682 research outputs found
Signature of excess radio background in the 21-cm global signal and power spectrum
For abstract see published article
How Sensitive is the CMB to a Single Lens?
We study the imprints of a single lens, that breaks statistical isotropy, on
the CMB and calculate the signal to noise ratio (S/N) for its detection. We
emphasize the role of non-Gaussianities induced by LCDM weak lensing in this
calculation and show that typically the S/N is much smaller than expected. In
particular we find that the hypothesis that a void (texture) is responsible for
the WMAP cold spot can barely (cannot) be tested via weak lensing of the CMB.Comment: Accepted for publication in JCAP, 24 pages, 5 figure
Parity in the CMB: Space Oddity
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 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 CDM simulations. Focusing on low multipoles, with 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 effect.Comment: 6 pages, 7 figures. Accepted for publication in The Astrophysical
Journa
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