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https://hdl.handle.net/2445/220948
Title: | Dynamical formation of Gaia BH3 in the progenitor globular cluster of the ED-2 stream |
Author: | Marín Pina, Daniel Rastello, Sara Gieles, Mark Kremer, Kyle Fitzgerald, Laura Rando Forastier, Bruno |
Keywords: | Forats negres (Astronomia) Halos (Meteorologia) Estels Black holes (Astronomy) Halos (Meteorology) Stars |
Issue Date: | 2024 |
Publisher: | EDP Sciences |
Abstract: | Context. The star–black hole (S–BH) binary known as Gaia BH3, discovered by the Gaia Collaboration is chemically and kinemati-cally associated with the metal-poor ED-2 stream in the Milky Way halo.Aims. We explore the possibility that Gaia BH3 was assembled dynamically in the progenitor globular cluster (GC) of the ED-2stream.Methods. We used a public suite of star-by-star dynamical Monte Carlo models to identify S–BH binaries in GCs with different initialmasses and (half-mass) radii.Results. We show that a likely progenitor of the ED-2 stream was a relatively low-mass (.105 M ) GC with an initial half-massradius of ∼4 pc. Such a GC can dynamically retain a large fraction of its BH population and dissolve on the orbit of ED-2. Fromthe suite of models we find that GCs produce ∼3−30 S–BH binaries, approximately independently of initial GC mass and inverselycorrelated with initial cluster radius. Scaling the results to the Milky Way GC population, we find that ∼75% of the S–BH binariesformed in GCs are ejected from their host GC, all in the early phases of evolution (.1 Gyr); these are expected to no longer be closeto streams. The ∼25% of S–BH binaries retained until dissolution are expected to form part of streams, such that for an initial massof the progenitor of ED-2 of a few 104 M , we expect ∼2−3 S–BH to end up in the stream. GC models with metallicities similar toGaia BH3 (.1% solar) include S–BH binaries with similar BH masses (&30 M ), orbital periods, and eccentricities.Conclusion. We predict that the Galactic halo contains of order 105 S–BH binaries that formed dynamically in GCs, a fraction ofwhich may readily be detected in Gaia DR4. The detection of these sources provides valuable tests of BH dynamics in clusters andtheir contribution to gravitational wave sources |
Note: | Reproducció del document publicat a: https://doi.org/10.1051/0004-6361/202450460 |
It is part of: | Astronomy & Astrophysics, 2024 |
URI: | https://hdl.handle.net/2445/220948 |
Related resource: | https://doi.org/10.1051/0004-6361/202450460 |
ISSN: | 0004-6361 |
Appears in Collections: | Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB)) |
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