Title：A Multi-Messenger Mass Determination Method for Neutron Stars

Speaker：Jane Sinan Long (University College London)

Time: 3:00 pm Dec. 12th (Friday)

Location:  Small Conference Room, 3rd floor

Abstract：

Neutron stars (NSs) serve as natural laboratories for probing quantum phenomena under extreme gravitational conditions. Their maximum masses—marking the threshold before collapse into a black hole—provide essential tests of the underlying equation of state. In this talk, we present a novel multi-messenger mass determination method to accurately measure the masses of heavy neutron stars in ultra-compact binary systems. By combining the binary mass function obtained from optical observations and a gravitational wave (GW) mass function, that we introduce, derived from GW observations, we demonstrate how we can set improved constraints on the neutron star mass and break the degeneracy in the mass and viewing inclination determination.  We further explore the universal relation between the GW mass function’s error and the gravitational wave signal-to-noise ratio (SNR), and propose a straightforward framework for estimating the capability of LISA’s gravitational wave observations in refining mass determinations. Our results indicate that for neutron star–white dwarf binaries within our Galaxy, the neutron star mass can be constrained to within an accuracy of ±0.2 M⊙.

CV：

Jane Sinan Long is a second-year PhD student at University College London, supported by Research Excellence Scholarship. She earned her Master’s degree from National Tsing Hua University in 2023. Her research background spans the analysis of real observational data across X-ray, gamma-ray, and optical wavelengths, and she has served as Principal Investigator on two successful Liverpool Telescope proposals. Currently, she focuses on theoretical modeling of multi-messenger signals from neutron star mergers, including gravitational waves and neutrinos, and is developing general relativistic radiative transfer codes for neutrinos. In today’s talk, she will introduce a new multi-messenger method to determining the masses of massive neutron stars in pulsar binaries—systems that are potential gravitational wave sources detectable by LISA. This work was published in APJ earlier this year.