An Optical Outburst of the Cataclysmic Variable in M22

Cataclysmic variables (CVs) formed through close encounters may be the most abundant class of compact binaries in globular clusters. As part of a systematic search for CVs undergoing dwarf nova eruptions (DN) in globular clusters, our 2004 monitoring program of M22 detected an outburst of a CV candidate during May. We present a light curve for the May 2004 period, obtained using the ISIS image subtraction routine. Our ground based results are in good agreement with previous HST measurements, and confirm the DN nature of the outburst and the object's CV status. Further application of the ISIS software will enable us to identify other DN candidates in the core of M22 with the aim of characterizing the properties of these systems, as opposed to similar ones in the field.