XMM-Newton Science Analysis System


specgroup (specgroup-1.7.1) [22.0.0-9173c7d25-20250127]

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)