gamma-ray bursts from radiation-dominated jet? kunihito ioka (kek) t. inoue, asano & ki, arxiv:...
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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!