Optical properties of variable radio sources from NVSS and FIRST

We have carried out a number of studies to reveal radio properties of active galaxies, namely AGN and Starbursts. A major work was related to the cross-correlation of NVSS and FIRST radio catalogues and revelation of variable radio sources. Most probably, most of them are extragalactic ones; AGN and Starbursts. We have carried out spectroscopic classification of 6301 of these objects and revealed many Seyferts, LINERs and Starbursts. We have also studied radio properties of VCV-13 AGN, Markarian galaxies and Blazars. One of the aims of our studies is to establish the radio/opt flux ratio limit between normal galaxies detected in radio and radio loud active galaxies. The ultimate goal of these studies is to combine results obtained from radio studies and derived radio properties of active galaxies with gammaray, X-ray, UV, optical, IR and submm/mm to have the overall multiwavelength understanding on these objects.