Detection of X-Ray Periodicity from a New Eclipsing Polar Candidate XGPS-I J183251-100106

We report the results from a detailed analysis of an archival XMM-Newton observation of the X-ray source XGPS-I J183251-100106, which has been suggested as a promising magnetic cataclysmic variable (CV) candidate based on its optical properties. A single periodic signal of ~1.5 hr is detected from all EPIC instruments on board XMM-Newton. The phase-averaged X-ray spectrum can be well modeled with a thermal bremsstrahlung temperature of kT ~ 50 keV. Both the X-ray spectral and temporal behavior of this system suggest that it is an eclipsing CV of the AM Herculis (or polar) type.