ACT (MBAC) Data Products - 2008 Beams

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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
-the window function W_l (such that e.g. Cl^observed = W_l C_l)
-the 1-sigma error on the window function

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

  • "The Atacama Cosmology Telescope: A Measurement of the Cosmic Microwave Background Power Spectrum at 148 and 218 GHz from the 2008 Southern Survey," S. Das, et.al. (2010) [eprint arXiv:1009.0847]
  • "The Atacama Cosmology Telescope (ACT): Beam Profiles and First SZ Cluster Maps," A. Hincks, et.al. (2010), [eprint arXiv:0907.0461, ApJS, 191, 423]

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