Parameter estimation on gravitational waves from neutron-star binaries with spinning components

TL;DR

This study assesses how accurately gravitational-wave signals from neutron-star binaries can be characterized using Advanced LIGO data, focusing on mass, spin, and sky localization, with implications for electromagnetic follow-up.

Contribution

It provides a comprehensive analysis of parameter estimation accuracy for neutron-star binaries with low spins using the full LIGO pipeline, highlighting the impact of prior assumptions.

Findings

Mass estimates have ~16% fractional uncertainty.

Spin constraints are weak, with median 90% upper limit ~0.7.

Sky position and luminosity distance are unaffected by spin assumptions.

Abstract

Inspiraling binary neutron stars are expected to be one of the most significant sources of gravitational-wave signals for the new generation of advanced ground-based detectors. We investigate how well we could hope to measure properties of these binaries using the Advanced LIGO detectors, which began operation in September 2015. We study an astrophysically motivated population of sources (binary components with masses $1.2~\mathrm{M}_\odot$--$1.6~\mathrm{M}_\odot$ and spins of less than $0.05$) using the full LIGO analysis pipeline. While this simulated population covers the observed range of potential binary neutron-star sources, we do not exclude the possibility of sources with parameters outside these ranges; given the existing uncertainty in distributions of mass and spin, it is critical that analyses account for the full range of possible mass and spin configurations. We find that conservative prior assumptions on neutron-star mass and spin lead to average fractional uncertainties in component masses of $\sim 16\%$, with little constraint on spins (the median $90\%$ upper limit on the spin of the more massive component is $\sim 0.7$). Stronger prior constraints on neutron-star spins can further constrain mass estimates, but only marginally. However, we find that the sky position and luminosity distance for these sources are not influenced by the inclusion of spin; therefore, if LIGO detects a low-spin population of BNS sources, less computationally expensive results calculated neglecting spin will be sufficient for guiding electromagnetic follow-up.