Abstract
When two black holes merge in a dense star cluster, they form a new black hole with a well-defined mass and spin. If that "second-generation" black hole remains in the cluster, it will continue to participate in dynamical encounters, form binaries, and potentially merge again. Using a grid of 96 dynamical models of dense star clusters and a cosmological model of cluster formation, we explore the production of binary black hole mergers where at least one component of the binary was forged in a previous merger. We create four hypothetical universes where every black hole born in the collapse of a massive star has a dimensionless Kerr spin parameter, χbirth, of 0.0, 0.1, 0.2, or 0.5. We show that if all stellar-born black holes are nonspinning (χbirth=0.0), then more than 10% of merging binary black holes from clusters have components formed from previous mergers, accounting for more than 20% of the mergers from globular clusters detectable by LIGO/Virgo. Furthermore, nearly 7% of detectable mergers would have a component with a mass 55 M, placing it clearly in the mass "gap" region where black holes cannot form from isolated collapsing stars due to the pulsational-pair instability mechanism. On the other hand, if black holes are born spinning, then the contribution from these second-generation mergers decreases, making up as little as 1% of all detections from globular clusters when χbirth=0.5. We make quantitative predictions for the detected masses, mass ratios, and spin properties of first- and second-generation mergers from dense star clusters, and show how these distributions are highly sensitive to the birth spins of black holes.
| Original language | English (US) |
|---|---|
| Article number | 043027 |
| Journal | Physical Review D |
| Volume | 100 |
| Issue number | 4 |
| DOIs | |
| State | Published - Aug 27 2019 |
Fingerprint
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
Cite this
}
Black holes : The next generation - Repeated mergers in dense star clusters and their gravitational-wave properties. / Rodriguez, Carl L.; Zevin, Michael; Amaro-Seoane, Pau; Chatterjee, Sourav; Kremer, Kyle; Rasio, Frederic A.; Ye, Claire S.
In: Physical Review D, Vol. 100, No. 4, 043027, 27.08.2019.Research output: Contribution to journal › Article
TY - JOUR
T1 - Black holes
T2 - The next generation - Repeated mergers in dense star clusters and their gravitational-wave properties
AU - Rodriguez, Carl L.
AU - Zevin, Michael
AU - Amaro-Seoane, Pau
AU - Chatterjee, Sourav
AU - Kremer, Kyle
AU - Rasio, Frederic A.
AU - Ye, Claire S.
PY - 2019/8/27
Y1 - 2019/8/27
N2 - When two black holes merge in a dense star cluster, they form a new black hole with a well-defined mass and spin. If that "second-generation" black hole remains in the cluster, it will continue to participate in dynamical encounters, form binaries, and potentially merge again. Using a grid of 96 dynamical models of dense star clusters and a cosmological model of cluster formation, we explore the production of binary black hole mergers where at least one component of the binary was forged in a previous merger. We create four hypothetical universes where every black hole born in the collapse of a massive star has a dimensionless Kerr spin parameter, χbirth, of 0.0, 0.1, 0.2, or 0.5. We show that if all stellar-born black holes are nonspinning (χbirth=0.0), then more than 10% of merging binary black holes from clusters have components formed from previous mergers, accounting for more than 20% of the mergers from globular clusters detectable by LIGO/Virgo. Furthermore, nearly 7% of detectable mergers would have a component with a mass 55 M, placing it clearly in the mass "gap" region where black holes cannot form from isolated collapsing stars due to the pulsational-pair instability mechanism. On the other hand, if black holes are born spinning, then the contribution from these second-generation mergers decreases, making up as little as 1% of all detections from globular clusters when χbirth=0.5. We make quantitative predictions for the detected masses, mass ratios, and spin properties of first- and second-generation mergers from dense star clusters, and show how these distributions are highly sensitive to the birth spins of black holes.
AB - When two black holes merge in a dense star cluster, they form a new black hole with a well-defined mass and spin. If that "second-generation" black hole remains in the cluster, it will continue to participate in dynamical encounters, form binaries, and potentially merge again. Using a grid of 96 dynamical models of dense star clusters and a cosmological model of cluster formation, we explore the production of binary black hole mergers where at least one component of the binary was forged in a previous merger. We create four hypothetical universes where every black hole born in the collapse of a massive star has a dimensionless Kerr spin parameter, χbirth, of 0.0, 0.1, 0.2, or 0.5. We show that if all stellar-born black holes are nonspinning (χbirth=0.0), then more than 10% of merging binary black holes from clusters have components formed from previous mergers, accounting for more than 20% of the mergers from globular clusters detectable by LIGO/Virgo. Furthermore, nearly 7% of detectable mergers would have a component with a mass 55 M, placing it clearly in the mass "gap" region where black holes cannot form from isolated collapsing stars due to the pulsational-pair instability mechanism. On the other hand, if black holes are born spinning, then the contribution from these second-generation mergers decreases, making up as little as 1% of all detections from globular clusters when χbirth=0.5. We make quantitative predictions for the detected masses, mass ratios, and spin properties of first- and second-generation mergers from dense star clusters, and show how these distributions are highly sensitive to the birth spins of black holes.
UR - http://www.scopus.com/inward/record.url?scp=85072173380&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85072173380&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.100.043027
DO - 10.1103/PhysRevD.100.043027
M3 - Article
AN - SCOPUS:85072173380
VL - 100
JO - Physical Review D
JF - Physical Review D
SN - 2470-0010
IS - 4
M1 - 043027
ER -