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Cosmic Background Imager |
Here we present supplementary numerical data for the CBI polarization observations reported by J. L. Sievers et al. (preprinted as astro-ph/0509203). If you use these data in a publication, please cite the appropriate papers and also give the URL of this web page and the date of publication (given at the bottom of this page).
The data are in the gzipped tar file cbipol_2.0_final.tar.gz (2.6 Mbyte)
The spectrum is contained in CBIpol_2.0_final.newdat
This data file should work as-is with current versions of COSMOMC
(Lewis & Bridle, 2002)
File format:
first line - location of window functions (should be properly set).
second line - total bands in each polarization. Order is
TT,EE,BB,TB,TE,EB
next lines (BAND_SELECTION) - select which bands are to be used in
parameter fitting. As mentioned in the paper, we drop the lowest
T bin (both in TT and TE).
next line: (1 1.00 0.026) - only number of relevance is 0.026, which
is the CBI calibration uncertainty in power (1.3% in amplitude)
(ignorable line)
iliketype - COSMOMC/.newdat format support offset-lognormal
approximation to the likelihood (Bond, Jaffe, and Knox 2000).
iliketype=2 lets the use of the offset-lognormal
approximation be specified for each band individually. We
turn it on for TT, EE, and BB, and turn it off for TE.
Next is a block for each polarization in the file. This contains the
name of the polarization, then one line containing the spectrum for
each band power in the polarization. The fields are:
1) Band #
2) Power spectrum (l(l+1)C_l/2pi, in uK^2)
3) and 4) - error bars.
5) noise spectrum, used in the offset-lognormal approximation.
6) and 7) the lower/upper ell range contained in the band
8) the iliketype flag for the band. 1 means use offset-lognormal, 0
means Gaussian.
Then a block containing the same-band correlations between
band-powers. Ones along the diagonal, with the off-diagonal terms the
degree of correlation between bands.
Finally, the Fisher matrix for the entire spectrum (all
polarizations). Units are in uK^4. This full matrix is used when
calculating the likelihood of a spectrum in COSMOMC.
There is also a directory "windows" - in it are the band-power window
functions. There is one file for each band. Columns are
1) ell
2)-5) W_ell/ell for each polarization. Columns are normalized, so
expected C_ell is sum(W_ell,PP')C_ell,PP' over ell and
polarizations PP'.
Last update: 2006-11-07
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