Multiple Outbursts of a Cataclysmic Variable in the Globular Cluster M22

Abstract

We present a 4 year light curve of a cataclysmic variable in M22, based on an analysis of accumulated data from the MOA microlensing survey. The position of the star coincides with that of a transient event observed by HST in 1999, originally attributed to microlensing but later suspected to be a dwarf nova outburst. Two outburst episodes, one in 2002 and one in 2003, with $\Delta I\sim 3$ are seen in the MOA data thus confirming that the HST event was a dwarf nova outburst. The MOA and HST data show that this dwarf nova underwent at least three outburst episodes during 1999--2004. Further close monitoring of this event is encouraged as future outburst episodes are expected.

12 pages, 4 figures, accepted for publication ApJ letters

References in corpus (5)

• A method for optimal image subtraction
• Real-Time Difference Imaging Analysis of MOA Galactic Bulge Observations During 2000
• Optical Identification of Multiple Faint X-ray Sources in the Globular Cluster NGC 6752: Evidence for Numerous Cataclysmic Variables
• Wide Field Photometry of the Galactic Globular Cluster M22
• X-ray sources and their optical counterparts in the globular cluster M 22

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• Near-ultraviolet detections of four dwarf nova candidates in the globular cluster 47 Tucanae
• Ground and space-based study of two globular cluster CVs: M22 CV1 and M5 V101
• Neutron Stars and Black Holes in Star Clusters