Statistics of WMAP ILC map temperature fluctuations towards distant radio galaxies

TL;DR

This study analyzes WMAP ILC map temperature fluctuations towards distant radio galaxies, estimating the dipole component and testing the dark bulk flow hypothesis, finding no significant evidence for it and observing a weakening of microwave signal fluctuations.

Contribution

It provides the first statistical analysis of CMB temperature fluctuations towards distant radio galaxies using WMAP data, testing the dark bulk flow hypothesis.

Findings

Dipole amplitude within expected Gaussian fluctuation range.

No confirmation of the dark bulk flow hypothesis.

Observed weakening of microwave signal fluctuations towards radio galaxies.

Abstract

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.