Testing the validity of the phenomenological gravitational waveform models for nonspinning binary black hole searches at low masses

Abstract

The phenomenological gravitational waveform models, which we refer to as PhenomA, PhenomB and PhenomC, generate full inspiral-merger-ringdown waveforms of coalescing binary back holes (BBHs). These models are defined in the Fourier domain, thus can be used for fast matched filtering in the gravitational wave search. PhenomA has been developed for nonspinning BBH waveforms, while PhenomB and PhenomC were designed to model the waveforms of BBH systems with nonprecessing (aligned) spins, but can also be used for nonspinning systems. In this work, we study the validity of the phenomenological models for nonspinning BBH searches at low masses, m 1,2 ≥ 4M and m 1 + m 2 ≡ M ≤ 30M , with Advanced LIGO. As our complete signal waveform model, we adopt EOBNRv2 that is a time-domain inspiral-merger-ringdown waveform model. To investigate the search efficiency of the phenomenological template models, we calculate fitting factors by exploring overlap surfaces. We find that only PhenomC is valid to obtain the fitting factors better than 0.97 in the mass range of M < 15M . Above 15M , PhenomA is most efficient in symmetric mass region, PhenomB is most efficient in highly asymmetric mass region, and PhenomC is most efficient in the intermediate region. Specifically, we propose an effective phenomenological template family that can be constructed by employing the phenomenological models in four subregions individually. We find that fitting factors of the effective templates are better than 0.97 in our entire mass region and mostly greater than 0.99.

Gravitational wave searches for aligned-spin binary neutron stars using nonspinning templates

“…As the efficiency of a template waveform model for the search is evaluated by the fitting factor, its validity for the parameter estimation can be examined by the bias [30][31][32]. We determine the fitting factor and the bias in the following way [20,32,33]. First, we repeat a grid search around λ 0 until we find the crude location of λ rec in the overlap surface.…”

“…We determine the fitting factor and the bias in the following way [20,32,33]. First, we repeat a grid search around λ 0 until we find the crude location of λ rec in the overlap surface.…”

Accuracy in measuring the neutron star mass in the gravitational wave parameter estimation for black hole-neutron star binaries

“…However, for more massive systems, full inspiral-merger-ringdown waveform models should be used not to lose the merger-ringdown portions. For this purpose, various models have been developed over the past years, and the phenomenological models have been commonly used [34][35][36][37][38][39][40] (for a brief description of these models, see [41]). Since the phenomenological models are constructed as analytic functions in the frequency-domain, those are also applicable to the FM method.…”

Systematic bias due to nonspinning template waveforms in the gravitational wave parameter estimation for aligned-spin binary black holes

“…where A eff and Ψ eff are the effective amplitude and the effective phase, and those are modeled separately and parameterized by using the mass and the spin parameters [39].…”