Gamma - gamma Attenuation and Relativisitic Beaming in Gamma-Ray Bursts

Astronomy and Astrophysics – Astronomy

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

31

Gamma Rays: Bursts, Radiation Mechanisms: Miscellaneous, Relativity

Scientific paper

The observation by the BATSE experiment on board the Compton Gamma-Ray Observatory (CGRO) that the gamma-ray burst population is isotropic but inhomogeneous has dramatically bolstered the premise that most bursts are cosmological. At the same time, BATSE has also observed definite spectral breaks (Schaefer et al (1992) between 400 keV and 2 MeV in some bursts, which in three cases have been corroborated by data from EGRET. The presence of these breaks in these sources suggests attenuation by the pair production mechanism γγ → e+e-, which can absorb gamma rays, though it is suppressed when the radiation is highly beamed. In this paper, quantitative constraints that pair production places on radiation collimation in individual sources, due to the presence or absence of breaks in spectra, are presented. Cosmological bursts have extremely relativistic beaming, though the bulk Lorentz factors of their emission regions are reduced markedly for steep source spectra. Such beaming will blueshift the breaks to higher energies, indicating that those CGRO bursts displaying MeV spectral breaks may not be cosmological, or perhaps that their breaks are generated by mechanisms that dominate γ-γ attenuation at MeV energies. Alternative mechanisms for break production are discussed.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Gamma - gamma Attenuation and Relativisitic Beaming in 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 Gamma - gamma Attenuation and Relativisitic Beaming in Gamma-Ray Bursts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gamma - gamma Attenuation and Relativisitic Beaming in Gamma-Ray Bursts will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-809022

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.