High Lorentz Factor Fireballs for High-Energy GRB Emission€¦ · High Lorentz Factor Fireballs...

of 22 /22
Kunihito Ioka (KEK) 1. Γ >10 3 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

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