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F1C59E7D-0E2F-42DE-8CEF-38159109FF1D

An Isotropy Measurement with Gravitational Wave Observations

Reed Essick, Will M. Farr, Maya Fishbach, Daniel E. Holz, Erik Katsavounidis
arXiv:2207.05792

Submitted on 12 July 2022

Abstract

We constrain the distribution of merging compact binaries across the celestial sphere using the GWTC-3 catalog from the LIGO-Virgo-KAGRA 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 10. This tightens to 3.5% when the correlation length is 20. While the new O3 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 Baniiso=3.7, which is nonetheless an improvement of more than a factor of two compared to analogous analyses based on only the first and second observing runs of the LVK.

Preprint

Comment: main text: 12 pages, 6 figures, 2 tables

Subject: Astrophysics - High Energy Astrophysical Phenomena

URL: https://arxiv.org/abs/2207.05792