EnergyDependentTablePSF

class gammapy.irf.EnergyDependentTablePSF(energy, rad, exposure=None, psf_value=None, interp_kwargs=None)

Bases: object

Energy-dependent radially-symmetric table PSF (gtpsf format).

TODO: add references and explanations.

Parameters:

energy : Quantity

Energy (1-dim)

rad : Quantity with angle units

Offset angle wrt source position (1-dim)

exposure : Quantity

Exposure (1-dim)

psf_value : Quantity

PSF (2-dim with axes: psf[energy_index, offset_index]

interp_kwargs : dict

Interpolation keyword arguments pass to ScaledRegularGridInterpolator.

Methods Summary

containment(self, energy, rad_max)	Compute containment of the PSF.
containment_radius(self, energy[, fraction])	Containment radius.
evaluate(self[, energy, rad, method])	Evaluate the PSF at a given energy and offset
from_fits(hdu_list)	Create EnergyDependentTablePSF from gtpsf format HDU list.
info(self)	Print basic info
plot_containment_vs_energy(self[, ax, fractions])	Plot containment versus energy.
plot_exposure_vs_energy(self)	Plot exposure versus energy.
plot_psf_vs_rad(self[, energies, ax])	Plot PSF vs radius.
read(filename)	Create EnergyDependentTablePSF from gtpsf-format FITS file.
stack(self, psf)	Stack two EnergyDependentTablePSF objects.s
table_psf_at_energy(self, energy[, method])	Create TablePSF at one given energy.
table_psf_in_energy_band(self, energy_band)	Average PSF in a given energy band.
to_fits(self)	Convert to FITS HDU list format.
write(self, \*args, \*\*kwargs)	Write to FITS file.

Methods Documentation

containment(self, energy, rad_max)

Compute containment of the PSF.

Parameters:

energy : Quantity

Energy

rad_max : Angle

Maximum offset angle.

Returns:

fraction : array_like

Containment fraction (in range 0 .. 1)

containment_radius(self, energy, fraction=0.68)

Containment radius.

Parameters:

energy : Quantity

Energy

fraction : float

Containment fraction.

Returns:

rad : Quantity

Containment radius in deg

evaluate(self, energy=None, rad=None, method='linear')

Evaluate the PSF at a given energy and offset

Parameters:

energy : Quantity

Energy value

rad : Angle

Offset wrt source position

method : {“linear”, “nearest”}

Linear or nearest neighbour interpolation.

Returns:

values : Quantity

Interpolated value

classmethod from_fits(hdu_list)

Create EnergyDependentTablePSF from gtpsf format HDU list.

Parameters:

hdu_list : HDUList

HDU list with THETA and PSF extensions.

info(self)

Print basic info

plot_containment_vs_energy(self, ax=None, fractions=[0.68, 0.8, 0.95], **kwargs)

Plot containment versus energy.

plot_exposure_vs_energy(self)

Plot exposure versus energy.

plot_psf_vs_rad(self, energies=None, ax=None, **kwargs)

Plot PSF vs radius.

Parameters:

energy : Quantity

Energies where to plot the PSF.

**kwargs : dict

Keyword arguments pass to plot.

classmethod read(filename)

Create EnergyDependentTablePSF from gtpsf-format FITS file.

Parameters:

filename : str

File name

stack(self, psf)

Stack two EnergyDependentTablePSF objects.s

Parameters:

psf : EnergyDependentTablePSF

PSF to stack.

Returns:

stacked_psf : EnergyDependentTablePSF

Stacked PSF.

table_psf_at_energy(self, energy, method='linear', **kwargs)

Create TablePSF at one given energy.

Parameters:

energy : Quantity

Energy

method : {“linear”, “nearest”}

Linear or nearest neighbour interpolation.

Returns:

psf : TablePSF

Table PSF

table_psf_in_energy_band(self, energy_band, spectrum=None, n_bins=11, **kwargs)

Average PSF in a given energy band.

Expected counts in sub energy bands given the given exposure and spectrum are used as weights.

Parameters:

energy_band : Quantity

Energy band

spectrum : SpectralModel

Spectral model used for weighting the PSF. Default is a power law with index=2.

n_bins : int

Number of energy points in the energy band, used to compute the weigthed PSF.

Returns:

psf : TablePSF

Table PSF

to_fits(self)

Convert to FITS HDU list format.

Returns:

hdu_list : HDUList

PSF in HDU list format.

write(self, *args, **kwargs)

Write to FITS file.

Calls writeto, forwarding all arguments.