Assaf Ben-David, Ely D. Kovetz, Nissan Itzhaki
We search for a direction in the sky that exhibits parity symmetry under
reflections through a plane. We use the natural estimator, which compares the
power in even and odd $\ell+m$ multipoles, and apply minimal blind masking of
outliers to the ILC map in order to avoid large errors in the reconstruction of
multipoles. The multipoles of the cut sky are calculated both naively and by
using the covariance inversion method and we estimate the significance of our
results using $\Lambda$CDM simulations. Focusing on low multipoles, $2\leq \ell
\leq \ell_{\max}$ with $\ell_{\max}=5,6$ or even 7, we find two perpendicular
directions of even and odd parity in the map. While the even parity direction
does not appear significant, the odd direction is quite significant -- at least
a $3.6\sigma$ effect.
View original:
http://arxiv.org/abs/1108.1702
No comments:
Post a Comment