{{lastupdated_at}} by {{lastupdated_by}}

{{>toc}}

h1. GModelSpectralExpPlaw

h2. Validation

The model has been validation by generating pull distributions using @cspull@. The validation has been done using ctools-00-06-00 and GammaLib-00-07-00.

An exponentially cut-off power law following the HESS Crab spectrum was used to generate mock data. Below the pull distributions for all fitted parameters (prefactor, spectral index, cut off energy and 2 background parameters) are shown for 10000 Monte Carlo samples for an exposure time of 18000 seconds. The deadtime correction factor was assumed to 0.95. The file @kb_E_50h_v3@ was used for the instrumental response function, data have been simulated for 0.1-100 TeV for an ROI of 5 deg.

| !t18000_n10000_pre.png! | !t18000_n10000_index.png! | !t18000_n10000_cutoff.png! |
| !t18000_n10000_bkg_norm.png! | !t18000_n10000_bkg_sigma.png! | |

Apparently, there is some asymmetry in the uncertainty of the cut off energy. I guess that this comes from the fact that the cut off energy enters under the exponential in the spectral model, making the uncertainty inherently asymmetric.

Note: we may explore a model where instead of fitting the cut off energy, one fits the exponential of the cut off energy as parameter.