FluxMaps#

class gammapy.estimators.FluxMaps(data, reference_model, meta=None, gti=None, filter_success_nan=True)[source]#

Bases: object

A flux map / points container.

It contains a set of Map objects that store the estimated flux as a function of energy as well as associated quantities (typically errors, upper limits, delta TS and possibly raw quantities such counts, excesses etc). It also contains a reference model to convert the flux values in different formats. Usually, this should be the model used to produce the flux map.

The associated map geometry can use a RegionGeom to store the equivalent of flux points, or a WcsGeom/HpxGeom to store an energy dependent flux map.

The container relies internally on the ‘Likelihood’ SED type defined in SED and offers convenience properties to convert to other flux formats, namely: dnde, flux, eflux or e2dnde. The conversion is done according to the reference model spectral shape.

Parameters
datadict of Map

the maps dictionary. Expected entries are the following: * norm : the norm factor * norm_err : optional, the error on the norm factor. * norm_errn : optional, the negative error on the norm factor. * norm_errp : optional, the positive error on the norm factor. * norm_ul : optional, the upper limit on the norm factor. * norm_scan : optional, the norm values of the test statistic scan. * stat_scan : optional, the test statistic scan values. * ts : optional, the delta TS associated with the flux value. * sqrt_ts : optional, the square root of the TS, when relevant. * success : optional, a boolean tagging the validity of the estimation

reference_modelSkyModel, optional

The reference model to use for conversions. If None, a model consisting of a point source with a power law spectrum of index 2 is assumed.

metadict, optional

Dict of metadata.

gtiGTI, optional

Maps GTI information.

filter_success_nanboolean, optional

Set fitted norm and error to NaN when the fit has not succeeded.

Attributes Summary

available_quantities

Available quantities

counts

Predicted counts null hypothesis

dnde

Return differential flux (dnde) SED values.

dnde_err

Return differential flux (dnde) SED errors.

dnde_errn

Return differential flux (dnde) SED negative errors.

dnde_errp

Return differential flux (dnde) SED positive errors.

dnde_ref

Reference differential flux

dnde_ul

Return differential flux (dnde) SED upper limit.

e2dnde

Return differential energy flux (e2dnde) SED values.

e2dnde_err

Return differential energy flux (e2dnde) SED errors.

e2dnde_errn

Return differential energy flux (e2dnde) SED negative errors.

e2dnde_errp

Return differential energy flux (e2dnde) SED positive errors.

e2dnde_ref

Reference differential flux * energy ** 2

e2dnde_ul

Return differential energy flux (e2dnde) SED upper limit.

eflux

Return energy flux (eflux) SED values.

eflux_err

Return energy flux (eflux) SED errors.

eflux_errn

Return energy flux (eflux) SED negative errors.

eflux_errp

Return energy flux (eflux) SED positive errors.

eflux_ref

Reference energy flux

eflux_ul

Return energy flux (eflux) SED upper limits.

energy_axis

Energy axis (MapAxis)

energy_max

Energy max

energy_min

Energy min

energy_ref

Reference energy.

filter_success_nan

flux

Return integral flux (flux) SED values.

flux_err

Return integral flux (flux) SED values.

flux_errn

Return integral flux (flux) SED negative errors.

flux_errp

Return integral flux (flux) SED positive errors.

flux_ref

Reference integral flux

flux_ul

Return integral flux (flux) SED upper limits.

geom

Reference map geometry (Geom)

has_any_ts

Whether the flux estimate has either sqrt(ts) or ts defined

has_stat_profiles

Whether the flux estimate has stat profiles

has_success

Whether the flux estimate has the fit status

has_ul

Whether the flux estimate has norm_ul defined

is_convertible_to_flux_sed_type

Check whether differential sed type is convertable to integral sed type

is_ul

Whether data is an upper limit

n_sigma

n sigma

n_sigma_ul

n sigma UL

niter

Number of iterations of fit

norm

Norm values

norm_err

Norm error

norm_errn

Negative norm error

norm_errp

Positive norm error

norm_ul

Norm upper limit

npred

Predicted counts from best fit hypothesis

npred_background

Predicted background counts from best fit hypothesis

npred_excess

Predicted excess count rom best fit hypothesis

npred_excess_err

Predicted excess counts error

npred_excess_errn

Predicted excess counts negative error

npred_excess_errp

Predicted excess counts positive error

npred_excess_ref

Predicted excess reference counts

npred_excess_ul

Predicted excess counts upper limits

reference_model

Reference model (SkyModel)

reference_model_default

Reference model default (SkyModel)

reference_spectral_model

Reference spectral model (SpectralModel)

sed_type_init

Initial sed type

sed_type_plot_default

Initial sed type

sqrt_ts

sqrt(TS) as defined by:

sqrt_ts_threshold_ul

sqrt(TS) threshold for upper limits

stat

Fit statistic value

stat_null

Fit statistic value for the null hypothesis

stat_scan

Fit statistic scan value

success

Fit success flag

ts

ts map (Map)

ts_scan

ts scan (Map)

Methods Summary

all_quantities(sed_type)

All quantities allowed for a given sed type.

from_hdulist(hdulist[, hdu_bands, sed_type])

Create flux map dataset from list of HDUs.

from_maps(maps[, sed_type, reference_model, ...])

