(An)isotropy measurement with gravitational wave observations
Abstract
We constrain the distribution of merging compact binaries across the celestial sphere using the GWTC3 catalog from the LIGOVirgoKAGRA Collaborations' (LVK) third observing run. With 63 confident detections from O3, we constrain the relative variability (standard deviation) of the rate density across the sky to be ≲16 % at 90% confidence assuming the logarithm of the rate density is described by a Gaussian random field with correlation length ≥1 0 ° . This tightens to ≲3.5 % when the correlation length is ≥2 0 ° . While the new data provides the tightest constraints on anisotropies available to date, we do not find overwhelming evidence in favor of isotropy, either. A simple counting experiment favors an isotropic distribution by a factor of B_{ani}^{iso}=3.7 , which is nonetheless an improvement of more than a factor of two compared to analogous analyses based on only the LVK's first and second observing runs.
 Publication:

Physical Review D
 Pub Date:
 February 2023
 DOI:
 10.1103/PhysRevD.107.043016
 arXiv:
 arXiv:2207.05792
 Bibcode:
 2023PhRvD.107d3016E
 Keywords:

 Astrophysics  High Energy Astrophysical Phenomena
 EPrint:
 main text: 12 pages, 6 figures, 2 tables