get_bkg_ratio_plot

sherpa.astro.ui.get_bkg_ratio_plot(id=None, bkg_id=None)

Return the data used by plot_bkg_ratio.

Parameters:

• id (int or str, optional) – The data set that provides the data. If not given then the default identifier is used, as returned by get_default_id.
• bkg_id (int or str, optional) – Identify the background component to use, if there are multiple ones associated with the data set.

Returns:

source – An object representing the data used to create the plot by plot_bkg_ratio.

Return type:

a sherpa.astro.plot.BkgRatioPlot instance

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.
• sherpa.utils.err.ModelErr – If no model expression has been created for the background data.

See also

get_bkg_chisqr_plot()

Return the data used by plot_bkg_chisqr.

get_bkg_delchi_plot()

Return the data used by plot_bkg_delchi.

get_bkg_resid_plot()

Return the data used by plot_bkg_resid.

plot_bkg_ratio()

Plot the ratio of data to model values for the background of a PHA data set.