Spatial and Binary Parameter Distributions of Black Hole Binaries in the Milky Way Detectable with Gaia

Understand

Soon after the Gaia data release (DR) 3 in June 2022, some candidates (and one confirmed) of detached black hole (BH) - luminous companion (LC) binaries have been reported.

• Existing and future detections of astrometric BH-LC binaries will shed light on the spatial distribution of these systems, which can deepen our understanding of the natal kicks and the underlying formation mechanism of BHs.
• By tracking Galactic orbits of BH-LC binaries obtained from BSE, we find that distributions of BH mass and the height from the Galactic plane |z| would help us give a constraint on supernova model.
• We also indicate that the correlations of (i) orbital periods and eccentricities, and (ii) BH mass and $|z|$ could be clues for the strength of natal kick, and that the correlations of ($P$, $Z/Z_\odot$) may tell us a clue for common envelope (CE) efficiency.