high lorentz factor fireballs for high-energy grb emission€¦ · high lorentz factor fireballs...
TRANSCRIPT
Kunihito Ioka (KEK)
1. Γ>103 is possible 2. Internal shock synchro. ⇒ keV-GeV-TeV γ
3. 3-D relativistic MHD simulation (Movie only)
High Lorentz Factor Fireballs for �
High-Energy GRB Emission
KI, arXiv:1006.3073, accepted in Prog. Theo. Phys.
T. Inoue, Asano & KI, in preparation
Fermi Revolution GeV γ from GRBs GRB 090510
Abdo+ 09
GeV MeV keV
High Lorentz Factor?
γγ→e+e- (εth~MeV) – R~cΔt ⇒ τ~σTNγ/4πR2≫1 (γ-ray cannot escape)
Relativistic – R~Γ2cΔt – Blueshift – τ~Γ2β-2~Γ-6
Γ>103! v>0.999999×c
Γmin
Redshift But see also Li 08, Granot+08, Bosnjak+09, Aoi+KI 10, Zou+10
Conventional Γmax
Fireball expands by radiation pressure In principle, Γmax ~ Energy / Mass Mass↓Γmax↑… However,
⇒ Transparent before Γ~Γmax
Paczynski 86 Goodman 86 Shemi & Piran 90 Meszaros & Rees
!max =!
L!T
4"mpc3r0
"1/4
! 103L1/453 r!1/4
0,7
Matter
Radiation escapes
Nonradiative Pressure
Radiation Pressure ~ Collisionless Pressure of Relativistic Particles
~
Magnetic Field
Not escape ⇒ Γmax=Energy/Mass can be attained
e, p
KI 10
γ
p
Radiation to Collisionless
r=r0
Center
Collisional ⇒ Radiation
Dominant
Effective Proton Thermalization
Optically Thin
Matter (Proton)
Eγ>Erela_p
Radiation to Collisionless
r=r0
Center Effective Proton Thermalization
Optically Thin
Eγ≈Erela_p
Collisionless shocks via Stellar matter
entrainment or Internal shock
below photopshere
Two Body Model
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ErΓr + Mc 2 = ΓmMc2 + Em( )Γm
Er Γr2 −1 = ΓmMc
2 + Em( ) Γm2 −1
Energy
Momentum
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⇒Γm ~ErΓr2Mc 2
∝L1 2
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Er
Γr< Mc 2 < ErΓr
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Em ~ ΓmMc2 : Radiation ~ Collisionless motion
Collisionless Radiation
2 eqs. for 2 unknowns
∝r-4 ∝r-4
Fireball
Er Γr
M Em Γm
Radiation Dominated
Fireball
Dissipated Fireball
Γmax of Dissipated Fireball
Γmax~106!
KI 10 Baryon-Less Baryon-Rich
>Γconv~103
Collsionless Bulk-
Acceleration
(To be opaque)
Photosphere-Internal-External Shock Model
Photo- sphere
Internal Shock
External Shock
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νFν
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νkeV MeV GeV
e.g., Toma, Wu & Meszaros Kumar & Barniol Duran 09 Ghisellini+09, Wang+09,KI 10 Zou+ 09, Ryde & Pe’er 09
Variable Long-lived Eγ~E/2
High Γ Internal Shock
KI 10
GeV γ: Simple IS synchro. emission
TeV GeV keV
CTA ~20GeV-100TeV x10 Sensitivity Δθ~1-2 min FOV~5-10 deg ~20 s slew (LST) ~2015 (?) ~150€
TeV γ from GRB or not?
Poster 13.05 Jun Kakuwa
Photosphere-Internal-External Shock Model
Photo- sphere
Internal Shock
External Shock
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νFν
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νkeV MeV GeV
e.g., Toma, Wu & Meszaros Kumar & Barniol Duran 09 Ghisellini+09, Wang+09,KI 10 Zou+ 09, Ryde & Pe’er 09
Variable Long-lived Eγ~E/2
L∝T2
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L = 4πr02caT0
4
Epeak ~ T0
L∝T4
Yonetoku+KI 03 Amati 02
Epeak-Luminosity Relation
Stefan- Boltzmann
Dissipation ⇒ r0↑ ⇒ T↓
Thompson+ 07
Non-thermalization
Photospheric dissipation can reproduce Band
ETh~ENon-th
without fine-tune in our rela. model
Relativistic p, n may be important via pγ, nγ KI 10 Beloborodov 10
Lazzati & Begelman 10
EThermal~ ENon-th
Summary
Γ>103 is possible Internal shock synchrotron ⇒ keV-GeV-TeV γ
Hot photosphere: ETh~ENon-th
Photo.-Int.-Ext. shock model – tdelay~[rth/c~L-1/5]~R*/c~0.3sec – Neutrino – GeV γ Anti-Correlation – Max synchrotron energy ⇒ CTA
3-D Rela. MHD Simulation
T. Inoue, Asano & KI in preparation
Contact me for preprints (~10 copies)! Richtmyer-Meshkov turbulence
Magnetic Field Amplification
0.01 0.1 1 10 100
10-1
10-2
10-3
10-4
10-5
10-6
10-7
! B
time : t [ Lz/c ]
t-0.7
εB~0.1 is possible In Eddy turnover time, exponential grow + power-law decay Depends on εB,ini ⇒ Bring diversity Amplification does not depend on Δn Rela. Turbulence is not possible ΠL < 2%
T. Inoue, Asano & KI in preparation
GeV Onset Delay
Proton Thermalization Thick ⇒ Thin [Baryon-rich ⇒ Barion-less]
Max Synchrotron Energy
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′ t acc = ′ t cool
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νmaxcool =
mec2
αΓ ~ 500 GeV Γ
104
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′ t acc = ′ t dyn
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νmaxdyn ~ 1 GeV Γ
6 ×104
−6
GRB 090926 Break??
A target for CTA
Very High Lorentz Factor (VHLF) case
Wang+ 09 Piran & Nakar 10 Barniol Duran & Kumar 10
KI 10
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νFν
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νFν
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νFν
Time
MeV γ
GeV γ
TeV ν
Time
Time
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η
Time
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ηk1pp thin
pp thick
pp→π→ν εν~Γm
2mπc2>0.1TeV
TeV ν – GeV γ Anti-Correlation
Baryon-less
Baryon-rich
Necessary Mass Loading
• Ep~(Γm/rm)1/2 L1/4~L1/2 (S-B law + Yonetoku) • (Two mass collision)
⇒
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Γm ~ L˙ M c 2
1 2
M ! 10!5 M" s!1 r!2m,10
(Isotropic Rate)
Only depends on the environments Therefore, if progenitors are similar, the Epeak-L relations are reproduced