TY - JOUR

T1 - Testing gravitational waveform models using angular momentum

AU - Khera, Neev

AU - Ashtekar, Abhay

AU - Krishnan, Badri

N1 - Funding Information: This work was supported by the NSF Grant No. PHY-1806356, the Eberly Chair funds of Penn State, and the Mebus Fellowship to N. K. Computations for this research were performed on the Roar supercomputer of the Pennsylvania State University’s Institute for Computational and Data Sciences. We thank Frank Ohme and Angela Borchers Pascual for discussions and comments; Eric Thrane for the suggestion of adding memory to the NR waveforms; and the referee for suggesting that we add the plots that now appear in Appendix . We also acknowledge the use of the lalsimulation , p y cbc , scri , and spinsfast software packages in this paper.

PY - 2021/12/27

Y1 - 2021/12/27

N2 - The anticipated enhancements in detector sensitivity and the corresponding increase in the number of gravitational wave detections will make it possible to estimate parameters of compact binaries with greater accuracy assuming general relativity(GR), and also to carry out sharper tests of GR itself. Crucial to these procedures are accurate gravitational waveform models. The systematic errors of the models must stay below statistical errors to prevent biases in parameter estimation and to carry out meaningful tests of GR. Comparisons of the models against numerical relativity (NR) waveforms provide an excellent measure of systematic errors. A complementary approach is to use balance laws provided by Einstein's equations to measure faithfulness of a candidate waveform against exact GR. Each balance law focuses on a physical observable and measures the accuracy of the candidate waveform vis a vis that observable. Therefore, this analysis can provide new physical insights into sources of errors. In this paper we focus on the angular momentum balance law, using post-Newtonian theory to calculate the initial angular momentum, surrogate fits to obtain the remnant spin and waveforms from models to calculate the flux. The consistency check provided by the angular momentum balance law brings out the marked improvement in the passage from \texttt{IMRPhenomPv2} to \texttt{IMRPhenomXPHM} and from \texttt{SEOBNRv3} to \texttt{SEOBNRv4PHM} and shows that the most recent versions agree quite well with exact GR. For precessing systems, on the other hand, we find that there is room for further improvement, especially for the Phenom models.

AB - The anticipated enhancements in detector sensitivity and the corresponding increase in the number of gravitational wave detections will make it possible to estimate parameters of compact binaries with greater accuracy assuming general relativity(GR), and also to carry out sharper tests of GR itself. Crucial to these procedures are accurate gravitational waveform models. The systematic errors of the models must stay below statistical errors to prevent biases in parameter estimation and to carry out meaningful tests of GR. Comparisons of the models against numerical relativity (NR) waveforms provide an excellent measure of systematic errors. A complementary approach is to use balance laws provided by Einstein's equations to measure faithfulness of a candidate waveform against exact GR. Each balance law focuses on a physical observable and measures the accuracy of the candidate waveform vis a vis that observable. Therefore, this analysis can provide new physical insights into sources of errors. In this paper we focus on the angular momentum balance law, using post-Newtonian theory to calculate the initial angular momentum, surrogate fits to obtain the remnant spin and waveforms from models to calculate the flux. The consistency check provided by the angular momentum balance law brings out the marked improvement in the passage from \texttt{IMRPhenomPv2} to \texttt{IMRPhenomXPHM} and from \texttt{SEOBNRv3} to \texttt{SEOBNRv4PHM} and shows that the most recent versions agree quite well with exact GR. For precessing systems, on the other hand, we find that there is room for further improvement, especially for the Phenom models.

KW - gr-qc

UR - http://www.scopus.com/inward/record.url?scp=85122365889&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.104.124071

DO - 10.1103/PhysRevD.104.124071

M3 - Article

VL - 104

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 12

M1 - 124071

ER -