## The last tango before MAP

Here's a combination of all data as of December 2002 (incl. Acbar + new Boom) taking into account
calibration and beam errors (click on it for ps).
Curve shows best model fit for CMB+LSS data.

Here are text files with the corresponding
data,
window functions and
correlation matrix.
(These files and the plot above include the new Acbar and Boomerang (Ruhl et al MADCAP)
measurements. If you for some reason want the pre-Acbar results, here's the
data,
window functions and
correlation matrix.)
The window function file above contains 28 columns, giving the
window functions W_l for each of the 28 band power measurements with
the convention
*(dT)^2 = sum W_l (dT_l)^2 = sum l(l+1) W_l C_l/2 pi*.
Note that this differs from the traditional definition by a factor of l
- it's more approptiate to think of the band power as an average
on a linear plot rather than on a log-plot now that we're all plotting
small-scale CMB data with a linear l-axis.
Also, note that some of these window functions go slightly
negative, and that that's OK.
Note that the file gives not the covariance matrix but the dimensionless
correlation matrix *R*, which is related to the covariance matrix
*C* by
*C_ij = R_ij sigma_i sigma_j*.
To test a model against this data, put the first 2000 values
of dT_l^2 = l(l+1) C_l/2 pi into a vector c and compute
*chi2 = (q-Wc)^t C^{-1} (q-Wc)*,
where *q* is our vector of 28 data points and
*W* is our window matrix.
You'll find more data details and links here.
**Update with Acbar and ultimate BOOM coming hopefully later today (02/12/20).**
##
The last stand before MAP: cosmological parameters from lensing, CMB and galaxy clustering

Please click here to download
our paper.

Click if
you are interested in other research of mine.

###
Authors:

Xiaomin Wang,
Max Tegmark,
Bhuvnesh Jain,
Matias Zaldarriaga
###
Abstract:

Cosmic shear measurements have now improved to the point where they deserve to
be trea ted on par with CMB and galaxy clustering data for cosmological
parameter analysis, us ing the full measured aperture mass variance curve
rather than a mere phenomenological parametrization thereof. We perform a
detailed 9-parameter analysis of recent lensing (RCS), CMB (up to Archeops) and
galaxy clustering (2dF) data, both separately and joi ntly. CMB and 2dF data
are consistent with a simple flat adiabatic scale-invariant mod el with
Omega_Lambda=0.72+/-0.09, omega_cdm=0.115+/- 0.013, omega_b=0.0024+/-0.003, an
d a hint of reionization around z~8. Lensing helps further tighten these
constraints, but reveals tension regarding the power spectrum normalization:
including the RCS surv ey results raises sigma8 significantly and forces other
parameters to uncomfortable va lues. Indeed, sigma8 is emerging as the
currently most controversial cosmological para meter, and we discuss possible
resolutions of this sigma8 problem. We also comment on the disturbing fact that
most recent analyses (including this one) obtain error bars s maller than the
Fisher matrix bound. We produce a CMB power spectrum combining all exi sting
experiments, and using it for a "MAP versus world" comparison next month will
pr ovide a powerful test of how realistic the error estimates have been in the
cosmology community.
###
Reference info:

Submitted to *Phys. Rev. D*

Return to my home page

This page was last modified December 20, 2002.
max@physics.upenn.edu