Masking versus removing point sources in CMB data: the source corrected WMAP power spectrum from new extended catalogue

TL;DR

This study compares masking and removing point sources in WMAP data to assess their impact on the CMB power spectrum, finding consistent results and providing publicly available cleaned maps and masks.

Contribution

It introduces an extended point source catalogue and compares different source removal methods, demonstrating their effects on the CMB power spectrum analysis.

Findings

Point source removal does not bias the CMB spectrum.

Masked and cleaned maps yield consistent power spectra.

Publicly available maps and masks facilitate future analyses.

Abstract

In (Scodeller et al.) a new and extended point source catalogue obtained from the WMAP 7-year data was presented. It includes most of the sources included in the standard WMAP 7-year point source catalogues as well as a large number of new detections. Here we study the effects on the estimated CMB power spectrum when taking the newly detected point sources into consideration. We create point source masks for all the 2102 sources that we detected as well as a smaller one for the 665 sources detected in the Q, V and W bands. We also create WMAP7 maps with point sources subtracted in order to compare with the spectrum obtained with source masks. The extended point source masks and point source cleaned WMAP7 maps are made publicly available. Using the proper residual correction, we find that the CMB power spectrum obtained from the point source cleaned map without any source mask is fully consistent with the spectrum obtained from the masked map. We further find that the spectrum obtained masking all 2102 sources is consistent with the results obtained using the standard WMAP 7-year point source mask (KQ85y7). We also verify that the removal of point sources does not introduce any skewness.