Open AccessEvents in the life of a cocoon surrounding a light, collapsar jet
Author(s) -
RamirezRuiz Enrico,
Celotti Annalisa,
Rees Martin J.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05995.x
Subject(s) - physics , astrophysics , afterglow , outflow , jet (fluid) , shock wave , gamma ray burst , kinetic energy , envelope (radar) , shock (circulatory) , plasma , explosive material , astrophysical jet , astronomy , collimated light , mechanics , active galactic nucleus , laser , optics , classical mechanics , nuclear physics , medicine , telecommunications , radar , chemistry , organic chemistry , galaxy , meteorology , computer science
According to the collapsar model, γ‐ray bursts are thought to be produced in shocks that occur after the relativistic jet has broken free from the stellar envelope. If the mass density of the collimated outflow is less than that of the stellar envelope, the jet will then be surrounded by a cocoon of relativistic plasma. This material would itself be able to escape along the direction of least resistance, which is likely to be the rotation axis of the stellar progenitor, and to accelerate in approximately the same way as an impulsive fireball. We discuss how the properties of the stellar envelope have a decisive effect on the appearance of a cocoon propagating through it. The relativistic material that accumulated in the cocoon would have enough kinetic energy to substantially alter the structure of the relativistic outflow, if not in fact provide much of the observed explosive power. Shock waves within this plasma can produce γ‐ray and X‐ray transients, in addition to the standard afterglow emission that would arise from the deceleration shock of the cocoon fireball.