We report on a measurement of the angular spectrum of the cosmic microwave background (CMB) between l ≈ 100 and l ≈ 400 made at 144 GHz from Cerro Toco in the Chilean altiplano. When the new data are combined with previous data at 30 and 40 GHz taken with the same instrument observing the same section of sky, we find (1) a rise in the angular spectrum to a maximum with δTl ≈ 85 μK at l ≈ 200 and a fall at l > 300, thereby localizing the peak near l ≈ 200, and (2) that the anisotropy at l ≈ 200 has the spectrum of the CMB.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
- Cosmic microwave background
- Cosmology: observations