Near-millimeter spectrum of the microwave background

Journal Article · Sat Aug 15 04:00:00 EDT 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159126· OSTI ID:5849967

Woody, D P; Richards, P L

A complete description is given of a measurement of the spectrum of the cosmic microwave background (CMB). A fully calibrated, liquid helium cooled, ballon borne spectrophotometer was used to measure the emission spectrum of the night sky over the frequency range from 1.7 to 40 cm/sup -1/. Great care was taken with the instrumental design to avoid radiation from the Earth or the apparatus. The apparatus was calibrated using a blackbody source with a variety of temperatures before and after the flight. The atmospheric emission was subtracted by fitting the data to the spectrum computed from an atmospheric model. The resulting spectral measurements have a flux accuracy of better than 10% of the peak flux of a 3 K blackbody and extend over the frequency range from 2.5 to 24 cm/sup -1/. They show that the spectrum of the CMB peaks at 6 cm/sup -1/ and is approximately that of a blackbody out to several times that frequency. Some deviations from blackbody shape are observed. The measured flux is equivalent to that from a blackbody in the temperature range from 2.88 to 3.09 K. These measurements are combined with previous observations of the CMB to produce a set of data covering three decades in frequency. This data set is compared with various models of the CMB.

• Research Organization: Department of Physics, University of California; and Materials and Molecular Research Division, Lawrence Berkeley Laboratory
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5849967
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 248:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANTENNAS
BACKGROUND RADIATION
BLACKBODY RADIATION
CALIBRATION
COSMIC RADIATION
DATA ANALYSIS
EARTH ATMOSPHERE
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
EMISSIVITY
EQUIPMENT
IONIZING RADIATIONS
MATHEMATICS
MEASURING INSTRUMENTS
MICROWAVE RADIATION
MICROWAVE SPECTRA
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATION FLUX
RADIATIONS
SPECTRA
SPECTROPHOTOMETERS
STATISTICS
SURFACE PROPERTIES