An absolute measurement of the cosmic microwave background radiation temperature at 20 centimeters

S. T. Staggs, N. C. Jarosik, D. T. Wilkinson, E. J. Wollack

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

A ground-based radiometer is used to measure the absolute temperature of the cosmic microwave background radiation (CMBR) at a frequency of 1.4 GHz. The instrument comprises a corrugated horn antenna coupled to a cryogenic correlation receiver. Accurate gain calibrations are made every few minutes; the radiometer zero offset is measured at the beginning and the end of the observing season. Tip scans are made to measure the atmospheric emission. We find Tatm = 1550 ± 170 mK for a pencil beam, measured from an elevation of 836 m. The Galactic foreground emission is removed by extrapolation from a lower frequency map. Over the region observed, the Galactic component is ∼ 1 K and varies by ∼ 10%. Cold loads are-used to measure the instrumental emission. The ability to sample narrow (5 MHz) frequency bins across a 5% bandpass provides a powerful tool for studying systematic effects. For the absolute temperature of the CMBR, we find TCMBR = 2.65-0.30+0.33 K. This result is higher, but not significantly, than the value of TCMBR at 1.4 GHz previously reported by Bensadoun et al.

Original languageEnglish (US)
Pages (from-to)407-418
Number of pages12
JournalAstrophysical Journal
Volume458
Issue number2 PART I
DOIs
StatePublished - 1996

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Cosmic microwave background
  • Cosmology: observations
  • Diffuse radiation

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