Same as Fig. 2 but includes grey points from the Spitzer Deep Wide Field Survey representing the expected regions of contamination from non-M 83 sources. Note that only the more luminous and bluer RSG candidates lie distinctly outside the contaminated region. For reference, also plotted are the locations of the prominent evolved massive stars η Car (Humphreys & Davidson 1994), M 33 Variable A (Humphreys et al. 2006), Object X (Khan et al. 2011), when placed at the distance (~4.8 Mpc) of M 83.