Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Directional Variations of the Non-Gaussianity Parameter f_NL   We investigate local variations of the primordial non-Gaussianity parameter
f_NL in the WMAP data, looking for possible influence of foreground
contamination in the full-sky estimate of f_NL. We first improve the needlet
bispectrum estimate in (Rudjord et al. 2009) on the full-sky to f_NL= 73 +/- 31
using the KQ75 mask on the co-added V+W channel. We find no particular values
of f_NL estimates close to the galactic plane and conclude that foregrounds are
unlikely to affect the estimate of f_NL in the V and W bands even for the
smaller KQ85 mask. In the Q band however, we find unexpectedly high values of
f_NL in local estimates close to the galactic mask, as well as significant
discrepancies between Q band estimates and V/W band estimates. We therefore
conclude that the Q band is too contaminated to be used for non-Gaussianity
studies even with the larger KQ75 mask. We further noted that the local f_NL
estimates on the V+W channel are positive on all equatorial bands from the
north to the south pole. The probability for this to happen in a universe with
f_NL = 0 is less than one percent.

16
The categories of this paper are: stat
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th