A Radial Velocity Survey of Candidate Variable Hot Subdwarfs from Gaia DR2

Over the past few years, ESA's Gaia spacecraft has been obtaining astrometric measurements of more than 1 billion stars with unparalleled precision. The reported Gaia DR2 G magnitudes were determined by combining multiple brightness measurements, with photometric uncertainties being determined empirically. Thus, intrinsically variable sources could have anomalously large uncertainties for their given G magnitude. Leveraging this fact, we have identified more than 1,000 candidate variable hot subdwarfs in Gaia DR2. We have initiated a campaign with the CHIRON spectrograph on the CTIO 1.5-m telescope to monitor the radial velocities of all candidate variable hot subdwarfs with G < 13 mag in the southern hemisphere. We have already identified several new rapid binaries. Here, we discuss the details of this survey and tentative results.