ar X iv : a st ro - p h / 96 03 12 1 v 1 2 2 M ar 1 99 6 Contribution of Extragalactic Infrared Sources to CMB Foreground Anisotropy

Received ; accepted – 2 – ABSTRACT We estimate the level of confusion of Cosmic Microwave Background (CMB) anisotropy measurements caused by extragalactic infrared sources. CMB anisotropy observations at high resolution and high frequencies are especially sensitive to this foreground. We have combined IRAS data on bright infrared galaxies with information about the Galaxy from the DIRBE and FIRAS instruments of COBE. Using the spectrum of the Milky Way as a template, we predict the microwave emission of the 5319 brightest infrared galaxies. We simulate skymaps of extragalactic infrared sources over the relevant range of frequencies (30-900 GHz) and instrument resolutions (10 ′ − 10 • Full Width Half Max). Analysis of the temperature anisotropy of these skymaps shows a level of extragalactic infrared foreground that is nearly consistent with previous estimates based on galaxy-evolution models. A reasonable observational window is still available for medium-and small-angular scale CMB anisotropy measurements. infrared galaxies – infrared sources: extragalactic – 3 –