Parametrized tests of postNewtonian theory using principal component analysis
Abstract
Searching for departures from general relativity (GR) in more than one postNewtonian (PN) phasing coefficients, called a \emph{multiparameter test}, is known to be ineffective given the sensitivity of the present generation of gravitationalwave (GW) detectors. Strong degeneracies in the parameter space make the outcome of the test uninformative. We argue that Principal Component Analysis (PCA) can remedy this problem by constructing certain linear combinations of the original PN parameters that are better constrained by gravitationalwave observations. By analyzing binary black hole events detected during the first and second observing runs (O1 and O2) of LIGO/Virgo, we show that the two dominant principal components can capture the essence of a multiparameter test. Combining five binary black hole mergers during O1/O2, we find that the dominant linear combination of the PN coefficients obtained from PCA is consistent with GR within the 0.38 standard deviation of the posterior distribution. Furthermore, using a set of simulated \emph{nonGR} signals in the threedetector LIGOVirgo network with designed sensitivities, we find that the method is capable of excluding GR with high confidence as well as recovering the injected values of the nonGR parameters with good precision.
 Publication:

arXiv eprints
 Pub Date:
 October 2021
 arXiv:
 arXiv:2110.10147
 Bibcode:
 2021arXiv211010147S
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics  High Energy Astrophysical Phenomena
 EPrint:
 10 pages, 4 figures, 2 tables