New Methods of Investigation for Extragalactic Backgrounds in the Infrared

If we look at the infrared sky between 1 and 1000 µm we observe several contributions to the background coming from different parts and/or epochs of the universe. We consider the problem of distinguishing between ‘local’ contributions (planetary and galactic dust, atmospheric emission, dashed lines) and the extragalactic backgrounds. In the figure are shown the computed emissions for rich clusters of galaxies (IRG) and integrated infrared galaxies (IRG). CMB is the cosmic microwave background.