Kunihito IOKA (Osaka Univ.)1. Observation2. Fireball3. Internal shock4. Afterglow5. Jet

6. Central engine7. Links with other fields8. Luminosity-lag9. X-ray flash10. Summary

1. ObservationGamma-Ray Burst

Brightest object 15210 s ergs

Vela satellites in 1967

Origin has been a puzzle

                                                

                         

～ 1000 events/yr

Angular distributionIsotropic

Spatial distribution

3 2N P P Homogeneous in Euclidean

max 0.330 0.010V V

Inhomogeneous

Duration

Long-softShort-hard

Long burstShort burst

SpectrumBand spectrum

Non-thermal

AfterglowBeppo-SAX in 1997

X-ray

Radio

Optical → RedshiftRedshift

Luminosity

Time

GRB

Summary of observation

～ 1000 events/yrIsotropic, Inhomogeneous～ 200 keV10-3s ～ 103s : short, long

AfterglowX-rayOpticalRadio

Redshift

>msec

2. FireballCompactness problem

810 10ms cmR c T T 2 49

7 2810 ergE FD F D e e 2 22

133 2 7 2

1010 erg cm 3Gpc 10msT

e

FD F D TR

R m c

Optically thick Non-thermal

MeVE

1Relativistic motion

2R E

N

MeV MeV

4 6.5B

210

FireballiRE

1 4 3 452 ,710 MeVi iT E R

3 3entropy const constT R

2exp 20keV:thine B pn m c k T T

9 1 4 1 452 ,76 10 cmi p i iR T T R E R

4 3energy const const iT R R R obs iT T T +Baryon

3bn R 14 1 2 1 2

52 21 10 cmthinR E

2E Mc

92 ,71 10 cm : Matter dominantmatter i iR R R 2E Mc

10 5 10

5

10 : Pure radiation 10 < <10 : Electron dominated

1< <10 : Relativistic baryon <1: Newtonian

Thermal

Ｃｅｎｔｒａｌ ｅｎｇｉｎｅ

Ｏｐｔｉｃａｌｌｙ ｔｈｉｃｋ ｒｅｇｉｏｎ

Ｉｎｔｅｒｎａｌ ｓｈｏｃｋｓ

Ｅｘｔｅｒｎａｌ ｓｈｏｃｋｓ

？

ＩＳＭ

1Γ 1Γ

eeγγ

Internal-External shock model

time

Luminosity Kinetic energy

Shock dissipation

3. Internal shock

r

Two shell collision

s m

rm sm mm

2 2

2

1 1

1

r r s s r s m m

r r s s

r s m m

m m m m E

m m

m m E

efficiency : 1 r s m

r r s s

m m

m m

: 0.5 when 13.9r s r sm m

Kobayashi,Piran&Sari(97)

Many shell

Time scale

2

c T

2 1310 cmR c T 1

2R

2

RT

c

Pulse width

22

c T

Pulse interval

T

Nakar&Piran(02)

