SpectrumEnergyGroupMaker

class gammapy.spectrum.SpectrumEnergyGroupMaker(obs)

Bases: object

Energy bin groups for spectral analysis.

This class contains both methods that run algorithms that compute groupings as well as the results as data members and methods to debug and assess the results.

The input obs is used read-only, to access the counts energy binning, as well as some other info that is used for energy bin grouping.

This class creates the groups attribute on construction, with exactly one group per energy bin. It is then modified by calling methods on this class, usually to declare some bins as under- and overflow (i.e. not to be used in spectral analysis), and to group bins (e.g. for flux point computation).

See Spectrum energy grouping for examples.

Parameters:

obs : SpectrumObservation

Spectrum observation

See also

SpectrumEnergyGroups, SpectrumEnergyGroup, FluxPointEstimator

Attributes

obs	(SpectrumObservation) Spectrum observation data
groups	(SpectrumEnergyGroups) List of energy groups

Methods Summary

compute_groups_adaptive(min_signif[, …])	Compute energy binning for flux points.
compute_groups_fixed(ebounds)	Apply grouping for a given fixed energy binning.
compute_range_safe()	Apply safe energy range of observation to groups.

Methods Documentation

compute_groups_adaptive(min_signif, rebin_factor=2)

Compute energy binning for flux points.

This is useful to get an energy binning to use with FluxPoints() Each bin in the resulting energy binning will include a min_signif source detection.

TODO: It is required that at least two fine bins be included in one flux point interval, otherwise the sherpa covariance method breaks down.

Parameters:

min_signif : float

Required significance for each bin

compute_groups_fixed(ebounds)

Apply grouping for a given fixed energy binning.

Parameters:

ebounds : Quantity

Energy bounds array

compute_range_safe()

Apply safe energy range of observation to groups.

This method takes the safe energy range information from self.obs and changes self.groups like this:

• group bins below the safe energy range into one group of type “underflow”
• group bins above the safe energy range into one group of type “overflow”