Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-03-02
Mon.Not.Roy.Astron.Soc.368:226-246,2006
Astronomy and Astrophysics
Astrophysics
23 pages, 19 figures. Some new results added, including a new section about the role of foregrounds and instrumental noise. Ac
Scientific paper
10.1111/j.1365-2966.2006.10089.x
We present a study of the effect of component separation on the recovered cosmic microwave background (CMB) temperature distribution, considering Gaussian and non-Gaussian input CMB maps. First, we extract the CMB component from simulated Planck data (in small patches of the sky) using the maximum entropy method (MEM), Wiener filter (WF) and a method based on the subtraction of foreground templates plus a linear combination of frequency channels (LCFC). We then apply a wavelet-based method to study the Gaussianity of the recovered CMB and compare it with the same analysis for the input map. When the original CMB map is Gaussian (and assuming that point sources have been removed), we find that none of the methods introduce non-Gaussianity (NG) in the CMB reconstruction. On the contrary, if the input CMB map is non-Gaussian, all the studied methods produce a reconstructed CMB with lower detections of NG than the original map. This effect is mainly due to the presence of instrumental noise. In this case, MEM tends to produce slightly higher non-Gaussian detections in the reconstructed map than WF whereas the detections are lower for the LCFC. We have also studied the effect of point sources in the MEM reconstruction. If no attempt to remove point sources is performed, they clearly contaminate the CMB reconstruction, introducing spurious NG. When the brightest point sources are removed from the data using the Mexican Hat Wavelet, the Gaussian character of the CMB is preserved. However, when analysing larger regions of the sky, the variance of our estimators will be appreciably reduced and, in this case, we expect the point source residuals to introduce spurious NG in the CMB. Thus, a careful subtraction (or masking) of point source emission is crucial when studying the Gaussianity of the CMB.
Barreiro Belen R.
Hobson Michael P.
Martinez-Gonzalez Enrique
Vielva Patricio
No associations
LandOfFree
Effect of component separation on the temperature distribution of the CMB does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Effect of component separation on the temperature distribution of the CMB, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Effect of component separation on the temperature distribution of the CMB will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-284693