XMM-Newton Science Analysis System


specgroup (specgroup-1.6) [xmmsas_20160201_1833-15.0.0]

Meta Index / Home Page / Grouping options and examples / Statistical grouping

Minimum signal-to-noise ratio

This sets spectral groups such that each group contains a minimum signal-to-noise ratio (S/N). The calculation of the ratio will take the area-normalised background into account if a background spectrum is provided. e.g.:

would make groups with a minimum S/N of 6 where S/N is given by:

$$S/N = ( source - background * areanorm ) / sqrt( source + background * areanorm^2)$$ (1)