Implications of faint radio sources for star formation history

Faint radio sources provide important information about global star formation history. We make use of the correlation between radio and far infrared (FIR) flux to study the faint star forming galaxies producing the FIR and radio extragalactic background emission. Combining this with the typical radio spectral indices of these sources and their number counts, we estimate their mean redshift to be roughly between 1 and 2. In a. second calculation, we use a simple model of the redshift distribution of faint radio sources, in combination with the number count information, to calculate the peak star formation rate density, which we can do without knowledge of the luminosity function.