RELATIVISTIC JET DYNAMICS AND CALORIMETRY OF GAMMA-RAY BURSTS

Journal Article · Sat Sep 10 04:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/738/2/L23· OSTI ID:21562431

Wygoda, N; Waxman, E ^[1]; Frail, D A ^[2]

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1. Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel)
2. National Radio Astronomy Observatory, Array Operations Center, Socorro, NM 87801 (United States)

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 {<=} {theta}{sub 0} {<=} 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{sub {theta}} at which the expansion Lorentz factor drops to {theta}{sup -1}{sub 0}. This is consistent with simple analytic estimates, which predict faster sideways expansion than has been claimed based on earlier numerical modeling. For t > t{sub s} = r{sub {theta}}/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 {approx} t{sub s} occur only for well off-axis observers, {theta}{sub obs} {approx} 1 >> {theta}{sub 0}). Thus, the total (calorimetric) energy of gamma-ray burst blast waves may be estimated with only a small fractional error based on t > t{sub s} observations.

• OSTI ID: 21562431
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 738; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
CALORIMETRY
COSMIC GAMMA BURSTS
COSMIC RADIATION
EMISSION
EVOLUTION
EXPANSION
EXPLOSIONS
FLUID MECHANICS
HYDRODYNAMICS
IONIZING RADIATIONS
JETS
MATHEMATICAL SOLUTIONS
MECHANICS
NUMERICAL SOLUTION
PRIMARY COSMIC RADIATION
RADIATIONS
TWO-DIMENSIONAL CALCULATIONS