GRB afterglow blast wave encountering sudden circumburst density change produces no flares

I. Gat, H. van Eerten, A. MacFadyen

Research output: Contribution to conferencePaper

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Abstract

Afterglows of gamma-ray bursts are observed to produce light curves
with the flux following power law evolution in time. However, recent observations reveal bright flares at times on the order of minutes to days.
One proposed explanation for these flares is the interaction of a relativistic
blast wave with a circumburst density transition. In this paper, we model
this type of interaction computationally in one and two dimensions, using
a relativistic hydrodynamics code with adaptive mesh refinement called
ram, and analytically in one dimension. We simulate a blast wave traveling
in a stellar wind environment that encounters a sudden change in
density, followed by a homogeneous medium, and compute the observed
radiation using a synchrotron model. We show that flares are not observable
for an encounter with a sudden density increase, such as a wind
termination shock, nor for an encounter with a sudden density decrease.
Furthermore, by extending our analysis to two dimensions, we are able to
resolve the spreading, collimation, and edge effects of the blast wave as it
encounters the change in circumburst medium. In all cases considered in
this paper, we find that a flare will not be observed for any of the density
changes studied.
Original languageEnglish
Publication statusPublished - 1 Aug 2013
Event7th Huntsville Gamma-Ray Burst Symposium, GRB 2013 - Nashville, Tennessee, USA United States
Duration: 14 Apr 201318 Apr 2013

Other

Other7th Huntsville Gamma-Ray Burst Symposium, GRB 2013
CountryUSA United States
CityTennessee
Period14/04/1318/04/13

Keywords

  • Astrophysics - High Energy Astrophysical Phenomena

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  • Cite this

    Gat, I., van Eerten, H., & MacFadyen, A. (2013). GRB afterglow blast wave encountering sudden circumburst density change produces no flares. Paper presented at 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013, Tennessee, USA United States.