Max Tegmark's library: brute.ps
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A BRUTE FORCE ANALYSIS OF THE COBE DMR DATA
Authors: Max Tegmark & Ted Bunn
More than a dozen papers analyzing the COBE data have now appeared.
We review the different techniques
and compare them to a ``brute force"
where we invert the full 4038 x 4038 Galaxy-cut pixel
This method is optimal in the sense of producing
minimal error bars, and is a useful reference point for comparing
other analysis techniques.
Our maximum-likelihood estimate of the spectral index and normalization
are n=1.15 (0.95) and Q=18.2 (21.3) micro-Kelvin
including (excluding) the
quadrupole. Marginalizing over the normalization C_9,
n=1.10 +/- 0.29 (n=0.90 +/- 0.32).
When we compare these results with those of
the various techniques that involve
a linear ``compression'' of the data, we find that the latter
are all consistent with the brute-force analysis and have error bars
that are nearly as small as the minimal error bars. We therefore conclude
that the data compressions involved in these techniques do indeed retain
most of the useful cosmological information.
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This page was last modified July 1, 1998.