Atacama Cosmology Telescope (ACT)The beam window functions for the ACT temperature power spectra are computed at 148 GHz and 218 GHz. They are obtained by transforming the beam profiles obtained from Saturn observations. The errors are estimated by fitting a small set of basis functions to the beam profile, with the window function covariance matrix derived from the covariance of the coefficients of the basis functions. The normalization of the window functions are fixed to unity at l=700, and the calibration error factored out of the covariance matrix, so the window functions have zero error at, l=700. The window functions are given in a separate file for each frequency with the following columns: the mean multipole moment l There is also a decomposed beam window function covariance matrix for use in likelihood analyses, found in the ACT likelihood tarball. Version v2a1 (September 2010)  first ACT 2008 release Additional Details
