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Title: Inferring M BH – M bulge Evolution from the Gravitational-wave Background
Abstract We test the impact of an evolving supermassive black hole mass scaling relation (MBH–Mbulge) on the predictions for the gravitational-wave background (GWB). The observed GWB amplitude is 2–3 times higher than predicted by astrophysically informed models, which suggests the need to revise the assumptions in those models. We compare a semi-analytic model’s ability to reproduce the observed GWB spectrum with a static versus evolving-amplitudeMBH–Mbulgerelation. We additionally consider the influence of the choice of galaxy stellar mass function (GSMF) on the modeled GWB spectra. Our models are able to reproduce the GWB amplitude with either a large number density of massive galaxies or a positively evolvingMBH–Mbulgeamplitude (i.e., theMBH/Mbulgeratio was higher in the past). If we assume that theMBH–Mbulgeamplitude does not evolve, our models require a GSMF that implies an undetected population of massive galaxies (M⋆≥ 1011M⊙atz> 1). When theMBH–Mbulgeamplitude is allowed to evolve, we can model the GWB spectrum with all fiducial values and anMBH–Mbulgeamplitude that evolves asα(z) =α0(1 +z)1.04±0.5.  more » « less
Award ID(s):
2307719 2146016
PAR ID:
10661524
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publisher / Repository:
IOP
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
997
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
188
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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