The NANOGrav 11yr Data Set: Limits on Supermassive Black Hole Binaries in Galaxies within 500Mpc
Abstract
Supermassive black hole binaries (SMBHBs) should form frequently in galactic nuclei as a result of galaxy mergers. At sub-parsec separations, binaries become strong sources of low-frequency gravitational waves (GWs), targeted by Pulsar Timing Arrays (PTAs). We used recent upper limits on continuous GWs from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) 11yr dataset to place constraints on putative SMBHBs in nearby massive galaxies. We compiled a comprehensive catalog of ~44,000 galaxies in the local universe (up to redshift ~0.05) and populated them with hypothetical binaries, assuming that the total mass of the binary is equal to the SMBH mass derived from global scaling relations. Assuming circular equal-mass binaries emitting at NANOGrav's most sensitive frequency of 8nHz, we found that 216 galaxies are within NANOGrav's sensitivity volume. We ranked the potential SMBHBs based on GW detectability by calculating the total signal-to-noise ratio (S/N) such binaries would induce within the NANOGrav array. We placed constraints on the chirp mass and mass ratio of the 216 hypothetical binaries. For 19 galaxies, only very unequal-mass binaries are allowed, with the mass of the secondary less than 10 percent that of the primary, roughly comparable to constraints on a SMBHB in the Milky Way. Additionally, we were able to exclude binaries delivered by major mergers (mass ratio of at least 1/4) for several of these galaxies. We also derived the first limit on the density of binaries delivered by major mergers purely based on GW data.
Keywords
Cite
@article{arxiv.2101.02716,
title = {The NANOGrav 11yr Data Set: Limits on Supermassive Black Hole Binaries in Galaxies within 500Mpc},
author = {Zaven Arzoumanian and Paul T. Baker and Adam Brazier and Paul R. Brook and Sarah Burke-Spolaor and Bence Becsy and Maria Charisi and Shami Chatterjee and James M. Cordes and Neil J. Cornish and Fronefield Crawford and H. Thankful Cromartie and Megan E. DeCesar and Paul B. Demorest and Timothy Dolch and Rodney D. Elliott and Justin A. Ellis and Elizabeth C. Ferrara and Emmanuel Fonseca and Nathan Garver-Daniels and Peter A. Gentile and Deborah C. Good and Jeffrey S. Hazboun and Kristina Islo and Ross J. Jennings and Megan L. Jones and Andrew R. Kaiser and David L. Kaplan and Luke Z. Kelley and Joey Shapiro Key and Michael T. Lam and T. Joseph W. Lazio and Jing Luo and Ryan S. Lynch and Chung-Pei Ma and Dustin R. Madison and Maura A. McLaughlin and Chiara M. F. Mingarelli and Cherry Ng and David J. Nice and Timothy T. Pennucci and Nihan S. Pol and Scott M. Ransom and Paul S. Ray and Brent J. Shapiro-Albert and Xavier Siemens and Joseph Simon and Renee Spiewak and Ingrid H. Stairs and Daniel R. Stinebring and Kevin Stovall and Joseph K. Swiggum and Stephen R. Taylor and Michele Vallisneri and Sarah J. Vigeland and Caitlin A. Witt and The NANOGrav Collaboration},
journal= {arXiv preprint arXiv:2101.02716},
year = {2021}
}
Comments
Submitted to ApJ. Send comments to Maria Charisi ([email protected])