Data di Pubblicazione:
2015
Citazione:
Spin alignment and differential accretion in merging black hole binaries / D. Gerosa, B. Veronesi, G. Lodato, G. Rosotti. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 451:4(2015), pp. 3941-3954.
Abstract:
Interactions between a supermassive black hole binary and the surrounding accretion disc can
both assist the binary inspiral and align the black hole spins to the disc angular momentum.
While binary migration is due to angular-momentum transfer within the circumbinary disc,
the spin-alignment process is driven by the mass accreting on to each black hole. Mass transfer
between different disc components thus couples the inspiral and the alignment process together.
Mass is expected to leak through the cavity cleared by the binary, and preferentially accretes on
to the lighter (secondary) black hole which orbits closer to the disc edge. Low accretion rate on
to the heavier (primary) black hole slows the alignment process down. We revisit the problem
and develop a semi-analytical model to describe the coupling between gas-driven inspiral and
spin alignment, finding that binaries with mass ratio q 0.2 approach the gravitational-wave
driven inspiral in differential misalignment: light secondaries prevent primaries from aligning.
Binary black holes with misaligned primaries are ideal candidates for precession effects in the
strong-gravity regime and may suffer from moderately large (∼1500 km s−1) recoil velocities.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
accretion; accretion discs; black hole physics; galaxies: evolution; galaxies:nuclei
Elenco autori:
D. Gerosa, B. Veronesi, G. Lodato, G. Rosotti
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