PSFKing

class gammapy.irf.PSFKing(axes, data=0, unit='', meta=None, interp_kwargs=None)

Bases: gammapy.irf.psf.parametric.ParametricPSF

King profile analytical PSF depending on energy and offset.

This PSF parametrisation and FITS data format is described here: PSF_KING.

Parameters

axeslist of MapAxis or MapAxes

Data axes, required are [“energy_true”, “offset”]

metadict

Meta data

Attributes Summary

axes	MapAxes
data
default_interp_kwargs
is_offset_dependent	Whether the IRF depends on offset
is_pointlike	Whether the IRF is pointlike of full containment.
quantity	Quantity
required_axes
required_parameters
tag
unit	Map unit (Unit)

Methods Summary

containment(rad, **kwargs)	Containment of the PSF at given axes coordinates
containment_radius(fraction[, factor])	Containment radius at given axes coordinates
cumsum(axis_name)	Compute cumsum along a given axis
evaluate(rad, **kwargs)	Evaluate the PSF model.
evaluate_containment(rad, gamma, sigma)	Containment of the PSF at given axes coordinates
evaluate_direct(rad, gamma, sigma)	Evaluate the PSF model.
evaluate_parameters(energy_true, offset)	Evaluate analytic PSF parameters at a given energy and offset.
from_hdulist(hdulist[, hdu, format])	Create from HDUList.
from_table(table[, format])	Create parametric psf from Table.
info([fraction, energy_true, offset])	Print PSF summary info.
integral(axis_name, **kwargs)	Compute integral along a given axis
integrate_log_log(axis_name, **kwargs)	Integrate along a given axis.
interp_missing_data(axis_name)	Interpolate missing data along a given axis
normalize()	Normalize parametric PSF
pad(pad_width, axis_name, **kwargs)	Pad irf along a given axis.
peek([figsize])	Quick-look summary plots.
plot_containment_radius([ax, fraction, add_cbar])	Plot containment image with energy and theta axes.
plot_containment_radius_vs_energy([ax, …])	Plot containment fraction as a function of energy.
plot_psf_vs_rad([ax, offset, energy_true])	Plot PSF vs rad.
read(filename[, hdu, format])	Read from file.
to_hdulist([format])
to_psf3d([rad])	Create a PSF3D from a parametric PSF.
to_table([format])	Convert PSF table data to table.
to_table_hdu([format])	Convert to BinTableHDU.
write(filename, *args, **kwargs)	Write IRF to fits.

Attributes Documentation

axes

MapAxes

data

default_interp_kwargs = {'bounds_error': False, 'fill_value': None}

is_offset_dependent

Whether the IRF depends on offset

is_pointlike

Whether the IRF is pointlike of full containment.

quantity

Quantity

required_axes = ['energy_true', 'offset']

required_parameters = ['gamma', 'sigma']

tag = 'psf_king'

unit

Map unit (Unit)

Methods Documentation

containment(rad, **kwargs)

Containment of the PSF at given axes coordinates

Parameters

radQuantity

Rad value

**kwargsdict

Other coordinates

Returns

containmentndarray

Containment

containment_radius(fraction, factor=20, **kwargs)

Containment radius at given axes coordinates

Parameters

fractionfloat or ndarray

Containment fraction

factorint

Up-sampling factor of the rad axis, determines the precision of the computed containment radius.

**kwargsdict

Other coordinates

Returns

radiusAngle

Containment radius

cumsum(axis_name)

Compute cumsum along a given axis

Parameters

axis_namestr

Along which axis to integrate.

Returns

irfIRF

Cumsum IRF

evaluate(rad, **kwargs)

Evaluate the PSF model.

Parameters

radAngle

Offset from PSF center used for evaluating the PSF on a grid

**kwargsdict

Other coordinates

Returns

psf_valueQuantity

PSF value

static evaluate_containment(rad, gamma, sigma)

Containment of the PSF at given axes coordinates

Parameters

radQuantity

Rad value

gammaQuantity

Gamma parameter

sigmaQuantity

Sigma parameter

Returns

containmentndarray

Containment

static evaluate_direct(rad, gamma, sigma)

Evaluate the PSF model.

Formula is given here: PSF_KING.

Parameters

radAngle

Offset from PSF center used for evaluating the PSF on a grid

Returns

psf_valueQuantity

PSF value

evaluate_parameters(energy_true, offset)

Evaluate analytic PSF parameters at a given energy and offset.

