No tension between assembly models of super massive black hole binaries and pulsar observations
Hannah Middleton, Siyuan Chen, Walter Del Pozzo, Alberto Sesana, Alberto Vecchio
Nature Communications | NATURE PUBLISHING GROUP | Published : 2018
Pulsar timing arrays are presently the only means to search for the gravitational wave stochastic background from super massive black hole binary populations, considered to be within the grasp of current or near-future observations. The stringent upper limit from the Parkes Pulsar Timing Array has been interpreted as excluding (>90% confidence) the current paradigm of binary assembly through galaxy mergers and hardening via stellar interaction, suggesting evolution is accelerated or stalled. Using Bayesian hierarchical modelling we consider implications of this upper limit for a range of astrophysical scenarios, without invoking stalling, nor more exotic physical processes. All scenarios are..View full abstract
Awarded by Science and Technology Facilities Council
H.M. and A.V. acknowledge the support by the Science and Technology Facilities Council (STFC). S.C. acknowledges the support of the University of Birmingham via the AE Hills scholarship. A.S. is supported by a URF of the Royal Society.