Gamma-Ray Bursts from Radiation-Dominated Jet?

Kunihito Ioka (KEK)

T. Inoue, Asano & KI, arXiv: 1011.6350KI, arXiv: 1006.3073Suwa & KI, arXiv: 1009.6001KI+, in preparation (arXiv: 1103.5746)

Sorry for changing the titleto a preliminary studyComments welcome

Baryon LoadingG or r/r0

h=E/Mc2h*~103

G*

~103

Photon-to-Baryon

Radiation-Dominated

Matter-Dominated

Paczynski, GoodmanMeszaros & ReesShemi & Piran

Baryon LoadingG or r/r0

h=E/Mc2h*~103

G*

~103

IS Synchro.Photosphere

OriginalPaczynskiGoodman

Photon-to-Baryon

CompactnessNon-thermal

Except Zhang & Yan 11, KI 10,Tchekhovskoy+ 10, McKinney 10,

Gianinnos+ 07 (& others?)

BeloborodovVurm, DaigneMedvedev,Ryde, Lundman

~102

Fermi RevolutionGeV g from GRBs

GRB 090510

Abdo+ 09

GeVMeVkeV

Baryon LoadingG or r/r0

h=E/Mc2h*~103

G*

~103

IS Synchro.Photosphere

Fermi limit

Photon-to-Baryon

OriginalPaczynskiGoodman

But, Hascoet+ 11Zou+ 10, Aoi+ 10

OmodeiRacusinGhiselliniBB Zhang

Baryon LoadingG or r/r0

h=E/Mc2h*~103

G*

~103

IS Synchro.Photosphere

Fermi limit

Photon-to-Baryon

OriginalPaczynskiGoodmanFine Tuning?

OmodeiRacusinGhiselliniBB Zhang

Internal Shock in RD?Time (t)

Space (r)r0

€

Γ∝ r

€

~r0

2cΓ02

~ Causal

Light path

⇒ No Internal Shock

Rapid Shell

Slow

She

ll

Confinement

€

Γ∝ r ⇒ Γ ∝ rλ , λ <1

€

θ ∝ rλ −1

€

′ V ∝θ 2r2ΓΔ ∝ r2λΓ

′ T ∝ ′ V −1 3 adiabatic( )

Γ ′ T 4 ′ V = const

External pressureor Magnetic

TchekhovskoyNarayan

Internal Shock in RD?Time (t)

Space (r)r0

€

Γ∝ r

€

~r0

2cΓ02

~ Causal

Light path

⇒ No Internal Shock

Internal Shock in RD!Time (t)

Space (r)r0

€

Γ∝ rλ , 1

2< λ < 1

€

~r0

2cΓ02

~ Causal

Light path

Internal Shock in RD!Time (t)

Space (r)r0

€

Γ∝ rλ , 0 < λ ≤1

2

€

~r0

2cΓ02

~ Causal

Light pathAll rapid shells can catch-uplike IS

r/G2 always increases (so trivial)

Poynting models

Internal Shock of RD Flow

1. Internal Shock is possible for RD outflow2. Up to a large radius3. Repeatedly

⇒ Can keep e±

up to high G

Cocoon Confinement

€

ρ* ∝ r−n

Pressure balance at1.Jet head2.Cocoon-Star3.Jet-Cocoon

€

λ ~4 + n

14~1/2 for n=3 (Rad. env.)

⇒ Dissipative

€

Γ∝ rλ , θ ∝ rλ −1

Aloy+ 00, Lazzati+ 09, Morsony+ 10, Mizuta+ 10

Cocoon Confinement

€

ρ* ∝ r−n

€

Γ∝ rλ , θ ∝ rλ −1 Pressure balance at1.Jet head2.Cocoon-Star3.Jet-Cocoon

€

λ ~4 + n

14~1/2 for n=3 (Rad. env.)

⇒ DissipativeAloy+ 00, Lazzati+ 09, Morsony+ 10, Mizuta+ 10

Fast Cocoonjust escaping from the jet head

sideways at the breakout

Gfc~Gj(tbreak)~10-30

pfc~r-8/3

pj~r-4

€

λ ~2

3

⇒ Confine

⇒ persist around the jet

⇒ Internal Shock

€

Γ∝ rλ

Shock ⇒ g acceleration ⇒ e±

• Photons carries almost all the energy• Shock via Compton (g mediated

shock)• Fermi-like acceleration of photons• y-parameter can be of unity• Appreciable energy can go to gg→e±

• Outflow can keep e± tT~Dt’shock/t’dyn>1electron/positronDensityor G

Blandford & Payne 78

Budnik+ 10

Turbulence

T. Inoue, Asano & KI 11

A small Dn is enough to drive turbulenceRichtmyer-Meshkov turbulence

3D Rela. MHD Thompson 94

Lorentz Factor

l=2/3 in the last eq.

If e± are kept by internal shocksout to e± photosphere

High Lorentz Factorc.f. KI(10) for baryonic case

Extended g-GenerationPhoto-sphere

Radiation-Dom.InternalShock

€

νFν

€

νMeV GeV

~GGrel2mec2

€

τT ∝r

Γ 2∝ r1−2λ ~ r−1/ 3

Shocks would continue beyond photosphere

CTA ~20GeV-100TeV x10 Sensitivity Dq~1-2 min FOV~5-10 deg ~20 s slew (LST) ~2015 (?) ~150€

TeV g from GRB or not?

O’BrienGranotS. Inoue

SummaryG or r/r0

h=E/Mc2h*~103

G*

~103

IS Synchro.Photosphere

Fermi limit

Photon-to-Baryon

OriginalPaczynskiGoodmanFine Tuning?

Summary

OriginalPaczynskiGoodman

G or r/r0

h=E/Mc2h*~103

G*

~103

IS Synchro.Photosphere

Fermi limit

Photon-to-Baryon

UnexploredFrontier?RD Internal Shock via

Confinement

Implications

• Lorentz factor: Cutoff probed by CTA• Non-thermal spectrum ~ Band• Extended g generation, deep inside g-

sphere• Early afterglow, High efficiency is

possible• GeV lag ~ rphotosphere/cGfc

2

• UHECR, neutrino• Magnetic field dissipation• Blandford-Znajek McKinney

T. Inoue, Asano & KI 11

f=1.8

B Amplification & Decay behind shock

Most Ancient Object

A massive star’s death just 600 Myr after the Big Bang

GRB 090423@ z~8.2

First GRB

Pop III(Zero Metal)

~100-1000M(!?)

Present Day Massive Star

~20M

Abel+ 02Bromm+ 02Omukai+ 03Yoshida+ 08

Gigantic (x100) GRB @ z~10-30???

Komissarov & Barkov 10Meszaros & Rees 10

Massive Envelope

Ohkubo+ 09Heger+ 03Suwa & KI 10

No mass loss via line driven wind

R/c~103s > TGRB~10s⇒ No GRB?

Core Envelope

Envelope Accretion

Suwa & KI 10

• Energetic• Very long• Modest L

Bright phase⇒ Cocoon

€

L∝ ˙ M ⇒ vJet head

Analytic Expressions

GRB jet can breakout the first star!