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Absolute measurement of the cosmic microwave background at 2 GHz
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1994
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The study measured the cosmic microwave background intensity at 2 GHz using a ground‑based total‑power radiometer. Observations were conducted from a high‑altitude site near the Amundsen‑Scott South Pole Station, with the radiometer calibrated against a quasi‑free‑space cold load and atmospheric and Galactic emissions subtracted via direct measurements, extrapolation, and low‑frequency map scaling. The CMB thermodynamic temperature was found to be 2.55 ± 0.14 K, about one sigma below the COBE‑FIRAS value, and the sky temperature at the south celestial pole was 2.83 ± 0.10 K, limited by atmospheric subtraction. Published in The Astrophysical Journal (1994) DOI 10.1086/173910.
view Abstract Citations (45) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Absolute Measurement of the Cosmic Microwave Background at 2 GHz Bersanelli, M. ; Bensadoun, M. ; de Amici, G. ; Levin, S. ; Limon, M. ; Smoot, G. F. ; Vinje, W. Abstract We measured the intensity of the cosmic microwave background (CMB) radiation at a frequency of 2.0 GHz (15 cm wavelength) with a ground- based total-power radio-frequency (RF) gain radiometer calibrated at the antenna aperture with a quasi-free space cold load. The observations were performed from a remote, high-altitude site near the Amundsen-Scott South Pole Station to minimize systematic effects. The measured thermodynamic temperature of the CMB is T_CMB_ = 2.55 +/- 0.14 K (68% confidence level), the limiting factors in the accuracy being the subtraction of the atmospheric and Galactic contributions. The atmospheric emission was evaluated both by direct measurements and by extrapolation from our higher frequency data. The Galactic emission was determined by scaling low-frequency maps and was checked with differential drift scans. Our result is ~1 σ lower than the recent accurate value of T_CMB_ obtained by COBE-FIRAS above 60 GHz. The temperature of the sky (i.e., CMB plus Galaxy and extragalactic sources) at the south celestial pole with ~22x resolution is T_A,Sky_ = 2.83 +/- 0.10 K, and its accuracy is limited by the subtraction of atmospheric emission. Publication: The Astrophysical Journal Pub Date: April 1994 DOI: 10.1086/173910 Bibcode: 1994ApJ...424..517B Keywords: Atmospheric Correction; Background Radiation; Cosmology; Galactic Radiation; Microwaves; Radio Astronomy; Space Temperature; Cosmic Background Explorer Satellite; Error Analysis; Microwave Radiometers; Milky Way Galaxy; Radio Antennas; Radio Frequency Interference; Solar Radiation; Astrophysics; COSMOLOGY: COSMIC MICROWAVE BACKGROUND; RADIO CONTINUUM: GENERAL full text sources ADS |