A TESS view of Galactic Bulge X-ray sources

Synopsis

The Chandra Galactic Bulge Survey (GBS) is a multi-wavelength survey that includes X-ray, infrared and optical imaging of a 12 square degrees area towards the Galactic Bulge. The GBS was designed to detect both X-ray sources and their optical/infrared counterparts to allow their classification based on multi-wavelength photometric and spectroscopic observations. The GBS X-ray source catalog consists of 1640 unique X-ray sources with candidate optical counterparts to 1480 of them. Of these, 584 are saturated sources. having r’ < 17, i’ < 16. This sample is bright enough to be detected with a large variety of astronomical facilities.

Thus, we search for new variable counterparts detected by the Optical Gravitational Lensing Experiment (OGLE,) and the Transient Exoplanet Survey Satellite (TESS). We identify 20 counterparts in the OGLE public data releases. We extracted and analyzed light curves of the total of 80 GBS sources observed by TESS to identify 6 new variable objects. The optical and X-ray luminosities of the new sources confirm in large degree with that expected from foreground chromospheric active objects such as contact binaries.