22 research outputs found
Can residuals of the Solar system foreground explain low multipole anomalies of the CMB ?
The low multipole anomalies of the Cosmic Microwave Background has received
much attention during the last few years. It is still not ascertained whether
these anomalies are indeed primordial or the result of systematics or
foregrounds. An example of a foreground, which could generate some non-Gaussian
and statistically anisotropic features at low multipole range, is the very
symmetric Kuiper Belt in the outer solar system. In this paper, expanding upon
the methods presented by Maris et al. (2011), we investigate the contributions
from the Kuiper Belt objects (KBO) to the WMAP ILC 7 map, whereby we can
minimize the contrast in power between even and odd multipoles in the CMB,
discussed discussed by Kim & Naselsky (2010). We submit our KBO de-correlated
CMB signal to several tests, to analyze its validity, and find that
incorporation of the KBO emission can decrease the quadrupole-octupole
alignment and parity asymmetry problems, provided that the KBO signals has a
non-cosmological dipole modulation, associated with the statistical anisotropy
of the ILC 7 map. Additionally, we show that the amplitude of the dipole
modulation, within a 2 sigma interval, is in agreement with the corresponding
amplitudes, discussed by Lew (2008).Comment: 24 pages, 9 figures, 5 tables. Matches version in JCA
Antimatter from the cosmological baryogenesis and the anisotropies and polarization of the CMB radiation
We discuss the hypotheses that cosmological baryon asymmetry and entropy were
produced in the early Universe by phase transition of the scalar fields in the
framework of spontaneous baryogenesis scenario. We show that annihilation of
the matter-antimatter clouds during the cosmological hydrogen recombination
could distort of the CMB anisotropies and polarization by delay of the
recombination. After recombination the annihilation of the antibaryonic clouds
(ABC) and baryonic matter can produce peak-like reionization at the high
redshifts before formation of quasars and early galaxy formation. We discuss
the constraints on the parameters of spontaneous baryogenesis scenario by the
recent WMAP CMB anisotropy and polarization data and on possible manifestation
of the antimatter clouds in the upcoming PLANCK data.Comment: PRD in press with minor change
Topological Defects in Gravitational Lensing Shear Fields
Shear fields due to weak gravitational lensing have characteristic coherent
patterns. We describe the topological defects in shear fields in terms of the
curvature of the surface described by the lensing potential. A simple
interpretation of the characteristic defects is given in terms of the the
umbilical points of the potential surface produced by ellipsoidal halos. We
show simulated lensing shear maps and point out the typical defect
configurations. Finally, we show how statistical properties such as the
abundance of defects can be expressed in terms of the correlation function of
the lensing potential.Comment: 17 pages, 4 figure
The Cold Spot as a Large Void: Lensing Effect on CMB Two and Three Point Correlation Functions
The "Cold Spot" in the CMB sky could be due to the presence of an anomalous
huge spherical underdense region - a "Void" - of a few hundreds Mpc/h radius.
Such a structure would have an impact on the CMB two-point (power spectrum) and
three-point (bispectrum) correlation functions not only at low-l, but also at
high-l through Lensing, which is a unique signature of a Void. Modeling such an
underdensity with an LTB metric, we show that for the power spectrum the effect
should be visible already in the WMAP data only if the Void radius is at least
L \gtrsim 1 Gpc/h, while it will be visible by the Planck satellite if L
\gtrsim 500 Mpc/h. We also speculate that this could be linked to the high-l
detection of an hemispherical power asymmetry in the sky. Moreover, there
should be non-zero correlations in the non-diagonal two-point function. For the
bispectrum, the effect becomes important for squeezed triangles with two very
high l's: this signal can be detected by Planck if the Void radius is at least
L \gtrsim 300 Mpc/h, while higher resolution experiments should be able to
probe the entire parameter space. We have also estimated the contamination of
the primordial non-Gaussianity f_NL due to this signal, which turns out to be
negligible.Comment: v1: 18 pages, 12 figures; v2: 19 pages, 12 figures, calculation of
bispectrum improved, reference added, published version; v3: 19 pages, 12
figures, refined eq.(9) and related figures, conclusions strengthene