2003/01/29 by Elena Pierpaoli, E. Pierpaoli · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Cosmology and Gravitation Theories #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1086/374410
published as Astrophys.J. 589 (2003) 58-66 · 21 pages, 8 figures. Submitted to ApJ
arxiv created 2003/01/29 · openalex publication_date 2003/05/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We discuss point-source foregrounds for the Wilkinson Microwave Anisotropy Probe ( WMAP ) experiment. We consider several possible strategies for removing them and we assess how the statistics of the cosmic microwave background (CMB) signal are affected by the residual sources. Assuming a power-law distribution for the point sources, we propose a method aimed at determining the slope of the distribution from the analysis of the moments of the observed maps. The same method allows for a determination of the underlying CMB variance. We conclude that the best strategy for finding point sources is the simultaneous thresholding of the filtered map at all frequencies, with a relatively low threshold. With this strategy, we expect to find 70% (95%) of the sources above 3 (4) σ. Assuming the most conservative case for point-source detection, the recovered slope of the point-source distribution is 2.55 ± 0.15, for a fiducial n = 2.5 value. The recovered CMB plus noise map variance is within 0.2% from the real one, with a standard deviation of 0.31%, while cosmic variance contributes 2.2% to the same CMB plus noise map.