Testing the Inner Binary Scenario in Gaia BH1

In this study, I used high-precision radial velocity (RV) measurements of Gaia BH1, the closest known black hole (BH) system, to update its orbital constraints and investigate whether the massive dark companion is a BH + BH binary rather than a single BH. These observations, which were concentrated near periastron and covered 2.33 orbits of the G star, showed no significant evidence for deviations from a Keplerian orbit. Using REBOUND simulations of hierarchical triples with a range of orbital parameters, mass ratios, and orientations, I showed that inner binaries with orbital periods longer than about 1.5 days would have led to detectable RV perturbations. On the other hand, inner binaries with shorter orbital periods would have merged quickly, implying fine-tuning.

Read more about this research project in the associated publication here.