Search for Dwarf Novae in DASCH Scans Near M44

Sumin Tang, Silas Laycock, Jonathan Grindlay, Ye-Fei Yuan, Xiang-Dong Li, Dong Lai
2008 AIP Conference Proceedings  
Dwarf novae (DNe) are a subclass of Cataclysmic Variables (CVs) with outbursts powered by a disk instability leading to a sudden increase in the accretion rate. The Digital Access to a Sky Century at Harvard (DASCH) Collaboration is preparing to digitize over 500,000 Harvard plates from the 1880s to the 1980s with limiting magnitudes ranging from B∼ 14 − 19. As a demonstration project, we have scanned more than 500 plates in the fields centered on the galactic open cluster M44. There are 21 CVs
more » ... in the fields within 10 degrees of M44 covered by the scans. Here we present the preliminary results of DN outbursts of the known CVs to derive long-term DN outburst duty cycles. In addition, a 100y lightcurve for a XMM−Newton source is also presented to demonstrate DASCH capabilities.
doi:10.1063/1.2840410 fatcat:nsxao3c375cojbp6s5imalaqou