SpectrumExtraction

class gammapy.spectrum.SpectrumExtraction(obs_list, bkg_estimate, e_reco=None, e_true=None, containment_correction=False, max_alpha=1)[source]

Bases: object

Creating input data to 1D spectrum fitting

This class is responsible for extracting a SpectrumObservation from a DataStoreObservation. The background estimation is done beforehand, using e.g. the ReflectedRegionsBackgroundEstimator. For point sources analyzed with ‘full containment’ IRFs, a correction for PSF leakage out of the circular ON region can be applied. For more info see Spectral Fitting. For a usage example see spectrum_analysis.ipynb

Parameters:

obs_list : ObservationList

Observations to process

bkg_estimate : BackgroundEstimate

Background estimate, e.g. of ReflectedRegionsBackgroundEstimator

e_reco : Quantity, optional

Reconstructed energy binning

e_true : Quantity, optional

True energy binning

containment_correction : bool

Apply containment correction for point sources and circular on regions.

max_alpha : float

Maximum alpha value to accept, if the background was estimated using reflected regions this is 1 / minimum number of regions.

Attributes Summary

DEFAULT_RECO_ENERGY Reconstruced energy axis to be used if not specified otherwise
DEFAULT_TRUE_ENERGY True energy axis to be used if not specified otherwise

Methods Summary

apply_containment_correction(obs, bkg) Apply containment correction
define_energy_threshold([method_lo_threshold]) Set energy threshold
extract_counts(bkg) Fill on and off vector for one observation
extract_irfs(obs) Extract IRFs
make_empty_vectors(obs, bkg) Create empty vectors
process(obs, bkg) Process one observation
run([outdir, use_sherpa]) Run all steps
write(outdir[, ogipdir, use_sherpa]) Write results to disk

Attributes Documentation

DEFAULT_RECO_ENERGY = <Quantity [ 1.00000000e-02, 1.13646367e-02, 1.29154967e-02, 1.46779927e-02, 1.66810054e-02, 1.89573565e-02, 2.15443469e-02, 2.44843675e-02, 2.78255940e-02, 3.16227766e-02, 3.59381366e-02, 4.08423865e-02, 4.64158883e-02, 5.27499706e-02, 5.99484250e-02, 6.81292069e-02, 7.74263683e-02, 8.79922544e-02, 1.00000000e-01, 1.13646367e-01, 1.29154967e-01, 1.46779927e-01, 1.66810054e-01, 1.89573565e-01, 2.15443469e-01, 2.44843675e-01, 2.78255940e-01, 3.16227766e-01, 3.59381366e-01, 4.08423865e-01, 4.64158883e-01, 5.27499706e-01, 5.99484250e-01, 6.81292069e-01, 7.74263683e-01, 8.79922544e-01, 1.00000000e+00, 1.13646367e+00, 1.29154967e+00, 1.46779927e+00, 1.66810054e+00, 1.89573565e+00, 2.15443469e+00, 2.44843675e+00, 2.78255940e+00, 3.16227766e+00, 3.59381366e+00, 4.08423865e+00, 4.64158883e+00, 5.27499706e+00, 5.99484250e+00, 6.81292069e+00, 7.74263683e+00, 8.79922544e+00, 1.00000000e+01, 1.13646367e+01, 1.29154967e+01, 1.46779927e+01, 1.66810054e+01, 1.89573565e+01, 2.15443469e+01, 2.44843675e+01, 2.78255940e+01, 3.16227766e+01, 3.59381366e+01, 4.08423865e+01, 4.64158883e+01, 5.27499706e+01, 5.99484250e+01, 6.81292069e+01, 7.74263683e+01, 8.79922544e+01, 1.00000000e+02] TeV>

