ATHIC@Tsukuba Gravitational Waves & Gamma-Ray Bursts Cosmological Heavy Ion Collisions: Colliding Neutron Stars Chang-Hwan Lee Hee-Suk Cho Young-Min Kim Hong-Jo Park
Colliding Neutron Stars BH • M = 1.5 solar mass • R < 15km • A = 10^57 • composed of p, n, e, hyperons, quarks, …
Contents • Introduction to Gravitational Wave Radiation& Gamma-Ray Bursts • Colliding Neutron Star-Black Hole System • Numerical Result
What is the GWR? Ripples in the Fabric of the Space-Time
Gravitational radiation Einstein Field Equation Linearized field equation Wave Equation
Gravitational radiation Polarization amplitude for compact binary system
Gravitation Wave from Binary Neutron Star B1913+16 Hulse & Taylor (1975) Effect of Gravitational Wave Radiation 1993 Nobel PrizeHulse & Taylor Taylor & Weisberg
GW Sources - NS-BH, NS-NS, BH-BH mergers - Cosmological perturbations - Supernovae, … • Grav. wave pattern: “Urgent Demand For GW Detection !!”
Laser Interferometer Gravitational Wave Observatory LIGO I : in operation (since 2004) LIGO II: in progress (2014)
Gamma-Ray Burst 1970s : Vela Satellite 1990s: CGRO, Beppo-SAX 2000s: HETE-II, Swift Duration: milli sec - min
Short-hard GRBs • hard • BATSE • Sample • No optical counterpart • Origin • Neutron star merger? • Magnetar flare? • Supernova? • short • long • soft • 0.01 • 1000 • 1
Possible Sources for GWR & s-GRB NS (radio pulsar) which coalesce within Hubble time (in our galaxy, near earth) (2003)(2004) (1990) (2004) (1975) (1990)(2000) White Dwarf companion
side remark • All masses are < 1.5 M⊙
Candidates for Cosmological Heavy-Ion Collisions • NS-NS binaries : seen several • NS-BH binaries : some clues • BH-BH binaries : expected in globular clusters where old-dead stars (NS, BH) are populated. Wanted • Can we get some (or any) information on NS EOS (Equation of States) from GW & GRB?
Neutron Star structure Mass-Radius relation of Neutron Star Calculated By C.Y. Ryu @ Sungkyunkwan Univ.
Initial mass transfer rate MBH=3MSUN
Mass transfer time scale MBH=3MSUN
Mass transfer time scale Proto-neutron Kaon Quark
BH spin up (key to GRBs) MBH=3MSUN
Polarization amplitude of GW • Kaon model • NP model • Hyperon model • Quark model 2008 Nuclear Physics School
Polarization amplitude(M⊙) after mass transfer Quark model Kaon model ~ 2 times high ~ 100 times short
Frequency Quark Star Kaon-NS
Cosmological Heavy Ion Collisions Prospects • Colliding Neutron Stars: - Possibility of probing NS EOS in GW & GRBs.- At least, may be able to exclude some EOS. Thank you !