# plot_bkg_fit_delchi¶

sherpa.astro.ui.plot_bkg_fit_delchi(id=None, bkg_id=None, replot=False, overplot=False, clearwindow=True, **kwargs)

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

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.

• replot (bool, optional) – Set to True to use the values calculated by the last call to plot_bkg_fit_delchi. The default is False.

• overplot (bool, optional) – If True then add the data to an exsiting plot, otherwise create a new plot. The default is False.

• clearwindow (bool, optional) – Should the existing plot area be cleared before creating this new plot (e.g. for multi-panel plots)?

Raises

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()