Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gamma-ray burst afterglow broadband fitting based directly on
  hydrodynamics simulations   We present a powerful new tool for fitting broadband gamma-ray burst
afterglow data, which can be used to determine the burst explosion parameters
and the synchrotron radiation parameters. By making use of scale invariance
between relativistic jets of different energies and different circumburst
medium densities, and by capturing the output of high-resolution
two-dimensional relativistic hydrodynamical (RHD) jet simulations in a concise
summary, the jet dynamics are generated quickly. Our method calculates the full
light curves and spectra using linear radiative transfer sufficiently fast to
allow for a direct iterative fit of RHD simulations to the data. The fit
properly accounts for jet features that so far have not been successfully
modeled analytically, such as jet decollimation, inhomogeneity along the shock
front and the transitory phase between the early time relativistic and late
time non-relativistic outflow. As a first application of the model we
simultaneously fit the radio, X-ray and optical data of GRB 990510. We not only
find noticeable differences between our findings for the explosion and
radiation parameters and those of earlier authors, but also an improved model
fit when we include the observer angle in the data fit. The fit method will be
made freely available on request and on-line at
http://cosmo.nyu.edu/afterglowlibrary. In addition to data fitting, the
software tools can also be used to quickly generate a light curve or spectrum
for arbitrary observer position, jet and radiation parameters.

8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat