Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 1

Relativistic interaction of a high intensity photon beam with a

plasma: a possible GRB emission

mechanism

L. Amati, G. Barbiellini, A Celotti, A. Galli, R. Landi, F. Longo, N. Omodei, M. Tavani

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 2

Bright and Dim GRB(Connaughton 2002)

Q = cts/peak cts

BRIGHT GRB DIM GRB

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 3

The Compton Tail

Barbiellini et al. (2004) MNRAS 350, L5

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 4

The Compton tail

“Prompt” luminosity

Compton “Reprocessed” luminosity

“Q” ratio

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 5

Bright and Dim Bursts

Bright bursts (tail at 800 s) Peak counts >1.5 cm-2 s-1 Mean Fluence 1.5 10-5 erg cm-2

Q = 4.0 0.8 10-4 (5 ) fit over PL

= 1.3 Dim bursts (tail at 300s)

peak counts < 0.75 cm-2 s-1

Mean fluence 1.3 10-6 erg cm-2

Q = 5.6 1.4 10-3 (4 ) fit over PL

=2.8

“Compton” correction

R = 1015 cmR ~ R ~ 0.1

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 6

WakeField Acceleration

(Ta Phuoc et al. 2005)

Laser Pulse tlaser = 3 10-14 sLaser Energy = 1 JouleGas Surface = 0.01 mm2

Gas Volume Density = 1019 cm3

Power Surface Density W= 3 1018 W cm-2

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 7

WakeField Acceleration(Ta Phuoc et al. 2005)

Emitted Photon SpectrumElectron Spectrum

Simulated Photon Spectrum

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 8

r0 ~ n-1/3 1/2

b~ n-1/21/2

p~ n-1/2

Scaling relations

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 9

Scaling relations

V ~ r03 ~ n-1

Q+=enr03~n0

~n-1/3

Ep = 3/4 hc2 r0/p2

(1019) ~ 102

(109) ~ 2x105

(102) ~ 2x108

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 10

3D PIC Simulation

PhD Thesis Marco Galimberti 2003 Pisa

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 11

GRB Gamma Emission in the stochastic wake field acceleration

regime

From the equation of the electron energy loss we derive

Re ~ 4.1p (pre

)2 / 31/ 6

Imposing Re = R, we link the jet angle to an energy threshold t

t 1.2(pre

)2 / 7 j 6 / 7

The previous relations allow the prediction of the typical energy emission

i rob

eff2 (

R

b)i

2

Rr0

2

p3 (2) 1.5 j

2

R () 2 2p j25 / 2

E peak eff 25n

109 j 8 / 7keV 350keV

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 12

Condition for the realization of the SWFA regime

N(R) 2ct pR

2 2 1

E(R) E(R0 )F(R)

N(R) E(R)

Ep

prec

F(R) e

n0R0 1R0

R0 (R)

R02 1 R0

R0(R)

2

Precursor Photon interaction condition

Energy Attenuation

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 13

Prediction (1) X-ray light curve for prompt and afterglow emission

(R. Willingale astro-ph/0612031)

secs after peakErgs cm-2s-1 0.3-10 keV

TaTp

n0(R0 )

n(Ra )i)

ii)

Tp R0

2

24c

a 1

2 p

p n0R0 T

n0 1.61014 p2m 3

R0 61013 p 1m

2 10 4 Tp p

1 z

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 14

Prediction (2)

Spectral geometrical correlation:

Ep T

1 z

4

7

Eiso T

1 z

27

28

Spectral-Energy correlation:

Eiso0.59

Ep cost (Amati relation: )

(L. Amati Il Nuovo Cimento)

Eiso0.58

Ep cost

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 15

Predictions (3)

Low Ep

GRB

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 16

Predictions (4)

Low Ep

GRB

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 17

Conclusions

Jetted structure of GRB Presence of Material around GRB Compton tail measurement Plasma acceleration mechanism Laboratory vs Astrophysics Cosmology with Spectral – Energy correlations?

Backup

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 19

GRB tails

Connaughton (2002), ApJ 567, 1028 Search for Post Burst emission in prompt GRB energy

band Looking for high energy afterglow (overlapping with

prompt emission) for constraining Internal/External Shock Model

Sum of Background Subtracted Burst Light Curves Tails out to hundreds of seconds decaying as temporal

power law = 0.6 0.1 Common feature for long GRB Not related to presence of low energy afterglow

Guido Barbiellini GLAST Symposium Stanford, February, 7th 2007 20

WakeField Acceleration

(Ta Phuoc et al. 2005)