Planck Early Results XVIII: The power spectrum of cosmic infrared
  background anisotropies
  Using Planck maps of six regions of low Galactic dust emission with a total
area of about 140 square degrees, we determine the angular power spectra of
cosmic infrared background (CIB) anisotropies from multipole l = 200 to l =
2000 at 217, 353, 545 and 857 GHz. We use 21-cm observations of HI as a tracer
of thermal dust emission to reduce the already low level of Galactic dust
emission and use the 143 GHz Planck maps in these fields to clean out cosmic
microwave background anisotropies. Both of these cleaning processes are
necessary to avoid significant contamination of the CIB signal. We measure
correlated CIB structure across frequencies. As expected, the correlation
decreases with increasing frequency separation, because the contribution of
high-redshift galaxies to CIB anisotropies increases with wavelengths. We find
no significant difference between the frequency spectrum of the CIB
anisotropies and the CIB mean, with Delta I/I=15% from 217 to 857 GHz. In terms
of clustering properties, the Planck data alone rule out the linear scale- and
redshift-independent bias model. Non-linear corrections are significant.
Consequently, we develop an alternative model that couples a dusty galaxy,
parametric evolution model with a simple halo-model approach. It provides an
excellent fit to the measured anisotropy angular power spectra and suggests
that a different halo occupation distribution is required at each frequency,
which is consistent with our expectation that each frequency is dominated by
contributions from different redshifts. In our best-fit model, half of the
anisotropy power at l=2000 comes from redshifts z<0.8 at 857 GHz and z<1.5 at
545 GHz, while about 90% come from redshifts z>2 at 353 and 217 GHz,
respectively.
