Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-04-10
Mon.Not.Roy.Astron.Soc.380:78,2007
Astronomy and Astrophysics
Astrophysics
18 pages 10figures, version to be published in MNRAS
Scientific paper
10.1111/j.1365-2966.2007.12051.x
Within the internal shock scenario we consider different mechanisms of high energy ($>1$ MeV) photon production inside a Gamma Ray Burst (GRB) fireball and derive the expected high energy photon spectra from individual GRBs during the prompt phase. The photon spectra of leptonic and hadronic origins are compared within different sets of parameter regimes. Our results suggest that the high energy emission is dominated by the leptonic component if fraction of shock energy carried by electrons is not very small (e.g. $\epsilon_e > 10^{-3}$). For very small values of $\epsilon_e$ the hadronic emission component could be comparable to or even exceed the leptonic component in the GeV-TeV regime. However, in this case a much larger energy budget of the fireball is required to account for the same level of the observed sub-MeV spectrum. The fireballs are therefore extremely inefficient in radiation. For a canonical fireball bulk Lorentz factor (e.g. $\Gamma=400$), emissions above $\sim 10$ GeV are attenuated by two-photon pair production processes. For a fireball with an even higher Lorentz factor, the cutoff energy is higher, and emissions of 10 TeV - PeV due to $\pi^0$-decay can also escape from the internal shocks. The flux level is however too low to be detected by current TeV detectors, and these photons also suffer attenuation by external soft photons.
Gupta Nayantara
Zhang Bing
No associations
LandOfFree
Prompt Emission of High Energy Photons from Gamma Ray Bursts does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Prompt Emission of High Energy Photons from Gamma Ray Bursts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Prompt Emission of High Energy Photons from Gamma Ray Bursts will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-672630