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IRFStacker

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

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

Methods Documentation

stack_aeff()

Compute mean effective area (EffectiveAreaTable).

stack_edisp()

Compute mean energy dispersion (EnergyDispersion).