Abstract
We present numerical solutions of the two-dimensional relativistic hydrodynamics equations describing the deceleration and expansion of highly relativistic conical jets, of opening angles 0.05 ≤ θ0 ≤ 0.2, propagating into a medium of uniform density. Jet evolution is followed from a collimated relativistic outflow to the quasi-spherical non-relativistic phase. We show that relativistic sideways expansion becomes significant beyond the radius r θ at which the expansion Lorentz factor drops to θ-1 0. This is consistent with simple analytic estimates, which predict faster sideways expansion than has been claimed based on earlier numerical modeling. For t > ts = r θ/c the emission of radiation from the jet blast wave is similar to that of a spherical blast wave carrying the same energy (significant deviations at t ts occur only for well off-axis observers, θobs 1 ≫ θ0). Thus, the total (calorimetric) energy of gamma-ray burst blast waves may be estimated with only a small fractional error based on t > ts observations.
Original language | English |
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Article number | L23 |
Journal | Astrophysical Journal Letters |
Volume | 738 |
Issue number | 2 |
DOIs | |
Publication status | Published - 10 Sept 2011 |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science