Create FluxMaps from a dictionary of maps.

from_stack(maps, axis[, meta])

Create flux points by stacking list of flux points.

get_flux_points([position])

Extract flux point at a given position.

iter_by_axis(axis_name[, keepdims])

Create a set of FluxMaps by splitting along an axis.

read(filename)

Read map dataset from file.

slice_by_idx(slices)

Slice flux maps by idx

to_hdulist([sed_type, hdu_bands])

Convert flux map to list of HDUs.

to_maps([sed_type])

Return maps in a given SED type.

write(filename[, filename_model, overwrite, ...])

Write flux map to file.

Attributes Documentation

available_quantities#

Available quantities

counts#

Predicted counts null hypothesis

dnde#

Return differential flux (dnde) SED values.

dnde_err#

Return differential flux (dnde) SED errors.

dnde_errn#

Return differential flux (dnde) SED negative errors.

dnde_errp#

Return differential flux (dnde) SED positive errors.

dnde_ref#

Reference differential flux

dnde_ul#

Return differential flux (dnde) SED upper limit.

e2dnde#

Return differential energy flux (e2dnde) SED values.

e2dnde_err#

Return differential energy flux (e2dnde) SED errors.

e2dnde_errn#

Return differential energy flux (e2dnde) SED negative errors.

e2dnde_errp#

Return differential energy flux (e2dnde) SED positive errors.

e2dnde_ref#

Reference differential flux * energy ** 2

e2dnde_ul#

Return differential energy flux (e2dnde) SED upper limit.

eflux#

Return energy flux (eflux) SED values.

eflux_err#

Return energy flux (eflux) SED errors.

eflux_errn#

Return energy flux (eflux) SED negative errors.

eflux_errp#

Return energy flux (eflux) SED positive errors.

eflux_ref#

Reference energy flux

eflux_ul#

Return energy flux (eflux) SED upper limits.

energy_axis#

Energy axis (MapAxis)

energy_max#

Energy max

Returns
energy_maxQuantity

Upper bound of energy bin.

energy_min#

Energy min

Returns
energy_minQuantity

Lower bound of energy bin.

energy_ref#

Reference energy.

Defined by energy_ref column in FluxPoints.table or computed as log center, if energy_min and energy_max columns are present in FluxEstimate.data.

Returns
energy_refQuantity

Reference energy.

filter_success_nan#
flux#

Return integral flux (flux) SED values.

flux_err#

Return integral flux (flux) SED values.

flux_errn#

Return integral flux (flux) SED negative errors.

flux_errp#

Return integral flux (flux) SED positive errors.

flux_ref#

Reference integral flux

flux_ul#

Return integral flux (flux) SED upper limits.

geom#

Reference map geometry (Geom)

has_any_ts#

Whether the flux estimate has either sqrt(ts) or ts defined

has_stat_profiles#

Whether the flux estimate has stat profiles

has_success#

Whether the flux estimate has the fit status

has_ul#

Whether the flux estimate has norm_ul defined

is_convertible_to_flux_sed_type#

Check whether differential sed type is convertable to integral sed type

is_ul#

Whether data is an upper limit

n_sigma#

n sigma

n_sigma_ul#

n sigma UL

niter#

Number of iterations of fit

norm#

Norm values

norm_err#

Norm error

norm_errn#

Negative norm error

norm_errp#

Positive norm error

norm_ul#

Norm upper limit

npred#

Predicted counts from best fit hypothesis

npred_background#

Predicted background counts from best fit hypothesis

npred_excess#

Predicted excess count rom best fit hypothesis

npred_excess_err#

Predicted excess counts error

npred_excess_errn#

Predicted excess counts negative error

npred_excess_errp#

Predicted excess counts positive error

npred_excess_ref#

Predicted excess reference counts

npred_excess_ul#

Predicted excess counts upper limits

reference_model#

Reference model (SkyModel)

reference_model_default#

Reference model default (SkyModel)

