High‐Resolution Observations of the Cosmic Microwave Background Power Spectrum with ACBAR

Abstract

We report the first measurements of anisotropy in the cosmic microwave background (CMB) radiation with the Arcminute Cosmology Bolometer Array Receiver (ACBAR). The instrument was installed on the 2.1 m Viper telescope at the South Pole in 2001 January; the data presented here are the product of observations up to and including 2002 July. We present two deep differential maps produced by subtracting leading and trailing observations from the main field. The differential maps cover approximately 24 deg2 of sky selected for low dust contrast. These results represent the highest signal-to-noise ratio observations of CMB anisotropy to date; in the deepest 150 GHz band map, we reached an rms of ~8.0 ?K per 5' beam. The 3