Pre-merger localization of eccentric compact binary coalescences with second-generation gravitational-wave detector networks

Abstract

We study the possibility of pre-merger localization of eccentric compact binary coalescences by second-generation gravitational-wave detector networks. Gravitational waves from eccentric binaries can be regarded as a sequence of pulses, which are composed of various higher harmonic modes than ones with twice the orbital frequency. The higher harmonic modes from a very early inspiral phase will not only contribute to the signal-to-noise ratio, but also allow us to localize the gravitational-wave source before the merger sets in. This is due to the fact that high-frequency gravitational waves are essential for the source localization via triangulation by ground-based detector networks. We found that the single-detector signal-to-noise ratio exceeds 5 at 10 min before the merger for a 1.4--1.4 $M_\odot$ eccentric binary neutron stars at 100 Mpc in optimal cases, and it can be localized up to 10 deg$^2$ at half a minute before the merger by a four-detector network. We will even be able to achieve $\sim$ 10 deg$^2$ at 10 min before the merger for a face-on eccentric compact binary by a five-detector network.