TablePSF¶

class gammapy.irf.TablePSF(rad, psf_value, interp_kwargs=None)[source]¶

Bases: object

Radially-symmetric table PSF.

Parameters

radQuantity with angle units: Offset wrt source position
psf_valueQuantity with sr^-1 units: PSF value array
interp_kwargsdict: Keyword arguments passed to ScaledRegularGridInterpolator

Methods Summary

`broaden`(self, factor[, normalize])	Broaden PSF by scaling the offset array.
`containment`(self, rad_max)	Compute PSF containment fraction.
`containment_radius`(self, fraction)	Containment radius.
`evaluate`(self, rad)	Evaluate PSF.
`from_shape`(shape, width, rad)	Make TablePSF objects with commonly used shapes.
`info`(self)	Print basic info.
`normalize`(self)	Normalize PSF to unit integral.
`plot_psf_vs_rad`(self[, ax])	Plot PSF vs radius.

Methods Documentation

broaden(self, factor, normalize=True)[source]¶

Broaden PSF by scaling the offset array.

For a broadening factor \(f\) and the offset array \(r\), the offset array scaled in the following way:

\[r_{new} = f \times r_{old} \frac{dP}{dr}(r_{new}) = \frac{dP}{dr}(r_{old})\]

Parameters

factorfloat: Broadening factor
normalizebool: Normalize PSF after broadening

containment(self, rad_max)[source]¶

Compute PSF containment fraction.

Parameters

rad_maxQuantity: Offset angle range

Returns

integralfloat: PSF integral

containment_radius(self, fraction)[source]¶

Containment radius.

Parameters

fractionarray_like: Containment fraction (range 0 .. 1)

Returns

radAngle: Containment radius angle

evaluate(self, rad)[source]¶

Evaluate PSF.

The following PSF quantities are available:

‘dp_domega’: PDF per 2-dim solid angle \(\Omega\) in sr^-1

\[\frac{dP}{d\Omega}\]

Parameters

radAngle: Offset wrt source position

Returns

psf_valueQuantity: PSF value

classmethod from_shape(shape, width, rad)[source]¶

Make TablePSF objects with commonly used shapes.

This function is mostly useful for examples and testing.

Parameters

shape{‘disk’, ‘gauss’}: PSF shape.
widthQuantity with angle units: PSF width angle (radius for disk, sigma for Gauss).
radQuantity with angle units: Offset angle

Returns

psfTablePSF: Table PSF

Examples

>>> import numpy as np
>>> from astropy.coordinates import Angle
>>> from gammapy.irf import TablePSF
>>> rad = Angle(np.linspace(0, 0.7, 100), 'deg')
>>> psf = TablePSF.from_shape(shape='gauss', width='0.2 deg', rad=rad)

info(self)[source]¶: Print basic info.

normalize(self)[source]¶

Normalize PSF to unit integral.

Computes the total PSF integral via the \(dP / dr\) spline and then divides the \(dP / dr\) array.

plot_psf_vs_rad(self, ax=None, **kwargs)[source]¶

Plot PSF vs radius.

Parameters

ax``
kwargsdict: Keyword arguments passed to matplotlib.pyplot.plot