CXB3 is a symbiotic binary star candidate identified by the Galactic Bulge Survey using X-ray observations by the Chandra X-ray Observatory. Using new Chandra observations, we demonstrate X-ray variability CXB3 with observations showing it usually in a quiescent state with a factor-of-six flare-like event in the last observation. Spectra of CXB3 we find are most consistent with thermal emission as seen in white dwarf symbiotic systems but the high X-ray luminosity in the lightcurve is more typically seen in Symbiotic X-ray Binary systems. Optical spectra taken with Gemini GMOS indicate CXB3 as containing an M type star that lacks H-alpha emission, which is unusual for typical symbiotic systems and more favors a symbiotic X-ray binary interpretation for the source.The scientific results reported in this article are based on observations made by the Chandra X-ray Observatory and data obtained from the Chandra Data Archive.

Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Numbers AR5-16004X and AR0-21005X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060.