Joint Astrophysics Colloquium

Hot Electromagnetic Outflows

Chris Thompson

CITA

Gamma-ray bursts, and other extreme forms of electromagnetic transient, are driven outward from a compact engine by a combination of the Lorentz force and radiation pressure. We present the solution to the steady wind problem in the MHD approximation, in both spherical and jet geometries. Our focus is on the regime of high radiation compactness and flow magnetization. Allowance is made for the divergence of magnetic flux surfaces following jet breakout from a confining medium. Deviations of the photon spectrum from a blackbody source are considered using a Monte Carlo approach. Implications for GRBs and other transients are discussed.