Correlations in the Far‐Infrared Background

We compute the expected angular power spectrum of the cosmic Far InfraredBackground (FIRB). We find that the signal due to source correlations dominatesthe shot--noise for $\ell \la 1000$ and results in anisotropies with rmsamplitudes $(\sqrt{\ell(\ell+1)C_\ell/2\pi})$ between 5% and 10% of the meanfor $l \ga 150$. The angular power spectrum depends on several unknownquantities, such as the UV flux density evolution, optical properties of thedust, biasing of the sources of the FIRB, and cosmological parameters. However,when we require our models to reproduce the observed DC level of the FIRB, wefind that the anisotropy is at least a few percent in all cases. Thisanisotropy is detectable with proposed instruments, and its measurement willprovide strong constraints on models of galaxy evolution and large-scalestructure at redshifts up to at least $z \sim5$.Comment: 7 pages, 4 figures included, uses emulateapj.sty. More models explored than in original version. Accepted for publication in Ap