Classification of Optical Transients: Experiences from PQ and CRTS Surveys

Synoptic sky surveys are opening up exciting opportunities in time domain astronomy. Gaia will make a great contribution to this field. A crucial factor for good scientific returns is real-time classification of transients, in order to optimize their follow-up. We have been developing infrastructure towards this end starting from the completed Palomar-Quest (PQ) survey, and the ongoing Catalina Real-Time Transient Survey (CRTS). CRTS has been consistently producing transients for almost three years now. We describe here the efforts related to transient classification and event dissemination. Many of the technologies and methodologies we are developing may benefit Gaia.