With this paper we introduce the concept of apparent structure of a gamma-ray burst (GRB) jet, as opposed to its intrinsic structure. The latter is customarily defined specifying the functions ε{lunate}(θ) (the energy emitted per jet unit solid angle) and Γ(θ) (the Lorentz factor of the emitting material); the apparent structure is instead defined by us as the isotropic equivalent energy E<inf>iso</inf>(θ<inf>v</inf>) as a function of the viewing angle θ<inf>v</inf>.We show how to predict the apparent structure of a jet given its intrinsic structure. We find that a Gaussian intrinsic structure yields a power-law apparent structure: this opens a new viewpoint on the Gaussian (which can be understood as a proxy for a realistic narrow, well-collimated jet structure) as a possible candidate for a quasi-universal GRB jet structure. We show that such a model (a) is consistent with recent constraints on the observed luminosity function of GRBs; (b) implies fewer orphan afterglows with respect to the standard uniform model; (c) can break out the progenitor star (in the collapsar scenario) without wasting an unreasonable amount of energy; (d) is compatible with the explanation of the Amati correlation as a viewing angle effect; (e) can be very standard in energy content, and still yield a very wide range of observed isotropic equivalent energies.

Salafia, O., Ghisellini, G., Pescalli, A., Ghirlanda, G., Nappo, F. (2015). Structure of gamma-ray burst jets: Intrinsic Versus apparent properties. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 450(4), 3549-3558 [10.1093/mnras/stv766].

Structure of gamma-ray burst jets: Intrinsic Versus apparent properties

SALAFIA, OM SHARAN
Primo
;
GHISELLINI, GABRIELE
Secondo
;
Ghirlanda, G;
2015

Abstract

With this paper we introduce the concept of apparent structure of a gamma-ray burst (GRB) jet, as opposed to its intrinsic structure. The latter is customarily defined specifying the functions ε{lunate}(θ) (the energy emitted per jet unit solid angle) and Γ(θ) (the Lorentz factor of the emitting material); the apparent structure is instead defined by us as the isotropic equivalent energy Eisov) as a function of the viewing angle θv.We show how to predict the apparent structure of a jet given its intrinsic structure. We find that a Gaussian intrinsic structure yields a power-law apparent structure: this opens a new viewpoint on the Gaussian (which can be understood as a proxy for a realistic narrow, well-collimated jet structure) as a possible candidate for a quasi-universal GRB jet structure. We show that such a model (a) is consistent with recent constraints on the observed luminosity function of GRBs; (b) implies fewer orphan afterglows with respect to the standard uniform model; (c) can break out the progenitor star (in the collapsar scenario) without wasting an unreasonable amount of energy; (d) is compatible with the explanation of the Amati correlation as a viewing angle effect; (e) can be very standard in energy content, and still yield a very wide range of observed isotropic equivalent energies.
Articolo in rivista - Articolo scientifico
radiation mechanisms: non-thermal, relativistic processes, gamma-ray burst: general
English
2015
450
4
3549
3558
reserved
Salafia, O., Ghisellini, G., Pescalli, A., Ghirlanda, G., Nappo, F. (2015). Structure of gamma-ray burst jets: Intrinsic Versus apparent properties. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 450(4), 3549-3558 [10.1093/mnras/stv766].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/84092
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