Observations of the Extragalactic Background Light

Abstract

We present a review of the presently available observations of the extragalactic background light (EBL) obtained by means of night sky photometry. The EBL is a quantity of great cosmological importance; areas which are directly affected include galaxy formation and evolution, the appropriateness of different cosmological models, and the local luminosity density due to galaxies and other matter in intergalactic space. The basic problem in measuring the EBL is its separation from other, much stronger components of the light of the night sky. None of the different observational techniques have succeeded in providing a generally accepted measurement of the EBL. After a review of available methods, we present new results from an experiment by Mattila and Schnur (1989) utilizing the dark cloud technique in the area of L1642, a high-latitude dark nebula in the galactic anticentre direction.