Can I read Compact Binary Formation in Open Star Clusters III: Probability of Binary Black Holes Hidden in Gaia Black Hole Binary on EtoBox?

Compact Binary Formation in Open Star Clusters III: Probability of Binary Black Holes Hidden in Gaia Black Hole Binary by Tanikawa, Ataru; Wang, Long; Fujii, Michiko S.; Trani, Alessandro A.; Hayashi, Toshinori; Suto, Yasushi is a scholarly article available to read on EtoBox.

What is Compact Binary Formation in Open Star Clusters III: Probability of Binary Black Holes Hidden in Gaia Black Hole Binary about?

The Gaia mission and its follow-up observations have discovered a few candidates of non-interacting single black holes (BHs) and visible stars: Gaia BH1, BH2, and BH3. We call them ``astrometric BH binaries'' collectively. This paper addresses the question if some of these candidates may indeed harbor binary BHs (BBHs), namely, they may be ``astrometric BBH triples'' that have not been discovered yet. We focus on open star clusters, one of the promising formation sites of astrometric BH binaries, and estimate the formation rate of such astrometric BBH triples using gravitational $N$-body simulations. We find that formation efficiency of astrometric BBH triples is fairly high if they are in low-metallicity environments; $\sim 10^{-6} {\rm M}_\odot^{-1}$ or $\sim 10$ \% of astrometric BH binaries. On the other hand, no such astrometric BBH triple is formed in the solar-metallicity environments. Most of the astrometric BBH triples in our simulations turn out to be dynamically stable for $10$ Gyrs, indicating that $\sim 10$ \% of astrometric BH binary candidates may indeed harbor inner BBHs if they originate from open star clusters in low-metallicity environments. Astrometric BBH tripl

Author

Tanikawa, Ataru; Wang, Long; Fujii, Michiko S.; Trani, Alessandro A.; Hayashi, Toshinori; Suto, Yasushi

Published

2024

Language

EN