This award will support a group of investigators headed by Professor George Smoot of the University of California-Berkeley in collaborative work with Professor Giorgio Sironi of the Universita Degli Studi di Milano in Milan, Italy. The investigators plan to carry out improved measurements of the cosmic microwave background radiation (CMBR) temperature from the Amundsen-Scott South Pole Station. The Italian group will make measurements at frequencies of .8 and 2.5 GHz, while the U.S. team will make measurements at frequencies of 1.5, 3.8, and 7.5 GHz. Already, measurements taken by 2.5 and 3.8 GHz radiometers have yielded scientifically significant results; with upgraded equipment and the more advantageous South Pole site, it is expected that more accurate results will be obtained that will supplement, verify, and extend previous measurements by the collaborators. In addition, atmospheric measurements in the 90GHz range will be done, using existing instruments. In combination with current measurements at higher frequencies and with very accurate high frequency data from the Cosmic Background Explorer (CoBE) satellite, these measurements will more accurately determine the shape of the CMBR spectrum and thus provide useful information about the thermal history of the early universe, significantly affecting theories of galaxy formation and particle physics. In addition, the atmospheric measurement could help test existing models of atmospheric emission by providing valuable data taken with a single set of instruments over a wide range of atmospheric and meteorological conditions.
