Integrated far-infrared background from galaxies

The integrated radiation from galaxies is calculated at far-IR and submillimeter wavelengths. The peak of the far-IR background radiation is 100-130 microns, and its total energy content is 0.5-6 percent of the cosmic microwave background (CMB). At wavelengths longward of 400 microns, the CMB dominates over the far-IR radiation from galaxies in intensity. The autocorrelation of fluctuations from the average angle of the far-IR background of galaxies is calculated. The contribution of galaxies to the anisotropy of the background radiation at wavelengths longer than about 400 microns where the CMB is predominant is obtained. It is found that, in general, earlier galaxy formation predicts stronger far-IR background radiation. The prompt initial enrichment model for the chemical evolution of disk galaxies, in particular those with an exponential star formation rate, produces much larger intensity of the integrated radiation than the accretion model.