High Lorentz Factor Fireballs for High-Energy GRB Emission€¦ · High Lorentz Factor Fireballs...
of 22
/22
Embed Size (px)
Transcript of High Lorentz Factor Fireballs for High-Energy GRB Emission€¦ · High Lorentz Factor Fireballs...
-
Kunihito Ioka (KEK)
1. Γ>103 is possible2. 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 RevolutionGeV γ from GRBsGRB 090510
Abdo+ 09
GeVMeVkeV
-
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
RedshiftBut 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 86Goodman 86Shemi & Piran 90Meszaros & Rees
Γmax =(
LσT4πmpc3r0
)1/4∼ 103L1/453 r
−1/40,7
Matter
Radiationescapes
-
Nonradiative Pressure
Radiation Pressure ~Collisionless Pressure of Relativistic Particles
~
MagneticField
Not escape ⇒ Γmax=Energy/Mass can be attained
e, p
KI 10
γ
p
-
Radiation to Collisionless
r=r0Center
Collisional⇒ Radiation
Dominant
Effective Proton Thermalization
Optically Thin
Matter (Proton)
Eγ>Erela_p
-
Radiation to Collisionless
r=r0Center Effective Proton
ThermalizationOptically Thin
Eγ≈Erela_p
Collisionless shocksvia Stellar matter
entrainmentor Internal shock
below photopshere
-
Two Body Model
€
ErΓr + Mc2 = ΓmMc
2 + Em( )ΓmEr Γr
2 −1 = ΓmMc2 + Em( ) Γm2 −1
Energy
Momentum
€
⇒Γm ~ErΓr2Mc 2
∝L1 2
€
ErΓr
< Mc 2 < ErΓr
€
Em ~ ΓmMc2 : Radiation ~ Collisionless motion
Collisionless Radiation
2 eqs. for2 unknowns
∝r-4 ∝r-4
Fireball
ErΓr
MEmΓm
RadiationDominated
Fireball
DissipatedFireball
-
Γmax of Dissipated Fireball
Γmax~106!
KI 10Baryon-LessBaryon-Rich
>Γconv~103
CollsionlessBulk-
Acceleration
(To be opaque)
-
Photosphere-Internal-External Shock Model
Photo-sphere
InternalShock
ExternalShock
€
νFν
€
νkeV MeV GeV
e.g., Toma, Wu & MeszarosKumar & Barniol Duran 09Ghisellini+09, Wang+09,KI 10Zou+ 09, Ryde & Pe’er 09
Variable Long-livedEγ~E/2
-
High Γ Internal Shock
KI 10
GeV γ:Simple IS synchro.emission
TeVGeVkeV
-
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 13.05Jun Kakuwa
-
Photosphere-Internal-External Shock Model
Photo-sphere
InternalShock
ExternalShock
€
νFν
€
νkeV MeV GeV
e.g., Toma, Wu & MeszarosKumar & Barniol Duran 09Ghisellini+09, Wang+09,KI 10Zou+ 09, Ryde & Pe’er 09
Variable Long-livedEγ~E/2
-
L∝T2
€
L = 4πr02caT0
4
Epeak ~ T0
L∝T4
Yonetoku+KI 03Amati 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 10Beloborodov 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
ε B
time : t [ Lz/c ]
t-0.7 εB~0.1 is possible In Eddy turnovertime, exponential grow + power-lawdecay Depends on εB,ini⇒ Bring diversity Amplification doesnot depend on Δn Rela. Turbulenceis not possible ΠL < 2%
T. Inoue, Asano & KI in preparation
-
GeV Onset Delay
Proton Thermalization Thick ⇒ Thin[Baryon-rich ⇒ Barion-less]
-
Max Synchrotron Energy
€
′ t acc = ′ t cool
€
νmaxcool =
mec2
αΓ ~ 500 GeV Γ
104
€
′ t acc = ′ t dyn
€
νmaxdyn ~ 1 GeV Γ
6 ×104
−6
GRB 090926 Break??
A target for CTA
Very High Lorentz Factor (VHLF) case
Wang+ 09Piran & Nakar 10Barniol Duran & Kumar 10
KI 10
-
€
νFν
€
νFν
€
νFν
Time
MeV γ
GeV γ
TeV ν
Time
Time
€
η
Time
€
ηk1pp thin
pp thick
pp→π→νεν~Γm2mπc2>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)
⇒
€
Γm ~L˙ M c 2
1 2
Ṁ ∼ 10−5 M" s−1 r−2m,10(Isotropic Rate)
Only depends on the environmentsTherefore, if progenitors are similar,the Epeak-L relations are reproduced
