PSFKing

class gammapy.irf.PSFKing(energy_lo, energy_hi, offset, gamma, sigma, energy_thresh_lo=<Quantity 0.1 TeV>, energy_thresh_hi=<Quantity 100. TeV>)

Bases: object

King profile analytical PSF depending on energy and offset.

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

Parameters:

energy_lo : Quantity

Lower energy boundary of the energy bin.

energy_hi : Quantity

Upper energy boundary of the energy bin.

offset : Angle

Offset nodes (1D)

gamma : ndarray

PSF parameter (2D)

sigma : Angle

PSF parameter (2D)

Methods Summary

evaluate([energy, offset])	Evaluate analytic PSF parameters at a given energy and offset.
evaluate_direct(r, gamma, sigma)	Evaluate the PSF model.
from_table(table)	Create PSFKing from Table.
info()	Print some basic info.
read(filename[, hdu])	Create PSFKing from FITS file.
to_energy_dependent_table_psf([theta, rad, …])	Convert to energy-dependent table PSF.
to_fits()	Convert PSF table data to FITS HDU list.
write(filename, *args, **kwargs)	Write PSF to FITS file.

Methods Documentation

evaluate(energy=None, offset=None)

Evaluate analytic PSF parameters at a given energy and offset.

Uses nearest-neighbor interpolation.

Parameters:

energy : Quantity

energy value

offset : Angle

Offset in the field of view

Returns:

values : Quantity

Interpolated value

static evaluate_direct(r, gamma, sigma)

Evaluate the PSF model.

Formula is given here: psf_king.

Parameters:

r : Angle

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

gamma : Quantity

model parameter, no unit

sigma : Angle

model parameter

Returns:

psf_value : Quantity

PSF value

classmethod from_table(table)

Create PSFKing from Table.

Parameters:

table : Table

Table King PSF info.

info()

Print some basic info.

classmethod read(filename, hdu=1)

Create PSFKing from FITS file.

Parameters:

filename : str

File name

to_energy_dependent_table_psf(theta=None, rad=None, exposure=None)

Convert to energy-dependent table PSF.

Parameters:

theta : Angle

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

rad : Angle

Offset from PSF center used for evaluating the PSF on a grid. Default offset = [0, 0.005, …, 1.495, 1.5] deg.

exposure : Quantity

Energy dependent exposure. Should be in units equivalent to ‘cm^2 s’. Default exposure = 1.

Returns:

table_psf : EnergyDependentTablePSF

Energy-dependent PSF

to_fits()

Convert PSF table data to FITS HDU list.

Returns:

hdu_list : HDUList

PSF in HDU list format.

write(filename, *args, **kwargs)

Write PSF to FITS file.

Calls writeto, forwarding all arguments.