We have predicted extragalactic number counts and diffuse backgrounds at 25, 60, and 100 microns using new luminosity functions and improved spectral energy distribution density functions derived from IRAS observations of nearby galaxies. Galaxies at redshifts z < 3 that are like those in the local universe should produce a minimum diffuse background of 8.5 x 10^-3^, 3.8 x 10^-2^, and 0.13 MJy sr^-1^ at 25, 60, and 100 microns, respectively. Models with significant luminosity evolution predict backgrounds about a factor of 4 greater than this minimum. Strong luminosity evolution of infrared-bright galaxies can be excluded based on the predicted high fractions of sources at z > 0.5 that do not appear in the many redshift surveys of infrared-bright galaxies conducted to date. The minimum predicted background should be detectable by COBE at 100 microns and might be detected at 60 microns. COBE will probably not detect the 25 micron background. The next generation of space missions (e.g., ISO and SIRTF) will easily detect and characterize the evolution of infrared- bright star-forming galaxies.
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Hacking et al. (1991) studied this question.