Astrophysical applications of Delbruck scattering: Dust scattered gamma radiation from gamma ray bursts

作者：Kunwar B^*; Bhadra A; Sen Gupta S K

来源：Radiation Physics and Chemistry, 2014, 95: 326-328.

DOI：10.1016/j.radphyschem.2012.12.019

• Delbruck scattering
• GRB
• Molecular dust

A preliminary, and perhaps the first, study of astrophysical applications of Delbruck scattering in a gamma-ray emitting celestial object like a gamma-ray burst (GRB) has been made. At energies 100 MeV the elastic scattering of gamma-ray photons off the molecular dust surrounding the GRB site is dominated by Delbruck scattering. Expressions for Delbruck-scattered gamma-ray flux as a function of time has been obtained for a few selected energies by assuming a simple model of GRB. These are compared with Compton-scattered flux. At certain situations, interestingly, the former is found to exceed the latter for the first few milliseconds of the burst. The issue of detectability of Delbruck-scattered gamma-ray echo from the cloud of a GRB is discussed. Although it is observed that the detection of such an echo is not within the capability of the presently operating gamma-ray missions such as Fermi LAT, a rough estimate shows that one can be optimistic that future generation gamma-ray telescopes might be able to see such photons' contribution to the total flux.

• 出版日期2014-2