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We study a Chandra X-ray Observatory ACIS-S observation of the Galacticglobular clusterM12. With a 26 ks exposure time, we detect 6 X-ray sourcesinside the half-mass radius (2.16 arcminutes) of which two are inside the coreradius (0.72 arcminutes) of the cluster. If we assume these sources are allassociated with globular cluster M12, the luminosity L_{X} among these sourcesbetween 0.3-7.0 keV varies roughly from 10^{30} to 10^{32} ergs s^{-1}. Foridentification, we also analyzed the Hubble Space Telescope (HST) AdvancedCamera for Surveys (ACS) and Wide Field and Planetary Camera 2 (WFPC2) data andidentified the optical counterparts to five X-ray sources inside the HST ACSfield of view. According to the X-ray and optical features, we found 2-5candidate active binaries (ABs) or cataclysmic variables (CVs) and 0-3background galaxies within the HST ACS field of view. Based on the assumptionthat the number of X-ray sources scales with the encounter rate and the mass ofthe globular cluster, we expect 2 X-ray source inside M12, and the expectationis consistent with our observational results. Therefore, the existence ofidentified X-ray sources (possible CVs or ABs) in M12 suggests the primordialorigin of X-ray sources in globular clusters which is in agreement withprevious studies.

X-ray Sources and Their Optical Counterparts in the Galactic Globular Cluster M12 (NGC 6218)