Correlation of Color Behaviour of Blazars and Optical Afterglows of GRBs.

It has been demonstrated that the colors of optical afterglows (OAs) of GRBs are unique and almost identical for most of these events detected and analyzed in detail so far. This enables conclusions toward physics of the source and physics of the source environment. In addition, OAs can be identified on CCD images taken at one time but in various filters. In this study, we compare the color behaviour of OAs of GRBs with those of other extragalactic objects. We will show that not only the physical processes involved as well as environment of the objects can be studied this way but also a classification of objects of various types is possible with color photometric data provided e.g. by deep CCD searches and experiments. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]