Gamma-Ray Bursts &High Energy Astrophysics

Kunihito Ioka (KEK)井岡　邦仁

UniverseQuantum mechanics Dx Dp ≥ ℏGeneral relativity RBH=2GM/c2

Various scales ⇒ Order estimate

Ultimate goal ofAstrophysics is to reveal all cosmic phenomena based on physics

10301020101010010-1010-30

10-20

10-10

100

1010

1020

g/cm3

cm

Atom

r=ћ/cL4

Uncertainty lim

it

Black hole limit

r=c 2/2GL 2

Solar system

Sun

Galaxy

Universe

Neutron star

Human

QuarkNucleon

White dwarf

Cluster

Cosmic jet

L~1051erg/s~1044W» 106W (man-made)

AGN （ Active Galactic Nuclei ）

Microquasar

Pulsar

GRB

Big Puzzle

~106-9M☉BH

~10M☉BH

Neutron starC

urre

ntEnergy

Man-made accelerator

BH formation?

Cosmic rayHigh energy particles(proton, heavy nuclei)pervade the universe

Origin is unknown

Up to ~1020eV » 1013eV (man-made)

If 1g matter turns into 1020eV cosmic ray, we can supply our electric power for 105yr!

1 particle/km2/century

Bhattacharjee&Sigl 00

LHC

Cosmic rayspectrum

1020eVGeV

Flux

GRB

= =Sun~1033g

GRB~1052ergAtomic bomb

In ~sec, GRB release energy Sun emit over lifetime

GRB is the most luminous object

E=mc2 (by Einstein)

~1kg

Astronomical observationLight curve

SpectrumSky

position

Too small size

Observation+Physics ⇒ We understand cosmic phenomena

Photon (g)

Multi-wavelength: Optical (eV)

+ Radio (meV), Microwave (meV),Infrared (eV), X-ray (keV), g-ray (MeV)

GRB observation>msecLuminosity

Time

～ 1000 events/yrIsotropic sky distribution～ 200 keV, nonthermal10-3s ～ 103s : Short, Long

GRBAfterglow

XOptRadio

Cosmologicaldistance

Redshift

Supernova

~1day~10sec

The mostluminous

~1051 erg/s

Distance unknown True energy unknown⇒

Paradox?msec x c ~ 300km

1051erg/sx msec~ 1048erg

e egg

MeV g-ray numberdensity > 1029cm-3

Interaction length~(10-25x1029)-1cm~10-4cm < 300km

g-ray can not escape?g g

e+ e-

99.99% of light speed

2

1 1001 v c

Lorentz factor

Unique solution

Blue-shift

~100

1MeV10keVMeV=106eVkeV=103eVmec2~MeV

Comoving frame Observer frame

Similar to the Dopplar effect for a crossing silenLow energy g can not produce e±

Standard model

Central Engine

Massive star

SN

Internal shock

？ Inter stellarmedium

Externalshock

v>99.99%c光度

GRB時間

AfterglowKinetic energy↓

Shock dissipation

GRB ≈ BH formationGRB jet breaks out of massive stellar envelope

msec x c ~ 300km ~ BH radius

Why BH launches relativistic jet?

?

Multi-messengerLight curve

SpectrumSky

position

Too small size

Photon (g)

+ Other particles

Photon (meV-MeV) +High energy g (MeV-100TeV)Cosmic ray (GeV-1020eV)Neutrino (MeV-1019eV)Gravitational wave (nHz-kHz)

Fermi has launched!11 Jun 2008, GLAST→FermiGBM: 0.01-30MeV, 8sr, 1oresLAT: 0.02-300GeV, 2.5sr, 5o-5’res

LAT first all-sky map

Only 4day data = 1 yr data by previous mission

GBM First GRBs

31 GRBs per 1st month ( 372/yr)⇒Slightly more than predictedWithin a few degrees of Swift calculations

Blue-shift

~100

1MeV10keVMeV=106eVkeV=103eVmec2~MeV

Comoving frame Observer frame

Similar to the Dopplar effect for a crossing silenLow energy g can not produce e±

e egg

Blue-shift

~100

1GeVMeV=106eVkeV=103eVmec2~MeV

Comoving frame Observer frame

High energy g can produce e±

⇒ g flux is suppressed

10MeV

e egg

e± cutoff and line

Photon spectrum

KI+ 07Murase&KI 08

1. e± cutoff energy ⇒ Jet velocity2. e± line ⇒ e± abundance

(⇒ Jet properties ⇒ Central engine)

energy

Luminosityggee

High energy protonJet likely contains (proton, heavy nuclei) + (g, e±)

eegg cutoff

Photonspectrum

Luminosity

~GeV (109eV)Energy

>1020eV

Protonspectrum

0, g pnp cutoff

Proton interacts with g more weakly than gPion () mass > e mass ⇒ Higher energy cutoff

Cosmic ray from GRB

1 particle/km2/century

Bhattacharjee&Sigl 00

GRB could be the originof 1020eV cosmic ray!

Cosmic ray composition⇒ Jet composition (p, Fe?)⇒ Central engine

GRB energy generation rate~ CR energy generation rate

High energy neutrino

Murase,KI+(06)

Neutrino spectrum

protonn

g + m+ e+

nm ne mn ⇒ High energy n(~5% x eproton)⇒ Proton fraction⇒ Central engineStrong penetrationNot delayedCR originn interaction@>TeVt appearanceLimitting n speedEquivalence principle

IceCube

On-goingCompletion by 2011

@South pole

V~km3

Gravitational waveGW can directly “see” the central engine

Transparentfor GW

Short GRB: origin unknown

Amplitude

Time

Long GRB

Charge motion Photon⇒Mass motion GW (v=c)⇒(ripple of the space-time)

Waveform ⇔ Mass, Radius, …

Direct detection

Free mass separation changes

GW

Dx/x~GM/r~10-22

GR test: Novel prizeShort GRB originNuclear physics

Laser interferometers

TAMALIGOVIRGOGEO

~km

SummaryGRB: Most luminous objectMulti-wavelength obs.

⇒ Massive star, Relativistic jet, BH/NS

Multi-messenger obs. High energy g Cosmic Ray Neutrino Gravitational wave

⇒ Central engine (BH formation), Jet, …

High Energy AstrophysicsUnexpected may

be waiting

Livingston plotPlanck scalein ~190 yr

(J/y, t)

(gluon)

(Nn=3)(W±,Z)

(top) Man-made acceleratoris already saturating

Cosmic acceleratorcould expand theenergy frontierC

ente

r-of

-Mas

s E

nerg

y

Year

?