Exploring tidal effects in coalescing binary neutron stars in numerical relativity

by Dr Koutarou Kyutoku (RIKEN)

Monday 25 May 2015, 15:00 → 16:00 Asia/Tokyo

Main Research bldg. 433 (RIKEN Wako)

Date: May 25 (Mon)
Time: 15:00 -
Place: Main Research bldg. 433
Speaker: Koutarou Kyutoku (RIKEN)

Title: Exploring tidal effects in coalescing binary neutron stars in numerical relativity

Abstract: Coalescences of binary composed of two neutron stars---binary neutron stars---are one of the most promising gravitational-wave sources for ground-based laser-interferometric detectors such as Advanced LIGO (United States) and KAGRA (Japan). Advanced LIGO will begin operations from this year, and KAGRA will join the observation in this decade. Once the detection becomes a routine, gravitational-wave astronomy will serve as an important tool to study unexplored physics such as properties of neutron stars and supranuclear-density material. In particular, tidal deformability (strongly related to the radius) governs tidal deformation of neutron stars in a binary, which modifies the orbital dynamics and gravitational waves from those of binary black holes. To extract neutron-star properties from gravitational waves, it is necessary to prepare accurate theoretical waveforms (usually called templates) from binary neutron star coalescences. However, it is a hard task to derive accurate waveforms for the entire coalescence process, because the merger involves rapid variation of spacetimes sourced by strongly-gravitating hydrodynamical objects. Here, numerical relativity (i.e., fully general relativistic simulations) is the most reliable way to study the late inspiral and merger phases, where tidal interaction plays a substantial role. In this talk, I will summarize the current status of template preparations and present recent results obtained by our numerical-relativity simulations.

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