combine_flux_maps

gammapy.estimators.utils.combine_flux_maps(maps, method='gaussian_errors', reference_model=None, dnde_scan_axis=None)

Create a FluxMaps by combining a list of flux maps with the same geometry.

This assumes the flux maps are independent measurements of the same true value. The GTI is stacked in the process.

Parameters:

mapslist of FluxMaps

List of maps with the same geometry.

methodstr

• gaussian_errors :

  Under the gaussian error approximation the likelihood is given by the gaussian distibution. The product of gaussians is also a gaussian so can derive dnde, dnde_err, and ts.

• distrib :

  Likelihood profile approximation assuming that probabilities distributions for flux points correspond to asymmetric gaussians and for upper limits to complementary error functions. Use available quantities among dnde, dnde_err, dnde_errp, dnde_errn, dnde_ul, and ts.

• profile :

  Sum the likelihood profile maps. The flux maps must contains the stat_scan maps.

Default is “gaussian_errors” which is the faster but least accurate solution, “distrib” will be more accurate if dnde_errp and dnde_errn are available, “profile” will be even more accurate if “stat_scan” is available.

reference_modelSkyModel, optional

Reference model to use for conversions. Default is None and is will use the reference_model of the first FluxMaps in the list.

dnde_scan_axisMapAxis

Map axis providing the dnde values used to compute the profile. Default is None and it will be derived from the first FluxMaps in the list. Used only if method is distrib or profile.

Returns:

flux_mapsFluxMaps

Joint flux map.

See also

get_combined_flux_maps

same method but using directly the flux maps from estimators