Reconstruced energy axis to be used if not specified otherwise

DEFAULT_TRUE_ENERGY = <Quantity [ 1.00000000e-02, 1.10069417e-02, 1.21152766e-02, 1.33352143e-02, 1.46779927e-02, 1.61559810e-02, 1.77827941e-02, 1.95734178e-02, 2.15443469e-02, 2.37137371e-02, 2.61015722e-02, 2.87298483e-02, 3.16227766e-02, 3.48070059e-02, 3.83118685e-02, 4.21696503e-02, 4.64158883e-02, 5.10896977e-02, 5.62341325e-02, 6.18965819e-02, 6.81292069e-02, 7.49894209e-02, 8.25404185e-02, 9.08517576e-02, 1.00000000e-01, 1.10069417e-01, 1.21152766e-01, 1.33352143e-01, 1.46779927e-01, 1.61559810e-01, 1.77827941e-01, 1.95734178e-01, 2.15443469e-01, 2.37137371e-01, 2.61015722e-01, 2.87298483e-01, 3.16227766e-01, 3.48070059e-01, 3.83118685e-01, 4.21696503e-01, 4.64158883e-01, 5.10896977e-01, 5.62341325e-01, 6.18965819e-01, 6.81292069e-01, 7.49894209e-01, 8.25404185e-01, 9.08517576e-01, 1.00000000e+00, 1.10069417e+00, 1.21152766e+00, 1.33352143e+00, 1.46779927e+00, 1.61559810e+00, 1.77827941e+00, 1.95734178e+00, 2.15443469e+00, 2.37137371e+00, 2.61015722e+00, 2.87298483e+00, 3.16227766e+00, 3.48070059e+00, 3.83118685e+00, 4.21696503e+00, 4.64158883e+00, 5.10896977e+00, 5.62341325e+00, 6.18965819e+00, 6.81292069e+00, 7.49894209e+00, 8.25404185e+00, 9.08517576e+00, 1.00000000e+01, 1.10069417e+01, 1.21152766e+01, 1.33352143e+01, 1.46779927e+01, 1.61559810e+01, 1.77827941e+01, 1.95734178e+01, 2.15443469e+01, 2.37137371e+01, 2.61015722e+01, 2.87298483e+01, 3.16227766e+01, 3.48070059e+01, 3.83118685e+01, 4.21696503e+01, 4.64158883e+01, 5.10896977e+01, 5.62341325e+01, 6.18965819e+01, 6.81292069e+01, 7.49894209e+01, 8.25404185e+01, 9.08517576e+01, 1.00000000e+02, 1.10069417e+02, 1.21152766e+02, 1.33352143e+02, 1.46779927e+02, 1.61559810e+02, 1.77827941e+02, 1.95734178e+02, 2.15443469e+02, 2.37137371e+02, 2.61015722e+02, 2.87298483e+02, 3.16227766e+02] TeV>

True energy axis to be used if not specified otherwise

Methods Documentation

apply_containment_correction(obs, bkg)[source]

Apply containment correction

Parameters:

obs : DataStoreObservation

observation

bkg : BackgroundEstimate

background esimate
define_energy_threshold(method_lo_threshold='area_max', **kwargs)[source]

Set energy threshold

Set the high and low energy threshold for each observation based on a chosen method.

Available methods for setting the low energy threshold

  • area_max : Set energy threshold at x percent of the maximum effective area (x given as kwargs[‘percent’])

Available methods for setting the high energy threshold

  • TBD
Parameters:

method_lo_threshold : {‘area_max’}

method for defining the low energy threshold
extract_counts(bkg)[source]

Fill on and off vector for one observation

Parameters:

bkg : BackgroundEstimate

background esimate
extract_irfs(obs)[source]

Extract IRFs

Parameters:

obs : DataStoreObservation

observation
make_empty_vectors(obs, bkg)[source]

Create empty vectors

This method copies over all meta info and sets up the energy binning

Parameters:

obs : DataStoreObservation

observation

bkg : BackgroundEstimate

background esimate
process(obs, bkg)[source]

Process one observation

run(outdir=None, use_sherpa=False)[source]

Run all steps

Parameters:

outdir : Path, str

directory to write results files to (if given)

use_sherpa : bool, optional

Write Sherpa compliant files, default: False
write(outdir, ogipdir='ogip_data', use_sherpa=False)[source]

Write results to disk

Parameters:

outdir : Path

Output folder

ogipdir : str, optional

Folder name for OGIP data, default: ‘ogip_data’

use_sherpa : bool, optional

Write Sherpa compliant files, default: False