Fitting afterglows with multi-dimensional simulations

G. Ryan, H. van Eerten, A. MacFadyen

Research output: Contribution to conferencePaper

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We present preliminary data fit results of synthetic light curves computed from numerical afterglow blast wave simulations. Our technique uses Markov chain Monte Carlo (MCMC) in a new data analysis tool, ScaleFit. Scaling relations in both the hydrodynamics and radiation equations allow light curves to be parameterized by a small set of scaleinvariant characteristic quantities. These quantities have been calculated and tabulated from high resolution two-dimensional hydrodynamic simulations. Producing a light curve from the characteristics takes only a millisecond, allowing for the use of MCMC data fitting techniques which can require millions of iterations. ScaleFit is a portable, lightweight, python package which performs this analysis on afterglow light curves. Using the set of Swift-XRT light curves from 2011 & 2012 with known redshifts, we find ScaleFit can measure the jet opening angle, observer angle, and spectral index of most afterglows. Globally we find gamma-ray burst afterglows tend to be observed off axis, at a significant fraction of the jet opening angle.
Original languageEnglish
Publication statusPublished - 1 Jul 2013
Event7th Huntsville Gamma-Ray Burst Symposium, GRB 2013 - Nashville, Tennessee, USA United States
Duration: 14 Apr 201318 Apr 2013


Other7th Huntsville Gamma-Ray Burst Symposium, GRB 2013
Country/TerritoryUSA United States


  • Astrophysics - High Energy Astrophysical Phenomena


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