Cosmological Heavy Ion Collisions:Colliding Neutron Stars

Chang-Hwan Lee Hee-Suk Cho

Young-Min Kim Hong-Jo Park

ATHIC@Tsukuba

Gravitational Waves & Gamma-Ray Bursts

Colliding Neutron Stars

M = 1.5 solar mass R < 15km A = 10^57 composed of p, n, e, hyperons, quarks, …

BH

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

''

)',/'(4 34 xd

xxxcxxtT

ch

fg

Thff )21(

Tc

GRgRG 4

821

Wave Equation

0 h

Einstein Field Equation

Linearized field equation

Gravitational radiation

000000000000

)(2''

)',/'(44

'34 hh

hhcrtQ

rcGxd

xxxcxxtT

ch ij

xrxx

)(2cos)1(

4)( 24

22rt

qq

acMG

rth

Polarization amplitude

for compact binary system

4

2

5

5

5

4

5

153251

qq

aM

cG

QQcGL ijijGW

4

2

2/75

2/92/7

)1(532

qq

acMGJGW

Gravitation Wave from Binary Neutron Star

Effect of Gravitational Wave Radiation 1993 Nobel PrizeHulse & Taylor

B1913+16 Hulse & Taylor (1975)

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)

Science 308 (2005) 939

11

Gamma-Ray Burst

Duration: milli sec - min

1970s : Vela Satellite

1990s: CGRO, Beppo-SAX

2000s: HETE-II, Swift

23/05/04 12

Short-hard GRBshard

soft

short long

100010.01

No optical counterpart Origin

Neutron star merger? Magnetar flare? Supernova?

BATSESample

NS (radio pulsar) which coalesce within Hubble time (in our galaxy, near earth)

(1975)

(1990)

(2003)(2004)

(2004)

(1990)(2000)

White Dwarf companion

Possible Sources for GWR & s-GRB

• All masses are < 1.5 M⊙

side remark

Wanted Can we get some (or any) information

on NS EOS (Equation of States) from GW & GRB?

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.

Candidates for Cosmological Heavy-Ion Collisions

Neutron Star structure

Neutron Star structure

0 2 4 6 8 10 12 14 160.0

0.5

1.0

1.5

2.0

Mas

s(M

⊙)

Radius(km)

Hyperon Kaon np quark

Calculated By C.Y. Ryu @ Sungkyunkwan Univ.

Mass-Radius relation of Neutron Star

Initial mass transfer rate

18

MBH=3MSUN

Mass transfer time scale

19

MBH=3MSUN

Mass transfer time scale

20

Proto-neutron

Kaon

Quark

BH spin up (key to GRBs)

21

MBH=3MSUN

2008 Nuclear Physics School

Kaon model NP model

Hyperon model Quark model

~ 2 times high

Polarization amplitude(M⊙) after mass transfer

~ 100 times short

Kaon model Quark model

Frequency

Quark Star

Kaon-NS

Prospects

Colliding Neutron Stars: - Possibility of probing NS EOS in GW & GRBs.- At least, may be able to exclude some EOS.

Cosmological Heavy Ion Collisions

Thank you !