DECam Community Science Workshop 2018: Science Highlights, Coming Opportunities, LSST Synergies
May 21-22, 2018 • Tucson, Arizona
We propose to exploit a novel strategy to uncover the Galactic population of quiescent black holes (BHs) in X-ray binaries. This is based on a new concept, the photometric mass function (PMF), which opens up the possibility of an efficient identification of dynamical BHs in large FOVs. It exploits the width of the Halpha emission line arising from the accretion disc, to be measured photometrically through a combination of custom Halpha filters. Details of the technique and survey strategy are given in Casares 2018
(MNRAS 473 5195).
We estimate that a dedicated survey of ∼800 deg2 at depth r~22 with three special Halpha filters are required to unveil >∼50 new dynamical BHs, a three-fold improvement over the known population. For comparison, a century would be needed to produce an enlarged sample of 50 dynamical BHs from X-ray transients at the current discovery rate. The survey, which we name HAWKs (after "HAlpha-Width Kilo-deg Survey”) will also deliver a census of other Halpha emitting objects - such as cataclysmic variables, accreting millisecond pulsars, symbiotic binaries, YSOs, etc.- to unprecedented depths. HAWKs will become a unique legacy survey for follow-up studies of Halpha emitting populations in the Galaxy. We estimate that ~100 nights will be required to complete HAWKs.
Authors: Jorge Casares