Total gravitational mass of the Galactic Double Neutron Star systems: evidence for a bimodal distribution

2018/04/09 by Huang, Yong-Jia, Jiang, Jin-Liang, Li, Xiang +3
#FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Astrophysical Phenomena (astro-ph.HE)

paper · doi:10.48550/arxiv.1804.03101

Abstract

So far, in total 15 double neutron star systems (DNSs) with a reliable measurement of the total gravitational mass (M_{\rm T}) have been detected in the Galaxy. In this work we study the distribution of M_{\rm T}. The data prefer the double Gaussian distribution over a single Gaussian distribution and the low and high mass populations center at M_{\rm T}∼ 2.58M_\odot and ∼ 2.72M_\odot, respectively. The progenitor stars of GW170817 have a M_{\rm T}=2.74^+0.04_-0.01M_\odot, falling into the high mass population. With a local neutron star merger rate of ∼ 10³~\rm Gpc^-3~yr^-1, supposing the M_{\rm T} of those merging neutron stars also follow the double Gaussian distribution, the upcoming runs of the advanced LIGO/Virgo will soon detect some events with a M_{\rm T}\lesssim 2.6M_\odot that can effectively probe the equation of state of the neutron stars and the distribution function is expected to be reliably reconstructed in the next decade.

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