Optical Counterparts to the X-ray Sources in the Galactic Bulge

We present a sample of 209 variable objects - very likely optical counterparts to the X-ray sources detected in the direction of the Galactic center by the Galactic Bulge Survey, (GBS), carried out with the Chandra satellite. The variable sources were found in the databases of the OGLE long term survey monitoring regularly the Galactic bulge since 1992. The counterpart candidates were searched based on the X-ray source position in the radius of 3."9.

Optical light curves of the candidates comprise a full variety of variability types: spotted stars, pulsating red giants (potentially secondary stars of symbiotic variables), cataclysmic variables, eclipsing binary systems, irregular non-periodic objects including an AGN (GRS 1734-292).

Spotted stars Pulsating red giants Eclipsing and periodic stars
Irregular variables Cataclysmic variables

Additionally, we find that positions of 19 non-variable stars brighter than 16.5~mag in the OGLE databases are so well aligned with the X-ray positions (<0."75) that these objects are also likely optical counterparts to the GBS X-ray sources.

We provide the OGLE astrometric and photometric information for all selected objects and their preliminary classifications. Photometry of the candidates is available from the OGLE Internet archive.

PLEASE cite the following paper when using the data or referring to these OGLE results:
Udalski, Kowalczyk, Soszynski et al., 2012, Acta Astron., 62, 133 (arXiv:1208.0369)

Any comments about the data and the form of their presentation are welcome as they can improve the future releases of OGLE astrometric catalogs. Send your messages to this address.