FermiLATBasicImageEstimator

class gammapy.image.FermiLATBasicImageEstimator(reference, emin, emax, spectral_model=None)

Bases: gammapy.image.basic.BasicImageEstimator

Estimate basic sky images for Fermi-LAT data.

Can compute the following images: counts, exposure, background

TODO: allow different background estimation methods TODO: add examples

Parameters:

reference : SkyImage

Reference sky image.

emin : Quantity

Lower bound of energy range.

emax : Quantity

Upper bound of energy range.

spectral_model : SpectralModel

Spectral model assumption to compute mean exposure and psf images.

Examples

This example shows how to compute a set of basic images for the galactic center region using a prepared 2FHL dataset:

from astropy import unit as u
from gammapy.image import SkyImage, FermiLATBasicImageEstimator
from gammapy.datasets import FermiLATDataset

kwargs = {}
kwargs['reference'] = SkyImage.empty(nxpix=201, nypix=101, binsz=0.05)
kwargs['emin'] = 50 * u.GeV
kwargs['emax'] = 3000 * u.GeV
image_estimator = FermiLATBasicImageEstimator(**kwargs)

filename = '$FERMI_LAT_DATA/2fhl/fermi_2fhl_data_config.yaml'
dataset = FermiLATDataset(filename)

result = image_estimator.run(dataset)
result['counts'].show()

Methods Summary

background(dataset)	Estimate predicted counts background image in energy band.
counts(dataset)	Estimate counts image in energy band.
exposure(dataset)	Estimate a spectral model weighted exposure image from an exposure cube.
run(dataset[, which])	Estimate sky images.

Methods Documentation

background(dataset)

Estimate predicted counts background image in energy band.

The background estimate is based on the Fermi-LAT galactic and isotropic diffuse models.

Parameters:

dataset : FermiLATDataset

Fermi basic dataset to compute images for.

Returns:

background : SkyImage

Predicted number of background counts sky image.

counts(dataset)

Estimate counts image in energy band.

Parameters:

dataset : FermiLATDataset

Fermi basic dataset to compute images for.

Returns:

counts : SkyImage

Counts sky image.

exposure(dataset)

Estimate a spectral model weighted exposure image from an exposure cube.

Parameters:

dataset : FermiLATDataset

Fermi basic dataset to compute images for.

Returns:

exposure : SkyImage

Exposure sky image.

run(dataset, which='all')

Estimate sky images.

Parameters:

dataset : FermiLATDataset

Fermi basic dataset to compute images for.

which : str or list of str

Which images to compute. Can be:

• ‘all’
• ‘counts’
• ‘background’
• ‘exposure’
• ‘excess’
• ‘flux’
• ‘psf’

Or a list containing any subset of the images listed above.

Returns:

images : SkyImageList

List of sky images.