**XMM-Newton Science Analysis System
**

specgroup (specgroup-1.7.1) [xmmsas_20211130_0941-20.0.0]

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:

(1)

XMM-Newton SOC -- 2021-11-30