Cosmic Microwave Background Anisotropy Measurement from Python V

We analyze observations of the microwave sky made with the Python experiment in its fifth year of operation at the Amundsen-Scott South Pole Station in Antarctica. After modeling the noise and constructing a map, we extract the cosmic signal from the data. We simultaneously estimate the angular power spectrum in eight bands ranging from large (‘ 40) to small (‘ 260) angular scales, with power detected in the first six bands. There is a significant rise in the power spectrum from large to smaller (‘ 200) scales, consistent with that expected from acoustic oscillations in the early universe. We compare this Python V map to a map made from data taken in the third year of Python. Python III observations were made at a frequency of 90 GHz and covered a subset of the region of the sky covered by Python V observations, which were made at 40 GHz. Good agreement is obtained both visually (with a filtered version of the map) and via a likelihood ratio test. Subject headings: cosmic microwave background — cosmology: observations On-line material: color figures