EffectiveAreaTable2D¶

class gammapy.irf.EffectiveAreaTable2D(axes, data=0, unit='', meta=None, interp_kwargs=None)[source]¶

Bases: gammapy.irf.core.IRF

2D effective area table.

Data format specification: AEFF_2D

Parameters

energy_axis_trueMapAxis: True energy axis
offset_axisMapAxis: Field of view offset axis.
dataQuantity: Effective area
metadict: Meta data

Examples

Here’s an example you can use to learn about this class:

>>> from gammapy.irf import EffectiveAreaTable2D
>>> filename = '$GAMMAPY_DATA/cta-1dc/caldb/data/cta/1dc/bcf/South_z20_50h/irf_file.fits'
>>> aeff = EffectiveAreaTable2D.read(filename, hdu='EFFECTIVE AREA')
>>> print(aeff)
EffectiveAreaTable2D
--------------------

  axes  : ['energy_true', 'offset']
  shape : (42, 6)
  ndim  : 2
  unit  : m2
  dtype : >f4

Here’s another one, created from scratch, without reading a file:

>>> from gammapy.irf import EffectiveAreaTable2D
>>> from gammapy.maps import MapAxis
>>> energy_axis_true = MapAxis.from_energy_bounds("0.1 TeV", "100 TeV", nbin=30, name="energy_true")
>>> offset_axis = MapAxis.from_bounds(0, 5, nbin=4, name="offset")
>>> aeff = EffectiveAreaTable2D(axes=[energy_axis_true, offset_axis], data=1e10, unit="cm2")
>>> print(aeff)
EffectiveAreaTable2D
--------------------

  axes  : ['energy_true', 'offset']
  shape : (30, 4)
  ndim  : 2
  unit  : cm2
  dtype : float64

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`
`tag`
`unit`	Map unit (`Unit`)

Methods Summary

`cumsum`(axis_name)	Compute cumsum along a given axis
`evaluate`([method])	Evaluate IRF
`from_hdulist`(hdulist[, hdu, format])	Create from `HDUList`.
`from_parametrization`([energy_axis_true, …])	Create parametrized effective area.
`from_table`(table[, format])	Read from `Table`.
`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`(axis_name)	Normalise data in place along a given axis.
`pad`(pad_width, axis_name, **kwargs)	Pad irf along a given axis.
`peek`([figsize])	Quick-look summary plots.
`plot`([ax, add_cbar])	Plot effective area image.
`plot_energy_dependence`([ax, offset])	Plot effective area versus energy for a given offset.
`plot_offset_dependence`([ax, energy])	Plot effective area versus offset for a given energy.
`read`(filename[, hdu, format])	Read from file.
`to_hdulist`([format])
`to_table`([format])	Convert 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': 0.0}¶

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']¶

tag = 'aeff_2d'¶

unit¶: Map unit (Unit)

Methods Documentation

cumsum(axis_name)¶

Compute cumsum along a given axis

Parameters

axis_namestr: Along which axis to integrate.

Returns

irfIRF: Cumsum IRF

evaluate(method=None, **kwargs)¶

Evaluate IRF

Parameters

**kwargsdict: Coordinates at which to evaluate the IRF
methodstr {‘linear’, ‘nearest’}, optional: Interpolation method

Returns

arrayQuantity: Interpolated values

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_parametrization(energy_axis_true=None, instrument='HESS')[source]¶

Create parametrized effective area.

Parametrizations of the effective areas of different Cherenkov telescopes taken from Appendix B of Abramowski et al. (2010), see https://ui.adsabs.harvard.edu/abs/2010MNRAS.402.1342A .

\[A_{eff}(E) = g_1 \left(\frac{E}{\mathrm{MeV}}\right)^{-g_2}\exp{\left(-\frac{g_3}{E}\right)}\]

This method does not model the offset dependence of the effective area, but just assumes that it is constant.

Parameters

energy_axis_trueMapAxis: Energy binning, analytic function is evaluated at log centers
instrument{‘HESS’, ‘HESS2’, ‘CTA’}: Instrument name

Returns

aeffEffectiveAreaTable2D: Effective area table

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

Read from Table.

Parameters

tableTable: Table with irf data
format{“gadf-dl3”}: Format specification

Returns

irfIRF: IRF class.

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(axis_name)¶

Normalise data in place along a given axis.

Parameters

axis_namestr: Along which axis to normalize.

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))[source]¶: Quick-look summary plots.

plot(ax=None, add_cbar=True, **kwargs)[source]¶: Plot effective area image.

plot_energy_dependence(ax=None, offset=None, **kwargs)[source]¶

Plot effective area versus energy for a given offset.

Parameters

axAxes, optional: Axis
offsetAngle: Offset
kwargsdict: Forwarded tp plt.plot()

Returns

axAxes: Axis

plot_offset_dependence(ax=None, energy=None, **kwargs)[source]¶

Plot effective area versus offset for a given energy.

Parameters

axAxes, optional: Axis
energyQuantity: Energy
**kwargsdict: Keyword argument passed to plot

Returns

axAxes: Axis

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_table(format='gadf-dl3')¶

Convert to table

Parameters

format{“gadf-dl3”}: Format specification

Returns

tableTable: IRF data table

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.