Some implications of inverse-Compton scattering of hot cocoon radiation by relativistic jets in gamma-ray bursts

Long gamma-ray bursts (GRBs) relativistic jets are surrounded by hot cocoons which confine jets during their punch out from the progenitor star. These cocoons are copious sources of X-ray photons that can be and are inverse-Compton (IC) scattered to MeV–GeV energies by electrons in the relativistic jet. We provide detailed estimates for IC flux resulting from various interactions between X-ray photons and the relativistic jet, and describe what we can learn about GRBs jets and progenitor stars from the detection (or an upper limit) of these IC scattered photons.