Abstract:
It is well established that blazars show flux variations in the
complete electromagnetic (EM) spectrum on all possible time scales rang-
ing from a few tens of minutes to several years. Here, we report the review
of optical flux and spectral variability properties of different classes of
blazars on IDV and STV time-scales. Our analysis show HSPs are less
variable in optical bands as compared to LSPs. Also, we investigated
the spectral slope variability and found that the average spectral slopes
of LSPs showed a good agreement with the synchrotron self-Compton
loss-dominated model. However, spectra of the HSPs and FSRQs have
significant additional emission components. In general, spectra of BL
Lacs get flatter when they become brighter, while for FSRQs the opposite
trend appears to hold.
