Max Tegmark's library: polarization
A sample window function for the Boomerang 2001 experiment showing how
unwanted B-polarization power leaks into an estimate of E-power.
Please click here to get a postscript file with
you are interested in other research of mine.
How to measure CMB polarization power spectra
without losing information
Angelica de Oliveira-Costa
We present a method for measuring CMB polarization power spectra
given incomplete sky coverage and test it with simulated
examples such as Boomerang 2001 and MAP.
By augmenting the quadratic estimator method
with an additional step, we find that the E and B power spectra
can be effectively disentangled on angular scales
substantially smaller than the width of the sky patch in the
We find that the basic quadratic and maximum-likelihood methods
display a unneccesary sensitivity to systematic errors when
T-E cross-correlation is involved, and show how this problem can be
eliminated at negligible cost in increased error bars.
We also test numerically the widely used approximation
that sample variance scales inversely with sky coverage,
and find it to be an excellent approximation on scales
substantially smaller than the sky patch.
astro-ph/0012120, submitted to Phys. Rev. D
This paper is part of an ongoing effort to develop useful data analysis
methods for cosmology. For info on various aspects of the CMB analysis pipeline,
or on the meat mincer below.
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This page was last modified November 7, 2000.