plot_bkg_ratio

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

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

Display the ratio of data to model values for the background of a PHA data set when it is being fit, rather than subtracted from the source.

Changed in version 4.12.0: The Y axis 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_ratio. 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

See also

get_bkg_ratio_plot()

Return the data used by plot_bkg_ratio.

plot_bkg_chisqr()

Plot the chi-squared value for each point of the background of a PHA data set.

plot_bkg_delchi()

Plot the ratio of residuals to error for the background of a PHA data set.

plot_bkg_resid()

Plot the residual (data-model) values for the background of a PHA data set.

set_bkg_model()

Set the background model expression for a PHA data set.

Notes

The ylog setting is ignored, and the Y axis is drawn using a linear scale.

Examples

>>> plot_bkg_ratio()
>>> plot_bkg_ratio('jet', bkg_id=1)
>>> plot_bkg_ratio('jet', bkg_id=2, overplot=True)