Gamma-ray burst broadband afterglow modelling based on hydrodynamics simulations with BOXFIT
Gamma-ray bursts (GRBs) are cosmic explosions connected with the death of massive stars and are among the most
energetic and furthest events we currently observe in the Universe. These explosions are observed as second-to minute
long flashes of gamma-rays.
In the aftermath of a GRB, a long-lived (days to months) decaying source is visible at longer wavelengths,
from X-rays down to radio, is the result of the blast wave sweeping up the interstellar medium.
This source is called afterglow. The GRB group of the physics dept. has been collaborating with several
international groups actively involved in collecting and interpreting GRB broadband afterglow data.
Our group mainly collaborates and shares data with the GRB group of the
Astrophysics Research Institute of the Liverpool John Moores University (United Kingdom).
Recently, Van Eerten and collaborators developed a powerful tool for fitting such data sets,
which can be used to constrain the GRB explosion parameters through high-resolution
two-dimensional relativistic hydrodynamical (RHD) simulations.
This code is named BOXFIT and can be retrieved at the following website (see references below)
and the details are reported in a devoted refereed paper (Van Eerten et al. 2012).
The dynamics of the afterglow blast wave have been calculated in a series of 19
high-resolution two-dimensional simulations performed with a specific RHD code.
The results of these calculations have been compressed and stored in a
series of 'box' data files and BOXFIT calculates the fluid state for arbitrary fluid variables
using interpolations between the data files and analytical scaling relations.
End-users of BOXFIT do not need to perform RHD simulations themselves.
It can be used both in parallel and on a single core, but the specific task of data fitting
requires the parallel configuration.
We have succesfully compiled and run the code under a linux machine running gcc v.4.4.4 both
32 and 64 bit.
Published paper:
- New constraints on gamma-ray burst jet geometry and relativistic shock physics
MNRAS (February 11, 2014) 438 (1): 752-767. doi: 10.1093/mnras/stt224
References
- Van Eerten et al., 2012, The Astrophysical Journal, 794, 44
- http://cosmo.nyu.edu/afterglowlibrary
Project cooperators
- Dott. Cristiano Guidorzi (principal investigator), Physics Department, University of Ferrara.