Low-Frequency Measurements of the CMB Spectrum

• Main Authors: Kogut, A., Bensadoun, M., De Amici, Giovanni, Levin, S., Limon,M., Smoot, George F., Sironi, G., Bersanelli, M., Bonelli, G.
• Language: unknown
• Published: 2009
• Subjects: 71 CLASSICAL AND QUANTUM MECHANICS; GENERAL PHYSICS; RELICT RADIATION; ASTROPHYSICS; LAWRENCE BERKELEY LABORATORY; Amundsen-Scott; South Pole; South pole
• Online Access: http://www.osti.gov/servlets/purl/893048; https://www.osti.gov/biblio/893048

As part of an extended program to characterize the spectrum of the cosmic microwave background (CMB) at low frequencies, we have performed multiple measurements from a high-altitude site in California. On average, these measurements suggest a CMB temperature slightly lower than measurements at higher frequencies. Atmospheric conditions and the encroachment of civilization are now significant limitations from our present observing site. In November 1989, we will make new measurements from the South Pole Amundsen-Scott Station at frequencies 0.82, 1.5, 2.5, 3.8, 7.5, and 90 GHz. We discuss recent measurements and indicate improvements possible from a polar observing site.