Combining new gravitational waveforms derived by long-term (14 to 16 orbit) numerical-relativity simulations with waveforms by an effective-one-body (EOB) formalism for coalescing binary neutron stars, we construct hybrid waveforms and estimate the measurability for the dimensionless tidal deformability of the neutron stars, $\mathrm{\Lambda }$, by advanced gravitational-wave detectors. We focus on the equal-mass case with the total mass $2.7M_{\odot }$. We find that for an event at a hypothetical effective distance of $D_{\mathrm{eff}}=200\mathrm{Mpc}$, the distinguishable difference in the dimensionless tidal deformability will be $\approx 100$, 400, and 800 at $1\sigma$, $2\sigma$, and $3\sigma$ levels, respectively, for Advanced LIGO. If the true equation of state is stiff and the typical neutron-star radius is $R\gtrsim 13\mathrm{km}$, our analysis suggests that the radius will be constrained within $\approx 1\mathrm{km}$ at $2\sigma$ level for an event at $D_{\mathrm{eff}}=200\mathrm{Mpc}$. On the other hand, if the true equation of state is soft and the typical neutron-star radius is $R\lesssim 12\mathrm{km}$, it will be difficult to narrow down the equation of state among many soft ones, although it is still possible to discriminate the true one from stiff equations of state with $R\gtrsim 13\mathrm{km}$. We also find that gravitational waves from binary neutron stars will be distinguished from those from spinless binary black holes at more than $2\sigma$ level for an event at $D_{\mathrm{eff}}=200\mathrm{Mpc}$. The validity of the EOB formalism, Taylor-T4, and Taylor-F2 approximants as the inspiral waveform model is also examined.

• Received 22 November 2015

DOI:https://doi.org/10.1103/PhysRevD.93.064082