Uses nearest-neighbor interpolation.

Parameters

energy_trueQuantity

energy value

offsetAngle

Offset in the field of view

Returns

valuesQuantity

Interpolated value

classmethod from_hdulist(hdulist, hdu=None, format='gadf-dl3')

Create from HDUList.

Parameters

hdulistHDUList

HDU list

hdustr

HDU name

format{“gadf-dl3”}

Format specification

Returns

irfIRF

IRF class

classmethod from_table(table, format='gadf-dl3')

Create parametric psf from Table.

Parameters

tableTable

Table info.

Returns

psfParametricPSF

PSF class

info(fraction=(0.68, 0.95), energy_true=<Quantity [[ 1.], [10.]] TeV>, offset=<Quantity 0. deg>)

Print PSF summary info.

The containment radius for given fraction, energies and thetas is computed and printed on the command line.

Parameters

fractionlist

Containment fraction to compute containment radius for.

energy_trueQuantity

Energies to compute containment radius for.

offsetQuantity

Offset to compute containment radius for.

Returns

ssstring

Formatted string containing the summary info.

integral(axis_name, **kwargs)

Compute integral along a given axis

This method uses interpolation of the cumulative sum.

Parameters

axis_namestr

Along which axis to integrate.

**kwargsdict

Coordinates at which to evaluate the IRF

Returns

arrayQuantity

Returns 2D array with axes offset

integrate_log_log(axis_name, **kwargs)

Integrate along a given axis.

This method uses log-log trapezoidal integration.

Parameters

axis_namestr

Along which axis to integrate.

**kwargsdict

Coordinates at which to evaluate the IRF

Returns

arrayQuantity

Returns 2D array with axes offset

interp_missing_data(axis_name)

Interpolate missing data along a given axis

normalize()

Normalize parametric PSF

pad(pad_width, axis_name, **kwargs)

Pad irf along a given axis.

Parameters

pad_width{sequence, array_like, int}

Number of pixels padded to the edges of each axis.

axis_namestr

Which axis to downsample. By default spatial axes are padded.

**kwargsdict

Keyword argument forwarded to pad

Returns

irfIRF

Padded irf

peek(figsize=(15, 5))

Quick-look summary plots.

plot_containment_radius(ax=None, fraction=0.68, add_cbar=True, **kwargs)

Plot containment image with energy and theta axes.

Parameters

axAxes

Axes to plot on.

fractionfloat

Containment fraction between 0 and 1.

add_cbarbool

Add a colorbar

**kwargsdict

Keyword arguments passed to pcolormesh

Returns

axAxes

Axes to plot on.

plot_containment_radius_vs_energy(ax=None, fraction=(0.68, 0.95), offset=<Quantity [0., 1.] deg>, **kwargs)

Plot containment fraction as a function of energy.

Parameters

axAxes

Axes to plot on.

fractionlist of float or ndarray

Containment fraction between 0 and 1.

offsetQuantity

Offset array

**kwargsdict

Keyword arguments passed to plot

Returns

axAxes

Axes to plot on.

plot_psf_vs_rad(ax=None, offset=<Quantity [0.] deg>, energy_true=<Quantity [ 0.1, 1., 10. ] TeV>, **kwargs)

Plot PSF vs rad.

Parameters

axAxes

Axes to plot on.

offsetAngle

Offset in the field of view. Default offset = 0 deg

energy_trueQuantity

True energy at which to plot the profile

classmethod read(filename, hdu=None, format='gadf-dl3')

Read from file.

Parameters

filenamestr or Path

Filename

hdustr

HDU name

format{“gadf-dl3”}

Format specification

Returns

irfIRF

IRF class

to_hdulist(format='gadf-dl3')

to_psf3d(rad=None)

Create a PSF3D from a parametric PSF.

It will be defined on the same energy and offset values than the input psf.

Parameters

radQuantity

Rad values

Returns

psf3dPSF3D

PSF3D.

to_table(format='gadf-dl3')

Convert PSF table data to table.

Parameters

format{“gadf-dl3”}

Format specification

Returns

hdu_listHDUList

PSF in HDU list format.

to_table_hdu(format='gadf-dl3')

Convert to BinTableHDU.

Parameters

format{“gadf-dl3”}

Format specification

Returns

hduBinTableHDU

IRF data table hdu

write(filename, *args, **kwargs)

Write IRF to fits.

Calls writeto, forwarding all arguments.