How should we analyze microwave sky maps?
Dec, 1994Citations per year
Abstract: (arXiv)
More than a dozen papers analyzing the COBE data have now appeared, and the profusion of different methods may leave the reader slightly bewildered and confused. We review the different techniques and compare them to a ``brute force" likelihood analysis where we invert the full Galaxy-cut pixel covariance matrix. This method is optimal in the sense of producing minimal error bars, and is a useful reference point when ranking other analysis techniques. Our maximum likelihood estimate of the spectral index and normalization are and \Q = 18.2 (21.3) \mK including (excluding) the quadrupole. Marginalizing over the normalization \expec{a_5}, we obtain (). The reason that some methods produce slightly higher -estimates may be attributable to ``dipole bias". This bias is introduced when removing the monopole, dipole and quadrupole, as this procedure inadvertently removes also part of the other low multipoles (since the Galactic cut has destroyed the orthogonality) and we show how to correct for it.References(12)
Figures(0)