Speaker
Description
We present a new method to identify candidate quiescent black holes based on optical variability analysis, using data from Mini-HAWKs — a pilot photometric survey currently underway with the JAST80 telescope at the Observatorio de Javalambre.
The Mini-HAWKs strategy exploits a known correlation between the full width at half maximum (FWHM) of H-alpha emission lines and the semi-amplitude of the companion star's projected velocity, established from the 20 Galactic X-ray transients confirmed to host quiescent black holes. When combined with orbital period information, this relation allows the mass function to be reconstructed from photometric data alone, providing a powerful indicator of the compact object's nature without requiring spectroscopy upfront.
With the variability analysis we can also identify other variable sources in the field, such as cataclysmic variables and eclipsing binaries, that could contaminate the quiescent black hole candidate sample. Our method based on variability analysis, complementary to colour–colour analysis, therefore sharpens the selection of the most promising candidates for spectroscopic follow-up, which remains essential for the dynamical confirmation of quiescent black holes.