Abstract
With the growing number of binary black hole (BBH) mergers detected by LIGO/Virgo/KAGRA, several systems have become difficult to explain via isolated binary evolution, having components in the pair-instability mass gap, high orbital eccentricities, and/or spin-orbit misalignment. Here we focus on GW191109_010717, a BBH merger with component masses of 65 − 11 + 11 and 47 − 13 + 15 M ⊙ and an effective spin of − 0.29 − 0.31 + 0.42 , which could imply a spin-orbit misalignment of more than π/2 rad for at least one of its components. Besides its component masses being in the pair-instability mass gap, we show that isolated binary evolution is unlikely to reproduce the proposed spin-orbit misalignment of GW191109 with high confidence. On the other hand, we demonstrate that BBHs dynamically assembled in dense star clusters would naturally reproduce the spin-orbit misalignment and masses of GW191109 and the rates of GW191109-like events if at least one of the components were to be a second-generation BH. Finally, we generalize our results to all events with a measured negative effective spin, arguing that GW200225 also has a likely dynamical origin.
| Original language | English (US) |
|---|---|
| Article number | 23 |
| Journal | Astrophysical Journal |
| Volume | 954 |
| Issue number | 1 |
| DOIs | |
| State | Published - Sep 1 2023 |
Funding
We thank Fred Rasio, Salvatore Vitale, and Katerina Chatziioannou for useful comments on an earlier version of the manuscript. G.F. acknowledges support from NASA grant 80NSSC21K1722. C.K. is grateful for support from the Riedel Family Fellowship in Data Science in CIERA. V.K. was partially supported through a CIFAR Senior Fellowship and by Northwestern University, through the Daniel I. Linzer Distinguished University Professorship fund.
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science