Non-linear Data Analysis on the Sphere by Gregor Rossmanith

Author:Gregor Rossmanith
Language: eng
Format: epub
Publisher: Springer International Publishing, Heidelberg

4.2 WMAP Data and Simulations

For our investigations we use the Q-, V- and W-band five-year-data of the WMAP-satellite as it is provided by the WMAP-Team.1 We work with the foreground-reduced maps, which use the Foreground Template Model proposed in [53] and [54] for foreground reduction. To obtain a co-added VW-map as well as single V-, W- and Q-maps, we accumulate the differencing assemblies Q1, Q2, V1, V2, W1, W2, W3, W4 via a noise-weighted sum [55]:

(4.1)

In this equation, characterises the set of required assemblies, e.g. for the co-added VW-map . The parameters and correspond to the co-latitude and the longitude on the sphere, while the five-year noise per observation of the different assemblies, given by [56], is denoted by .

We decrease the resolution of the maps to 786432 pixels, which equals to in the employed HEALPix-software2 [57] and cut out the heavily foreground-affected parts of the sky using the KQ75-mask [58], which has to be downgraded as well. We choose a conservative downgrading of the mask by taking only all pixels at that do completely consist of non-mask-pixels at . All downgraded pixels at , for which one or more pixels at belonged to the KQ75-mask, are considered to be part of the downgraded mask as well. In doing so, 28.4 % of the sky is removed (see upper left part of Fig. 4.1). Finally, we remove the residual monopol and dipol by means of the appropriate HEALPix routine applied to the unmasked pixels only.

Fig. 4.1The two plots on the left hand side illustrate the original 5-year WMAP-map of the co-added VW-band (above) and the related colour-coded -response (below). The equivalent plots for the mask-filling technique are arranged on the right hand side. These maps (and all following ones) are shown in a conventional scheme, namely the Mollweide projection in the Galactic reference frame with the Galactic Centre at the centre of the image and the longitude increasing from there to the left-hand side

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.