine cluster characteristics and compare the cluster properties of FR I and FR II sources. We will also be able to study the possible relationship between individual galaxies with blue centers and the Butcher-Oemler effect.
In relation to the above point, high resolution spectra of the radio galaxies will allow us to estimate various line strengths and hence metallicities and enable us to model the recent star burst in the radio galaxies (e.g. Leonardi and Rose, 1996). The spectra will also provide information on the nuclear processes.
Recent studies of central regions of elliptical galaxies observed with the HST have indicated that ellipticals can be divided into cuspy galaxies and galaxies with a core ( Crane et al., 1993; Jaffe et al., 1994; Forbes et al., 1995; Faber et al., 1997). Our ground based data does not have the resolution to sample the central parts of galaxies. However, the advantage of the ground based data is that it extends to much larger angular sizes than the HST data. We propose to obtain HST data for our galaxies and combine it with our ground based data to see how the properties we have described here relate to the two types of galaxies. It will also allow us to probe the central regions better and confirm and further quantify the excess blue emission that we have detected. We are thankful to Ken Freeman for the germ of this idea.
Time and again we felt the need of high resolution radio maps when
trying to examine the association between optical and radio features.
Especially interesting would be the possible association of recent star
formation with the radio jets
(e.g. as shown by Best et al., 1996, for 
galaxies),
association of spiral-like structures
in various galaxies with radio enhancements and so on. We plan to
obtain high resolution radio maps of these southern galaxies when VLA is in
the right configuration (A + B).
We have used the morphological gradient filter for detecting disks in galaxies. Initial tests with the morphological top hat filter have indicated that it can be especially good at detecting faint absorption features since it is particularly adapted to finding features ``in shadows''. The top hat and other morphological filters will be studied in detail and calibrated as part of the followup.
Studies have indicated that HI in galaxies is associated with disturbed morphologies (e.g. Schiminovich et al., 1994, 1995). We would like to obtain HI observations for the sample. The Giant Meterwave Radio Telescope (GMRT), near Pune in India, will be able to reach the southern declinations of our sample.