plot_bkg

sherpa.astro.ui.plot_bkg(id: IdType | IdTypes | None = None, bkg_id: IdType | None = None, replot: bool = False, overplot: bool = False, clearwindow: bool = True, **kwargs) → None

Plot the background values for a PHA data set.

Changed in version 4.18.0: Multiple data sets can be displayed by using a list of identifiers. Per-plot options can now be given by using a list of values.

Parameters:

idint, str, sequence of int or str, or None, optional: The data set that provides the data. If not given then the default identifier is used, as returned by get_default_id.
bkg_idint, str, or None, optional: Identify the background component to use, if there are multiple ones associated with the data set.
replotbool, optional: Set to True to use the values calculated by the last call to plot_bkg. The default is False.
overplotbool, optional: If True then add the data to an existing plot, otherwise create a new plot. The default is False.
clearwindowbool, optional: Should the existing plot area be cleared before creating this new plot (e.g. for multi-panel plots)?

Raises:

sherpa.utils.err.ArgumentErr: If the data set does not contain PHA data.
sherpa.utils.err.IdentifierErr: If the bkg_id parameter is invalid.

See also

get_bkg_plot: Return the data used by plot_bkg.
get_default_id: Return the default data set identifier.
plot: Create one or more plot types.
set_analysis: Set the units used when fitting and displaying spectral data.
set_xlinear: New plots will display a linear X axis.
set_xlog: New plots will display a logarithmically-scaled X axis.
set_ylinear: New plots will display a linear Y axis.
set_ylog: New plots will display a logarithmically-scaled Y axis.

Examples

Plot the background from the default data set:

>>> plot_bkg()

Overplot the background from the ‘jet’ data set on the data. There is no scaling for differences in aperture or exposure time:

>>> plot_data('jet')
>>> plot_bkg('jet', overplot=True)

Compare the first two background components of data set 1:

>>> plot_bkg(1, 1)
>>> plot_bkg(1, 2, overplot=True)

Plot background components for datasets “flare” and “quiet”:

>>> plot_bkg(["flare", "quiet"], alpha=0.5)