The cosmic infrared background: Measurements and implications

The cosmic infrared background records much of the radiant energy released by processes of structure formation that have occurred since the decoupling of matter and radiation following the Big Bang. In the past few years, dat a from the Cosmic Background Explorer (COBE) mission provided the first mea surements of this background, with additional constraints coming from studi es of the attenuation of TeV gamma -rays. At the same time, there has been rapid progress in resolving a significant fraction of this background with the deep galaxy counts at infrared wavelengths from the Infrared Space Obse rvatory (ISO) instruments and at submillimeter wavelengths from the Submill imeter Common User Bolometer Array (SCUBA) instrument. This article reviews the measurements of the infrared background and sources contributing to it and discusses the implications for past and present cosmic processes.