The Structure of Symposium 204

Abstract

The extragalactic infrared background touches on many topics: The rate at which energy was generated in stars at different epochs; the corresponding number counts of galaxies observed at different redshifts; the related rate at which non-primordial helium and the heavy chemical elements were produced at these same epochs; the abundances of these elements that can be found in damped Lyman-alpha absorbers at commensurate redshifts; the abundances of the same elements in Galactic stars formed at similar epochs; the integrated supernova rates over all epochs, and the number of neutron stars and black holes in our locale within the Universe today. The distances from which TeV gamma-rays at different energies can reach us are also intimately related to the infrared background spectrum. The purpose of this Symposium was to seek a coherent picture into which all these pieces of observational evidence can be satisfactorily fitted. This was the rationale in setting up the invited talks.