Name of the Speaker(s): M.K.Babadzhanyants
Institution: Astronomical Institute of St.-Petersburg University, Russia
Title of the communication: The difference between spectral indices of "slow"- and "short"-time optical-IR outbursts of quasar 3C 345.
Preliminary abstract (12 lines max.): Own long-term UBV observations of quasar 3C 345 together with other available optical-IR multibands data were analyzed. It is shown that the sources responsible for f-flares (weeks of duration) have sufficiently flatter spectra than ones responsible for s-flares (nearly 2 yrs of duration). Optical spectral indices: alpha(f)=-0.8 and alpha(s)=-1.7. This difference is one of the reasons for appearance of opposite correlations between observational spectral slope and flux density revealed for 3C 345.