The Galactic distribution of X-ray binaries and its implications for compact object formation and natal kicks

Understand

The aim of this work is to study the imprints that different models for black hole (BH) and neutron star (NS) formation have on the Galactic distribution of X-ray binaries (XRBs) which contain these objects.

• We find that the root mean square of the height above the Galactic plane of BH- and NS-XRBs is a powerful proxy to discriminate among different formation scenarios, and that binary evolution following the BH/NS formation does not significantly affect the Galactic distributions of the binaries.
• We find that a population model in which at least some BHs receive a (relatively) high natal kick fits the observed BH-XRBs best.
• For the NS case, we find that a high NK distribution, consistent with the one derived from the measurement of pulsar proper motion, is the most preferable.