Producing Megapixel Cosmic Microwave Background Maps from Differential Radiometer Data

A major goal of cosmology is to obtain sensitive, high resolution maps of theCosmic Microwave Background (CMB) anisotropy. Such maps, as would be producedby the recently proposed Microwave Anisotropy Probe (MAP), will contain awealth of primary information about conditions in the early universe. Tomitigate systematic effects when observing the microwave background, it isdesirable for the raw data to be collected in differential form: as a set oftemperature differences between points in the sky. However, the production oflarge (mega-pixel) maps from a set of temperature differences is a potentiallysevere computational challenge. We present a new technique for producing mapsfrom differential radiometer data that has a computational cost that grows inthe slowest possible way with increasing angular resolution and number of mappixels. The required central processor (CPU) time is proportional to the numberof differential data points and the required random access memory (RAM) isproportional to the number of map pixels. We test our technique, anddemonstrate its feasibility, by simulating one year of a space-borne anisotropymission.Comment: 8 pages Latex with 3 Postscript figures embedded using eps