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Title: Multimessenger time-domain signatures of supermassive black hole binaries
ABSTRACT

Supermassive black hole binaries (SMBHBs) are a natural outcome of galaxy mergers and should form frequently in galactic nuclei. Sub-parsec binaries can be identified from their bright electromagnetic emission, e.g. Active Galactic Nuclei (AGNs) with Doppler shifted broad emission lines or AGN with periodic variability, as well as from the emission of strong gravitational radiation. The most massive binaries (with total mass >108M⊙) emit in the nanohertz band and are targeted by Pulsar Timing Arrays (PTAs). Here we examine the synergy between electromagnetic and gravitational wave signatures of SMBHBs. We connect both signals to the orbital dynamics of the binary and examine the common link between them, laying the foundation for joint multimessenger observations. We find that periodic variability arising from relativistic Doppler boost is the most promising electromagnetic signature to connect with GWs. We delineate the parameter space (binary total mass/chirp mass versus binary period/GW frequency) for which joint observations are feasible. Currently multimessenger detections are possible only for the most massive and nearby galaxies, limited by the sensitivity of PTAs. However, we demonstrate that as PTAs collect more data in the upcoming years, the overlapping parameter space is expected to expand significantly.

 
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Award ID(s):
2020265 2009539 1945546 2108668 1908042 2007993
NSF-PAR ID:
10362035
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Oxford University Press
Date Published:
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
510
Issue:
4
ISSN:
0035-8711
Page Range / eLocation ID:
p. 5929-5944
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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