Realistic Detection and Early Warning of Binary Neutron Stars with Decihertz Gravitational-wave Observatories

TL;DR

This paper evaluates the capabilities of decihertz gravitational-wave observatories, especially B-DECIGO, in detecting binary neutron stars, providing early warnings, and comparing their performance with ground-based detectors under realistic conditions.

Contribution

It offers a comprehensive analysis of detection rates, early warning potential, and localization accuracy of decihertz detectors, including strategies for noise mitigation and comparison with other observatories.

Findings

Decihertz detectors can provide early warnings decades before merger.

Localization accuracy can reach as precise as 10^{-2} deg^2 for certain sources.

Detection rates are affected by confusion noise, but can be improved with noise subtraction.

Abstract

We investigated the detection rates and early warning parameters of binary neutron star (BNS) populations with decihertz gravitational-wave observatories in a realistic detecting strategy. Assuming 4 years' operation of B-DECIGO, we based on parameter precision to classify the detectable BNSs into three categories: (a) sources that merge within 1 year, which could be localized with an uncertainty of $\Delta\Omega \sim 10^{0}$ deg$^2$; (b) sources that merge in 1-4 years, which take up three quarters of the total events and yield the most precise angular resolution with $\Delta \Omega\sim 10^{-2}$ deg$^2$ and time-of-merger accuracy with $\Delta t_c\sim 10^{-1}$ s; and (c) sources that do not merge during the 4-yr mission window, which enable possible early warnings, with $\Delta \Omega\sim 10^{-1}$ deg$^2$ and $\Delta t_c\sim 10^{0}$ s. Furthermore, we compared the pros and cons of B-DECIGO with the third-generation ground-based detectors, and explored the prospects of detections using 3 other decihertz observatories and 4 BNS population models. In realistic observing scenarios, we found that decihertz detectors could even provide early-warning alerts to a source decades before its merger while their localizations are still as accurate as ground-based facilities. Finally we found a decrease of events when considering the confusion noise, but this could be partially solved by a proper noise subtraction.