reference_spectral_model#

Reference spectral model (SpectralModel)

sed_type_init#

Initial sed type

sed_type_plot_default#

Initial sed type

sqrt_ts#

sqrt(TS) as defined by:

\[\begin{split}\sqrt{TS} = \left \{ \begin{array}{ll} -\sqrt{TS} & : \text{if} \ norm < 0 \\ \sqrt{TS} & : \text{else} \end{array} \right.\end{split}\]
Returns
sqrt_tsMap

sqrt(TS) map

sqrt_ts_threshold_ul#

sqrt(TS) threshold for upper limits

stat#

Fit statistic value

stat_null#

Fit statistic value for the null hypothesis

stat_scan#

Fit statistic scan value

success#

Fit success flag

ts#

ts map (Map)

ts_scan#

ts scan (Map)

Methods Documentation

static all_quantities(sed_type)[source]#

All quantities allowed for a given sed type.

Parameters
sed_type{“likelihood”, “dnde”, “e2dnde”, “flux”, “eflux”}

Sed type.

Returns
listlist of str

All allowed quantities for a given sed type.

classmethod from_hdulist(hdulist, hdu_bands=None, sed_type=None)[source]#

Create flux map dataset from list of HDUs.

Parameters
hdulistHDUList

List of HDUs.

hdu_bandsstr

Name of the HDU with the BANDS table. Default is ‘BANDS’ If set to None, each map should have its own hdu_band

sed_type{“dnde”, “flux”, “e2dnde”, “eflux”, “likelihood”}

Sed type

Returns
flux_mapsFluxMaps

Flux maps object.

classmethod from_maps(maps, sed_type=None, reference_model=None, gti=None, meta=None)[source]#

Create FluxMaps from a dictionary of maps.

Parameters
mapsMaps

Maps object containing the input maps.

sed_typestr

SED type of the input maps. Default is Likelihood

reference_modelSkyModel, optional

Reference model to use for conversions. Default in None. If None, a model consisting of a point source with a power law spectrum of index 2 is assumed.

gtiGTI

Maps GTI information. Default is None.

metadict

Meta dict.

Returns
flux_mapsFluxMaps

Flux maps object.

classmethod from_stack(maps, axis, meta=None)[source]#

Create flux points by stacking list of flux points.

The first FluxPoints object in the list is taken as a reference to infer column names and units for the stacked object.

Parameters
mapslist of FluxMaps

List of maps to stack.

axisMapAxis

New axis to create

Returns
flux_mapsFluxMaps

Stacked flux maps along axis.

get_flux_points(position=None)[source]#

Extract flux point at a given position.

Parameters
positionSkyCoord

Position where the flux points are extracted.

Returns
flux_pointsFluxPoints

Flux points object

iter_by_axis(axis_name, keepdims=False)[source]#

Create a set of FluxMaps by splitting along an axis.

Parameters
axis_namestr

Name of the axis to split on

keepdimsbool

Whether to keep the split axis with a single bin

Returns
flux_mapsFluxMap

FluxMap iteration

classmethod read(filename)[source]#

Read map dataset from file.

Parameters
filenamestr

Filename to read from.

Returns
flux_mapsFluxMaps

Flux maps object.

slice_by_idx(slices)[source]#

Slice flux maps by idx

Parameters
slicesdict

Dict of axes names and integers or slice object pairs. Contains one element for each non-spatial dimension. For integer indexing the corresponding axes is dropped from the map. Axes not specified in the dict are kept unchanged.

Returns
flux_mapsFluxMaps

Sliced flux maps object.

to_hdulist(sed_type=None, hdu_bands=None)[source]#

Convert flux map to list of HDUs.

For now, one cannot export the reference model.

Parameters
sed_typestr

sed type to convert to. Default is Likelihood

hdu_bandsstr

Name of the HDU with the BANDS table. Default is ‘BANDS’ If set to None, each map will have its own hdu_band

Returns
hdulistHDUList

Map dataset list of HDUs.

to_maps(sed_type=None)[source]#

Return maps in a given SED type.

Parameters
sed_type{“likelihood”, “dnde”, “e2dnde”, “flux”, “eflux”}

sed type to convert to. Default is Likelihood

Returns
mapsMaps

Maps object containing the requested maps.

write(filename, filename_model=None, overwrite=False, sed_type=None)[source]#

Write flux map to file.

Parameters
filenamestr

Filename to write to.

filename_modelstr

Filename of the model (yaml format). If None, keep string before ‘.’ and add ‘_model.yaml’ suffix

overwritebool

Overwrite file if it exists.

sed_typestr

sed type to convert to. Default is likelihood