Deep MMT1 transit survey of the open cluster M37.: II.: Variable stars

We have conducted a deep (15 less than or similar to r less than or similar to 23), 20 night survey for transiting planets in the intermediate-age (similar to 550 Myr) open cluster M37 (NGC 2099) using the Megacam wide-field mosaic CCD camera on the 6.5 m MMT. In this paper we present a catalog and light curves for 1445 variable stars; 1430 (99%) of these are new discoveries. We have discovered 20 new eclipsing binaries and 31 new short-period (P < 1 day) pulsating stars. The bulk of the variables are most likely rapidly rotating young low-mass stars, including a substantial number (greater than or similar to 500) that are members of the cluster. We identify and analyze five particularly interesting individual variables, including a previously identified variable that we suggest is probably a hybrid gamma Doradus/delta Scuti pulsator, two possible quiescent cataclysmic variables, a detached eclipsing binary (DEB) with at least one gamma Doradus pulsating component (only the second such variable found in an eclipsing binary), and a low-mass (M-P similar to M-S similar to 0.6 M-circle dot) DEB that is a possible cluster member. A preliminary determination of the physical parameters for the DEB+gamma Doradus system yields M-P = 1.58 +/- 0.04 M-circle dot, M-S = 1.58 +/- 0.04 M-circle dot, R-P = 1.39 +/- 0.07 R-circle dot, and R-S = 1.38 +/- 0.07 R-circle dot.