Massive black hole binaries (MBHBs) are expected to form at the centre of merging galaxies during the hierarchical assembly of the cosmic structure, and are expected to be the loudest sources of gravitational waves (GWs) in the low-frequency domain. However, because of the dearth of energy exchanges with background stars and gas, many of these MBHBs may stall at separations that are too large for GW emission to drive them to coalescence in less than a Hubble time. Triple MBH systems are then bound to form after a further galaxy merger, triggering a complex and rich dynamics that can eventually lead to MBH coalescence. Here, we report on the results of a large set of numerical simulations, where MBH triplets are set in spherical stellar potentials and MBH dynamics is followed through 2.5 post-Newtonian orders in the equations of motion. From our full suite of simulated systems, we find that a fraction (similar or equal to 20-30 per cent) of the MBH binaries that would otherwise stall is led to coalesce within a Hubble time. The corresponding coalescence time-scale peaks around 300 Myr, while the eccentricity close to the plunge, albeit small, is non-negligible (less than or similar to 0.1). We construct and discuss marginalized probability distributions of the main parameters involved and, in a companion paper of the series, we will use the results presented here to forecast the contribution of MBH triplets to the GW signal in the nHz regime probed by Pulsar Timing Array experiments

Bonetti, M., Haardt, F., Sesana, A., Barausse, E. (2018). Post-Newtonian evolution of massive black hole triplets in galactic nuclei – II. Survey of the parameter space. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 477(3), 3910-3926 [10.1093/mnras/sty896].

Post-Newtonian evolution of massive black hole triplets in galactic nuclei – II. Survey of the parameter space

Bonetti, Matteo
Primo
;
Sesana, Alberto;
2018

Abstract

Massive black hole binaries (MBHBs) are expected to form at the centre of merging galaxies during the hierarchical assembly of the cosmic structure, and are expected to be the loudest sources of gravitational waves (GWs) in the low-frequency domain. However, because of the dearth of energy exchanges with background stars and gas, many of these MBHBs may stall at separations that are too large for GW emission to drive them to coalescence in less than a Hubble time. Triple MBH systems are then bound to form after a further galaxy merger, triggering a complex and rich dynamics that can eventually lead to MBH coalescence. Here, we report on the results of a large set of numerical simulations, where MBH triplets are set in spherical stellar potentials and MBH dynamics is followed through 2.5 post-Newtonian orders in the equations of motion. From our full suite of simulated systems, we find that a fraction (similar or equal to 20-30 per cent) of the MBH binaries that would otherwise stall is led to coalesce within a Hubble time. The corresponding coalescence time-scale peaks around 300 Myr, while the eccentricity close to the plunge, albeit small, is non-negligible (less than or similar to 0.1). We construct and discuss marginalized probability distributions of the main parameters involved and, in a companion paper of the series, we will use the results presented here to forecast the contribution of MBH triplets to the GW signal in the nHz regime probed by Pulsar Timing Array experiments
Articolo in rivista - Articolo scientifico
Black hole physics; Galaxies: Kinematics and dynamics; Gravitation; Gravitational waves; Methods: Numerical;
English
2018
477
3
3910
3926
none
Bonetti, M., Haardt, F., Sesana, A., Barausse, E. (2018). Post-Newtonian evolution of massive black hole triplets in galactic nuclei – II. Survey of the parameter space. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 477(3), 3910-3926 [10.1093/mnras/sty896].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/253887
Citazioni
  • Scopus 50
  • ???jsp.display-item.citation.isi??? 46
Social impact