Eccentric Black Hole Mergers Forming in Globular Clusters

By J. Samsing. 2017

201 citations recorded by the source corpus.

We derive the probability for a newly formed binary black hole (BBH) to undergo an eccentric gravitational wave (GW) merger during binary-single interactions inside a stellar cluster. By integrating over the hardening interactions such a BBH must undergo before ejection, we find that the observable rate of BBH mergers with eccentricity $>0.1$ at $10\ \rm{Hz}$ relative to the rate of circular mergers can be as high as $\sim 5\%$ for a typical globular cluster (GC). This further suggests that BBH mergers forming through GW captures in binary-single interactions, eccentric or not, are likely to constitute $\sim 10\%$ of the total BBH merger rate from GCs. Such GW capture mergers can only be probed with an $N$-body code that includes General Relativistic corrections, which explains why several recent cluster studies report an eccentric merger rate that is $\sim 100$ times too low. Finally, we show that the relative rate of eccentric BBH mergers depends on the compactness of their host cluster, suggesting that an observed eccentricity distribution can be used to probe the origin of BBH mergers.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b0ce63d8eea58c9a6ef433bc31bed8d5bbb5b0da

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Citations in the corpus

Evolutionary roads leading to low effective spins, high black hole masses, and O1/O2 rates for LIGO/Virgo binary black holes (2017, background): “…Chatterjee et al. 2017; Mapelli 2016; Hurley et al. 2016; Rodriguez et al. 2016a; VanLandingham et al. 2016; Askar et al. 2017; Arca-Sedda & Capuzzo-Dolcetta 2019; Samsing 2018; Morawski et al. 2018; Banerjee 2018; Di Carlo et al. 2019; Zevin et al. 2019; Rodriguez et al. 2018; Perna et al. 2019).”
GW190521: Orbital Eccentricity and Signatures of Dynamical Formation in a Binary Black Hole Merger Signal (2020, background): “Theoretical studies robustly predict that ∼5% of binaries that form dynamically in globular clusters will have e 0.110 (e.g., Rodriguez et al. 2018b; Samsing 2018; Samsing et al. 2018; Kremer et al. 2020).”
Merging black holes in young star clusters (2019, background): “The standard version of BSE calculates gravitational-wave energy loss only if the two binary members are closer than 10 R , which has been shown to lead to a serious underestimate of the merger rate of eccentric binaries in dynamical simulations (Samsing 2018).”
Black hole growth through hierarchical black hole mergers in dense star clusters: implications for gravitational wave detections (2018, result): “Hénon’s principle allows us to relate the hardening rate of the binaries to the global properties of their parent cluster, as opposed to the core properties as done in the previous literature (e.g., Gültekin et al. 2004; Antonini & Rasio 2016; D’Orazio & Samsing 2018; Choksi et al. 2018).”
Eccentric Black Hole Mergers in Dense Star Clusters: The Role of Binary–Binary Encounters (2018, background): “Similar to the binary-single interactions studied in Samsing & D’Orazio (2018) and D’Orazio & Samsing (2018), we find these populations of BBHs formed through binary-binary encounters to have eccentricities measurable by LISA.”
Tests of general relativity with the binary black hole signals from the LIGO-Virgo catalog GWTC-1 (2019, unknown): “, [60–63]).”