Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exact likelihood evaluations and foreground marginalization in low
  resolution WMAP data   The existing analysis of WMAP data is based on approximations for the
likelihood function, which is likely to be inaccurate on large scales. Here we
present exact evaluations of the likelihood of the low multipoles by direct
inversion of the theoretical covariance matrix for low resolution WMAP maps. We
project out the unwanted galactic contaminants rather than subtract them, which
can remove some of the cosmological signal and may lead to a suppression of
power. We find an increase in power at low multipoles. For the quadrupole the
maximum likelihood values are rather uncertain and vary between 140-220\muK^2.
On the other hand, the probability distribution away from the peak is robust
and, assuming a uniform prior between 0 an 2000\muK^2, the probability of
having the true value above 1200\muK^2 (as predicted by the simplest Lambda CDM
model) is 10%, a factor of 2.5 higher than predicted by WMAP likelihood code.
We develop a fast likelihood evaluation routine that can be used instead of
WMAP routines for low l values. We apply it to the MCMC analysis to compare the
cosmological parameters between the two cases. The new analysis of WMAP either
alone or jointly with SDSS and VSA reduces the reported 2-sigma evidence for
running to less than 1-sigma, giving \alpha_s=-0.022\pm 0.033 for the combined
case. The new analysis prefers about 1-sigma lower value of Omega_m, a
consequence of an increased ISW contribution required by the increase in the
spectrum at low l. These results suggest that the details of foreground removal
and full likelihood analysis are important for the parameter estimation from
WMAP data and these methods should be particularly useful in the analysis of
polarisation, where foreground contamination may be much more severe.

15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
2
The categories of this paper are: math