3 research outputs found
Reionization by active sources and its effects on the cosmic microwave background
We investigate the possible effects of reionization by active sources on the
cosmic microwave background. We concentrate on the sources themselves as the
origin of reionization, rather than early object formation, introducing an
extra period of heating motivated by the active character of the perturbations.
Using reasonable parameters, this leads to four possibilities depending on the
time and duration of the energy input: delayed last scattering, double last
scattering, shifted last scattering and total reionization. We show that these
possibilities are only very weakly constrained by the limits on spectral
distortions from the COBE FIRAS measurements. We illustrate the effects of
these reionization possibilities on the angular power spectrum of temperature
anisotropies and polarization for simple passive isocurvature models and simple
coherent sources, observing the difference between passive and active models.
Finally, we comment on the implications of this work for more realistic active
sources, such as causal white noise and topological defect models. We show for
these models that non-standard ionization histories can shift the peak in the
CMB power to larger angular scales.Comment: 21 pages LaTeX with 11 eps figures; replaced with final version
accepted for publication in Phys. Rev.
Statistics of WMAP ILC map temperature fluctuations towards distant radio galaxies
For 2442 galaxies of the catalog, compiled based on the NED, SDSS, and CATS
survey data with redshifts z, > 0.3 we conducted an analysis of the amplitude
of temperature fluctuations in the cosmic microwave background (CMB) in the
points, corresponding to the direction to these objects. To this end, we used
the ILC map from the WMAP mission seven-year data release. We have estimated
the dipole component of the background and tested the hypothesis of Kashlinsky
on the existence of a "dark bulk flow", determined for the estimated dipole
component of the CMB WMAP by the value of the CMB anisotropy in the direction
to the clusters of galaxies. We show that the amplitude of this dipole T max =
0.012mK is located within the {\sigma} interval, estimated by Monte Carlo
simulations for the Gaussian fluctuations of the CMB signal in the {\Lambda}CDM
model. The low amplitude of the dipole indicates that it is impossible to
confirm this hypothesis from the WMAP data. In addition, we studied the
statistics of the fluctuation amplitude of the microwave signal in the
direction to radio galaxies. A weakening of the absolute value of the mean
signal in the corresponding fields was discovered.Comment: 7 pages,4 figures,1 tabl