# IRFStacker¶

class gammapy.irf.IRFStacker(list_aeff, list_livetime, list_edisp=None, list_low_threshold=None, list_high_threshold=None)[source]

Bases: object

Stack instrument response functions.

Compute mean effective area and the mean energy dispersion for a given for a given list of instrument response functions. Results are stored as attributes.

The stacking of $$j$$ elements is implemented as follows. $$k$$ and $$l$$ denote a bin in reconstructed and true energy, respectively.

\begin{align}\begin{aligned}\begin{split}\epsilon_{jk} =\left\{\begin{array}{cl} 1, & \mbox{if bin k is inside the energy thresholds}\\ 0, & \mbox{otherwise} \end{array}\right.\end{split}\\\overline{t} = \sum_{j} t_i\\\overline{\mathrm{aeff}}_l = \frac{\sum_{j}\mathrm{aeff}_{jl} \cdot t_j}{\overline{t}}\\\overline{\mathrm{edisp}}_{kl} = \frac{\sum_{j} \mathrm{edisp}_{jkl} \cdot \mathrm{aeff}_{jl} \cdot t_j \cdot \epsilon_{jk}}{\sum_{j} \mathrm{aeff}_{jl} \cdot t_j}\end{aligned}\end{align}
Parameters: list_aeff : list list of EffectiveAreaTable list_livetime : list list of Quantity (livetime) list_edisp : list list of EnergyDispersion list_low_threshold : list list of low energy threshold, optional for effective area mean computation list_high_threshold : list list of high energy threshold, optional for effective area mean computation

Methods Summary

 stack_aeff(self) Compute mean effective area (EffectiveAreaTable). stack_edisp(self) Compute mean energy dispersion (EnergyDispersion).

Methods Documentation

stack_aeff(self)[source]

Compute mean effective area (EffectiveAreaTable).

stack_edisp(self)[source]

Compute mean energy dispersion (EnergyDispersion).