4. Afterglow

r

External shock

m

rm sm mm

2m r s r rm m 34

3s pm R nm

2 3 2 24

3r r p rE m c R nm c

16 1 3 2 3 1 351 2 010 cmR E n

Hydrodynamics3 2 24

3 pE R nm c n

R3 8T

2T R

① Electron Fermi acceleration 2.21 , (Fermi acc.)e e e eU U O N

1B BU U O ② Magnetic field

Relativistic shock

n2 ,n U

2

2

4 3

1 p

n n

U nm c

Jump condition

Electron synchrotron emission1/3

F

22 2

22

4

3 8e T e

e ee

BF c

qB

m c

Spectrum

,max

, , ,

, , ,

e B

a m c

E n

F

52

3

10 erg

0.1 50cm

0.1

0.01e

B

E

n

Collapsar, Hypernova

ｒｅｖｅｒｓｅ ｓｈｏｃｋｆｏｒｗａｒｄ ｓｈｏｃｋ

Shock emission

Optical flash

5. JetJet & Relativistic beaming

1・ Relativistic beaming・ Jet

1Γ

Jet in afterglow11 ΓθΓθθ ii ：ｓｉｄｅｗａｙｓ ｅｘｐａｎｓｉｏｎ

iθ

Energy, Event rate, Model

3 2 2 24

3 pE R nm c

2 2T R

Total

Break in afterglowPolarizationA few %

Total energy

5110 ergE

6. Central engine① Ｃｏｌｌａｐｓｅ ｏｆ ｍａｓｓｉｖｅ ｓｔａｒ

② Ｍｅｒｇｅｒｓ ｏｆ ｃｏｍｐａｃｔ ｏｂｊｅｃｔｓ・Ｂａｒｙｏｎ ｆｒｅｅ

・Ｌｏｃａｔｉｏｎ ｗｉｔｈｉｎ ｈｏｓｔ ｇａｌａｘｉｅｓ・ＧＲＢ - Ｓｕｐｅｒｎｏｖａ （ｅ . ｇ . ，ＳＮ１９９８ｂｗ）？Ｈｉｇｈ ａｍｂｉｅｎｔ ｇａｓ ｄｅｎｓｉｔｙ

？？？？

Collapsar, Hypernova

Host galaxy

SN1998bw-GRB980425 46 65.5 0.7 10 erg/s : 10 dimL

Lightcurve Fe line

7. Links with other fieldsCR, HE, HE

44 3

19 21

10 erg/Mpc /yr

UHECR (10 - 10 eV)

Cosmology

8. Luminosity-lag

X

Ｌｕｍｉｎｏｓｉｔｙ

Ｔｉｍｅ

Ｔｉｍｅ

TΔ

peakL

TΔ Lpeak ・Ｓｔａｎｄａｒｄ ｃａｎｄｌｅ ？・Ｂｒｉｇｈｔｅｒ ｔｈａｎ ＳＮｅ Ia・Ｌｅｓｓ ｅｘｔｉｎｃｔｉｏｎ

ApJ,554,L163(01)

Viewing angle of a single jet

？

？

？

⇒ Ｌｕｍｉｎｏｓｉｔｙ - ｌａｇ ｒｅｌａｔｉｏｎ ？

Thin jet

’’ ’

0 0 0ν

vv

v

j r, t A f ν t t r r

cos θ cosθ cosθH θ θ θ H cos

sinθ sinθ

ＥｍｉｓｓｉｖｉｔｙθΔ

vθ

Bβ -α /sα s’ ’

’’ ’0 0

ν νf ν =

ν ν

ＢＢ１＋

１＋

～Ｂａｎｄ ｓｐｅｃｔｒｕｍ

B B1, 1, 2.5, s 1

Ｓｐｅｃｔｒｕｍ ’’ｆνν

’ν Bαν

2’

Bβν

2’

20 0

ν 22 2

00

Δ T2cA r γF T = f νγ 1 βcosθ T

D γ 1 βcosθ T

cβwhere 1 βcosθ T = T T

r

Luminosity-Lag Relationv 0 1

v 2

1v

Lag:

Pulse profile

Luminosity-width

ＦＲＥＤ（Ｆａｓｔ Ｒｉｓｅ Ｅｘｐｏｎｅｎｔｉａｌ Ｄｅｃａｙ）

8232

.

obs

BκFWHM

peakν

κ: nobservatioακ where WFν

Viewing angle① Ｐｅａｋ ｌｕｍｉｎｏｓｉｔｙ - ｓｐｅｃｔｒａｌ ｌａｇ ｒｅｌａｔｉｏｎ② Ｐｅａｋ ｌｕｍｉｎｏｓｉｔｙ - ｖａｒｉａｂｉｌｉｔｙ ｒｅｌａｔｉｏｎ③ Ｌｕｍｉｎｏｓｉｔｙ - ｗｉｄｔｈ ｒｅｌａｔｉｏｎ

GRB980425Ａ ｔｙｐｉｃａｌ ＧＲＢ⇒ Ａｓｓｏｃｉａｔｉｏｎ ｏｆ ＧＲＢｓ ｗｉｔｈ ＳＮｅ

9. X-ray flash

Off-axis GRB

Flux/Fluence RatioApJ,571,L31(02)

3 1 3 2 2 110 yr 5 3 10 yr Volume Viewing angle

10. SummaryGRB : Internal shockAfterglow : External shockJetViewing angle

Various relations, X-ray flashCentral engine ???

Collapsar? Merger?CR, HE, HE, GW, Cosmology