Speaker
Description
One of the main challenges in understanding stellar-mass black holes is the lack of observational data, since most Galactic black holes have been detected through X-ray outbursts and therefore represent a small and biased sample. To overcome this limitation and accelerate the rate of black hole discovery, the HAWKs project was designed, with Mini-HAWKs serving as its pathfinder.
Mini-HAWKs is a pilot photometric survey covering 50 square degrees of the Northern Galactic Plane, with 400 hours of guaranteed time, currently being carried out with the JAST80 telescope at the Javalambre Astrophysical Observatory. The survey uses three interference filters centred on H$\alpha$, which allow the full width at half maximum (FWHM) and equivalent width of the H$\alpha$ emission line to be recovered photometrically.
We will show how this information can be used to efficiently identify candidate quiescent black holes through colour-colour diagrams and light curves constructed solely from H$\alpha$ measurements. This method relies on the fact that very broad H$\alpha$ emission lines, with FWHM $\gtrsim$ 2200 km s$^{-1}$, are indicative of the strong gravitational fields surrounding compact objects.
This strategy is promising not only for discovering new black holes, but also for identifying a wide range of other stellar populations, such as cataclysmic variables, Mira variables, Wolf-Rayet stars, and other H$\alpha$ emitters, providing valuable data for multiple lines of research. With the survey now underway, we present the photometric analysis of the first complete Mini-HAWKs fields and discuss the first candidate populations identified from these data.