TY - JOUR
T1 - Triplets of supermassive black holes: Astrophysics, gravitational waves and detection
AU - Amaro-Seoane, Pau
AU - Sesana, Alberto
AU - Hoffman, Loren
AU - Benacquista, Matthew
AU - Eichhorn, Christoph
AU - Makino, Junichiro
AU - Spurzem, Rainer
PY - 2010/1/1
Y1 - 2010/1/1
N2 - Supermassive black holes (SMBHs) found in the centres of many galaxies are understood to play a fundamental, active role in the cosmological structure formation process. In hierarchical formation scenarios, SMBHs are expected to form binaries following the merger of their host galaxies. If these binaries do not coalesce before the merger with a third galaxy, the formation of a black hole triple system is possible. Numerical simulations of the dynamics of triples within galaxy cores exhibit phases of very high eccentricity (as high as e∼ 0.99). During these phases, intense bursts of gravitational radiation can be emitted at orbital periapsis, which produces a gravitational wave signal at frequencies substantially higher than the orbital frequency. The likelihood of detection of these bursts with pulsar timing and the Laser Interferometer Space Antenna (LISA) is estimated using several population models of SMBHs with masses >rsim 107 M⊙. Assuming that 10 per cent or more of binaries are in triple systems, we find that up to a few dozen of these bursts will produce residuals >1 ns, within the sensitivity range of forthcoming pulsar timing arrays. However, most of such bursts will be washed out in the underlying confusion noise produced by all the other 'standard' SMBH binaries emitting in the same frequency window. A detailed data analysis study would be required to assess resolvability of such sources. Implementing a basic resolvability criterion, we find that the chance of catching a resolvable burst at a 1 ns precision level is 2-50 per cent, depending on the adopted SMBH evolution model. On the other hand, the probability of detecting bursts produced by massive binaries (masses ≳107 M⊙) with LISA is negligible. © 2010 The Authors. Journal compilation © 2010 RAS.
AB - Supermassive black holes (SMBHs) found in the centres of many galaxies are understood to play a fundamental, active role in the cosmological structure formation process. In hierarchical formation scenarios, SMBHs are expected to form binaries following the merger of their host galaxies. If these binaries do not coalesce before the merger with a third galaxy, the formation of a black hole triple system is possible. Numerical simulations of the dynamics of triples within galaxy cores exhibit phases of very high eccentricity (as high as e∼ 0.99). During these phases, intense bursts of gravitational radiation can be emitted at orbital periapsis, which produces a gravitational wave signal at frequencies substantially higher than the orbital frequency. The likelihood of detection of these bursts with pulsar timing and the Laser Interferometer Space Antenna (LISA) is estimated using several population models of SMBHs with masses >rsim 107 M⊙. Assuming that 10 per cent or more of binaries are in triple systems, we find that up to a few dozen of these bursts will produce residuals >1 ns, within the sensitivity range of forthcoming pulsar timing arrays. However, most of such bursts will be washed out in the underlying confusion noise produced by all the other 'standard' SMBH binaries emitting in the same frequency window. A detailed data analysis study would be required to assess resolvability of such sources. Implementing a basic resolvability criterion, we find that the chance of catching a resolvable burst at a 1 ns precision level is 2-50 per cent, depending on the adopted SMBH evolution model. On the other hand, the probability of detecting bursts produced by massive binaries (masses ≳107 M⊙) with LISA is negligible. © 2010 The Authors. Journal compilation © 2010 RAS.
KW - Cosmology: theory
KW - Gravitational waves
KW - Pulsars: general
U2 - 10.1111/j.1365-2966.2009.16104.x
DO - 10.1111/j.1365-2966.2009.16104.x
M3 - Article
VL - 402
SP - 2308
EP - 2320
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 4
ER -