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

Abstract

So far, in total 15 double neutron star systems (DNSs) with a reliable measurement of the total gravitational mass ($M_{\mathrm{T}}$) have been detected in the Galaxy. In this work we study the distribution of $M_{\mathrm{T}}$. The data prefer the double Gaussian distribution over a single Gaussian distribution and the low and high mass populations center at $M_{\mathrm{T}}\sim 2.58M_{\odot }$ and $\sim 2.72M_{\odot }$, respectively. The progenitor stars of GW170817 have a $M_{\mathrm{T}}=2.74_{-0.01}^{+0.04}{M}_{\odot }$, falling into the high mass population. With a local neutron star merger rate of $\sim 10^3\mathrm{Gp}{\mathrm{c}}^{-3}\mathrm{y}{\mathrm{r}}^{-1}$, supposing the $M_{\mathrm{T}}$ 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 $M_{\mathrm{T}}\lesssim 2.6M_{\odot }$ 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.

6 pages,1 table and 3 figures

References in corpus (2)

• Using gravitational-wave observations and quasi-universal relations to constrain the maximum mass of neutron stars
• GW170817 and the prospect of forming supramassive remnants in neutron star mergers

Cited by in corpus (2)

• Black holes in the low mass gap: Implications for gravitational wave observations
• Galactic Double Neutron Star total masses and Gaussian mixture model selection