Degree Scale Anisotropy: Sp94 Results

We present results from two observations of the cosmic microwave background (CMB) performed from the South Pole during the 1993-1994 austral summer. Each observation employed a 3◦ peak to peak sinusoidal, single difference chop and consisted of a 20◦ × 1◦ strip on the sky near our SP91 observations. The first observation used a receiver which operates in 3 bands between 38 and 45 GHz (Q-band) with a FWHM beam which varies from 1◦ to 1◦ · 15. The second observation overlapped the first observation and used a receiver which operates in 4 bands between 26 and 36 GHz (Ka-band) with a FWHM beam which varies from 1◦ · 25 to 1◦ · 7. The Ka-band system has a similar beamsize and frequency coverage as the system used in our SP91 results. Significant correlated structure is observed in all bands for each observation. The spectrum of the structure is consistent with a CMB spectrum and is formally inconsistent with diffuse synchrotron and free-free emission at the 5 σ level. The amplitude of the structure is inconsistent with 20 K interstellar dust; however, the data do not discriminate against flat or inverted spectrum point sources. The root mean square amplitude (±1σ) of the combined (Ka+Q) data is ∆Trms = 42.0 +15.8 −6.8 μK for an average window function which has a peak value of 0.97 at l = 68 and drops to e−0.5 of the peak value at l = 36 and l = 106. A band power estimate of the CMB power spectrum, Cl, gives 〈 Cll(l+1) 2π 〉 B = 1.77 −0.54 × 10 −10. The band power estimates for the individual Ka and Q-band results are larger than but consistent with the band power estimate of the combined Ka-band SP91 results. Subject headings: cosmic microwave background — cosmology: observations