Abstract
After the discovery of gravitational waves from binary black holes (BBHs) and binary neutron stars (BNSs) with the LIGO and Virgo detectors, neutron-star black holes (NSBHs) are the natural next class of binary systems to be observed. In this work, we develop a waveform model for aligned-spin NSBHs combining a BBH baseline waveform (available in the effective-one-body approach) with a phenomenological description of tidal effects (extracted from numerical-relativity simulations) and correcting the amplitude during the late inspiral, merger and ringdown to account for the NS tidal disruption. In particular, we calibrate the amplitude corrections using NSBH waveforms obtained with the numerical-relativity spectral Einstein code (spec) and the sacra code. The model was calibrated using simulations with NS masses in the range $1.2--1.4\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$, tidal deformabilities up to 4200 (for a $1.2\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$ NS), and dimensionless BH spin magnitude up to 0.9. Based on the simulations used and on checking that sensible waveforms are produced, we recommend our model to be employed with a NS mass in the range $1--3\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$, tidal deformability 0--5000, and (dimensionless) BH spin magnitude up to 0.9. We also validate our model against two new, highly accurate NSBH waveforms with BH spin 0.9 and mass ratios 3 and 4, characterized by tidal disruption, produced with SpEC, and find very good agreement. Furthermore, we compute the unfaithfulness between waveforms from NSBH, BBH, and BNS systems, finding that it will be challenging for the Advanced LIGO-Virgo detector network at design sensitivity to distinguish different source classes. We perform a Bayesian parameter-estimation analysis on a synthetic numerical-relativity signal in zero noise to study parameter biases. Finally, we reanalyze GW170817, with the hypothesis that it is a NSBH. We do not find evidence to distinguish the BNS and NSBH hypotheses; however, the posterior for the mass ratio is shifted to less equal masses under the NSBH hypothesis.
Highlights
In their first two observing runs (O1 and O2), Advanced LIGO [1] and Advanced Virgo [2] have observed gravitational waves (GWs) from ten binary black holes (BBHs) and one binary neutron star (BNS), GW170817 [3]
GW data alone do not exclude the possibility that GW170817 is a Neutron-star black holes (NSBHs) [17,18,19], and it has been suggested that GW190425 could be a NSBH [20,21]
We show the recovery of the signal-to-noise ratios (SNRs) 1⁄4 75 injection, for which the SEOBNR_NSBH recovery is marginally consistent with the true parameters, in the right two panels of Fig. 8
Summary
In their first two observing runs (O1 and O2), Advanced LIGO [1] and Advanced Virgo [2] have observed gravitational waves (GWs) from ten binary black holes (BBHs) and one binary neutron star (BNS), GW170817 [3]. References [58,59] developed a flexible technique that starts from a point-mass BBH baseline waveform and applies tidal-phase modifications by fitting a Pade-resummed post-Newtonian (PN)-based ansatz to the phasing extracted from numerical-relativity (NR) simulations (we refer to this as the NRTidal approach). These corrections have been applied to BBH baselines produced within the EOBNR framework [60] and within the inspiral-merger-ringdown phenomenological (IMRPhenom) approach [61,62]. An aligned-spin NSBH waveform model was developed in Refs.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.