plot_bkg_fit_delchi

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

Plot the fit results, and the residuals, for the background of a PHA data set.

This creates two plots - the first from plot_bkg_fit and the second from plot_bkg_delchi - for a 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.

Changed in version 4.12.2: The overplot option now works.

Changed in version 4.12.0: The Y axis of the residual plot is now always drawn using a linear scale.

Parameters:

idint, 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_fit_delchi. 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.
sherpa.utils.err.ModelErr: If no model expression has been created for the background data.

See also

get_bkg_fit_plot: Return the data used by plot_bkg_fit.
get_bkg_delchi_plot: Return the data used by plot_bkg_delchi.
plot: Create one or more plot types.
plot_bkg: Plot the background values for a PHA data set.
plot_bkg_model: Plot the model for the background of a PHA data set.
plot_bkg_fit: Plot the fit results (data, model) for the background of a PHA data set.
plot_bkg_fit_ratio: Plot the fit results, and the data/model ratio, for the background of a PHA data set.
plot_bkg_fit_resid: Plot the fit results, and the residuals, for the background of a PHA data set.
plot_fit: Plot the fit results (data, model) for a data set.
plot_fit_delchi: Plot the fit results, and the residuals, for a data set.
set_analysis: Set the units used when fitting and displaying spectral data.

Notes

For the residual plot, the ylog setting is ignored, and the Y axis is drawn using a linear scale.

Examples

Plot the background fit and residuals (normalised by the error) to the default data set:

>>> plot_bkg_fit_delchi()