Pair instabilities in supernovae might prevent the formation of black holes with masses between ∼50 M and ∼130 M. Multiple generations of black-hole mergers provide a possible way to populate this "mass gap" from below. However this requires an astrophysical environment with a sufficiently large escape speed to retain merger remnants, and prevent them from being ejected by gravitational-wave recoils. We show that, if the mass gap is indeed populated by multiple mergers, the observation of a single black-hole binary component in the mass gap implies that its progenitors grew in an environment with escape speed vesc 50 km/s. This is larger than the escape speeds of most globular clusters, requiring denser and heavier environments such as nuclear star clusters or disks-assisted migration in galactic nuclei. A single detection in the upper mass gap would hint at the existence of a much larger population of first-generation events from the same environment, thus providing a tool to disentangle the contribution of different formation channels to the observed merger rate.

Gerosa, D., Berti, E. (2019). Escape speed of stellar clusters from multiple-generation black-hole mergers in the upper mass gap. PHYSICAL REVIEW D, 100(4) [10.1103/PhysRevD.100.041301].

Escape speed of stellar clusters from multiple-generation black-hole mergers in the upper mass gap

Gerosa D;
2019

Abstract

Pair instabilities in supernovae might prevent the formation of black holes with masses between ∼50 M and ∼130 M. Multiple generations of black-hole mergers provide a possible way to populate this "mass gap" from below. However this requires an astrophysical environment with a sufficiently large escape speed to retain merger remnants, and prevent them from being ejected by gravitational-wave recoils. We show that, if the mass gap is indeed populated by multiple mergers, the observation of a single black-hole binary component in the mass gap implies that its progenitors grew in an environment with escape speed vesc 50 km/s. This is larger than the escape speeds of most globular clusters, requiring denser and heavier environments such as nuclear star clusters or disks-assisted migration in galactic nuclei. A single detection in the upper mass gap would hint at the existence of a much larger population of first-generation events from the same environment, thus providing a tool to disentangle the contribution of different formation channels to the observed merger rate.
Articolo in rivista - Articolo scientifico
black holes, gravitational waves, general relativity, relativistic astrophysics
English
2019
100
4
041301
none
Gerosa, D., Berti, E. (2019). Escape speed of stellar clusters from multiple-generation black-hole mergers in the upper mass gap. PHYSICAL REVIEW D, 100(4) [10.1103/PhysRevD.100.041301].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/325538
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