Gravitational waves and neutrino emission from the merger of binary neutron stars

1. Gravitational waves and neutrino emission from the merger of binary neutron stars Ref.) 1105.5035 Kenta Kiuchi Collaboration with Y. Sekiguchi, K. Kyutoku, M. Shibata

2. Introduction Our research target =high energy astrophysical phenomena e.g., Supernova energy ≈ 1.5*1046J = energy the Sun consumes for 1.2 trillion years !! SN1054 （Crab Nebula） Energy source = gravitational potential energy ∝ r-1 ～10km ～1000km r ～Solar mass

3. Products of high energy astrophysical phenomena ～10km ～3km（1 Solar mass） ✓Density～1015g/cm3(1.41 g/cm3) ⇒ General Relativity, Strong interaction ✓Temperature～1011K(15.7×106K)⇒Weak interaction ✓Magnetic fields～1015 Gauss (Sunspot：several thousand Gauss)⇒Electromagnetic force All of fundamental interaction play an essential role.

4. Physical aspects of high energy astrophysical phenomena ✓Highly dynamical ✓No special symmetry, e.g., spherical symmetry ⇒Numerical modeling including four kinds of forces Numerical Relativity Figuring out high energy astrophysical phenomena by numerically solving the Einstein equations

5. Importance of Numerical Relativity ○ Gravitational waves ✓imprinting “raw” information of sources ✓extremely weak signal, hc∼10-22 = the change of (Size of H atoms)/(Distance to Sun) GW detectors Need to prepare theoretical templates of GWs

6. Today’s topic = Coalescence of binary neutron stars ✓Promising source of GWs ✓Theoretical candidate of Short-Gamma-Ray Burst ✓High-end laboratory for Nuclear theory A nuclear theory ⇒ Mass-Radius relation for Neutron Star Mass-Radius Image of GRB Black hole + disk?

7. Overview of binary neutron star merger Rapidly rotating massive NS G.Ws. imprintonly information of mass G.Ws. imprintinformation of radius Mtotal< Mcrit NS Mtotal>Mcrit BH and torus ✓Mcritdepends on the Equation of State, i.e. Mcrit= 1.2-1.7 Mmax ✓Final massive NS or torus around BH are extremely hot, T ∼O(10) MeV⇒Neutrino cooling plays an importance role

8. Set up of binary neutron star ○Shen or Shen-Hyperon EOS based on RMF theory (Shen+,98, Sumiyoshi+,11) ⇒ Mcrit = 2.8-2.9 Solar mass for Shen, 2.3-2.4 Solar mass for Shen-Hyperon EOS ○ Neutrino cooling based on GR leakage scheme (Sekiguchi,10) ○ Equal mass model with 1.35 Solar mass, i.e., Mtot=2.7 Solar mass Mass-Radius Observed BNSs (Lattimer & Paraksh 06) Observation constraint by PSR J1614-2230

9. Result Density color contour on equatorial (x-y) plane = orbital plane In units of millisecond Log10(ρ [g/cc]) In units of Kilometer

10. Gravitational Waveforms NSs orbit around each other Massive NS oscillates Shen BH formation Shen-Hyperon

11. Gravitational Wave Spectrum Sensitivity curves for GW detectors Shen Shen-Hyperon Amplitude frequency GWs could be detected if the merger happens within 30 Mpc.

12. Neutrino Luminosity Anti electron neutrino Electron neutrino μ, τ neutrino Shen ○ ○ Neutrino cooling timescale ∼ 2-3 second ○ Huge luminosity ∼ 1053 erg/s ○ Could be detected if it happened within 10 Mpc for HK BH formation Shen+ Hyperon

13. Summary ○ Binary neutron star merger Numerical Relativity simulations with microphysical process for the first time ○ GWs could be detected if it happened within 30 Mpc ○ Neutrino could be detected if it happened within 10 Mpc ⇒ Multi messenger astronomy is coming soon !! Thanks to SR16000 in YITP Thank you for your attention