Dr. Brian Morsony (Univ. of Winsconsin) visit our group and give colloquium speech

Jan 21, 2011

gamma-ray emission. 

“The Impact of Environment on GRB and AGN Jets”

I will present numerical simulations of jet propagation in the context of GRB jets from massive stars and AGN jets in galaxy clusters.  For GRBs, the stellar envelope collimates the jet, keeping the jet hotter than would be expected for a free expansion.  This allows about 30% of the jet energy to escape as photospheric.

In AGN, interaction between the jet an a dynamic cluster environment disrupt the jet, forming multiple, disconnected X-ray bubbles from a single period of AGN activity with constant luminosity. This implies that observations of multiple bubbles in a cluster are not necessarily an expression of the AGN duty cycle.  Disruption also limits the size of the region that can be directly heated by the AGN, with implications for how AGN feedback in clusters may operate.