Discovery of a Compact X-Ray Object with a 614 s Periodicity in the Direction of the Galactic Center

We report on analysis of X-ray, optical, and radio observations of the previously overlooked X-ray source 2CXO J174517.0-321356 located just 3.°2 away from the Galactic center. Timing analysis of X-ray observations of the source with XMM-Newton reveals periodic pulsations with periods of 1228 and 614 s, with the latter being tentatively considered fundamental. On the other hand, an observation of the object with NuSTAR reveals a hard thermal-bremsstrahlung spectrum. Inspection of the archival Very Large Telescope image reveals, however, no obvious optical counterpart down to R > 25 mag. Observations made with ATCA showed a possible faint radio counterpart with a positive spectral index (α > 0.51) between 1 and 3 GHz, but follow-up ATCA and Very Large Array observations at frequencies between 4.5-10 GHz and 3-22 GHz, respectively, could not detect it. Given the properties in these three bands, we argue that the most likely origin of the X-ray source is emission from a new intermediate polar close to the Galactic center. Alternatively, and less likely, it is an ultracompact X-ray binary, which is one of the most compact X-ray binaries.