Cosmic Infrared Background anisotropies and galaxy spectra
This animation shows the anisotropies observed by Planck in the Cosmic Infrared Background at different frequencies. Along with each map is shown the typical spectrum of a galaxy at the redshift to which the corresponding frequency channel is most sensitive.
Moving across the various frequencies probed by Planck's High Frequency Instrument, the amount and extent of structure observed are rather different, as a consequence of the fact that each frequency channel is most sensitive to the emission coming from galaxies at a certain redshift. Observations at the highest frequency, corresponding to 857 GHz, yield most information about galaxies up to z~1, whereas the lower frequencies offer a chance to peer farther and farther away, out to z~1–4, thus emphasising Planck's ability to track down the early phases of galaxy formation.