Left: against redshift. The ordinate on the right-hand side of the plot is calculated using Eq. (2) assuming a radiative conversion efficiency ϵ = 0.1 and (Sect. 6.1.2). Right: against redshift. The ordinate on the right-hand side of the plot is calculated using Eq. (1), assuming the Kennicutt (1998) law. We indicate our average 3σ-sensitivity limit for the AGN and the SB3 templates for each filter (see Sect. 5.1 for details, figure inspired by Elbaz et al. 2011). It can be seen that in a case of pure AGN emission, MIPS (24  μm) is the most sensitive band over the entire redshift range, while in the case of a pure starburst emission, the most sensitive band at z> 2 is in the submm (APEX or SCUBA).