To do this kind of analysis we have to analyze 9 all-sky maps at full Planck resolution (aprox. 200 MB each). Then, we have to divide each one of these maps into 373 projected patches (512x512 pixels in size), this makes a total of 3357 patches (it would take 18 hours to run in a single CPU). Once we have the patches written to disk, we apply the MMF algorithm to the data. The analysis of each set of nine patches centered in the same region of the sky takes between 3 to 35 minutes, depending on the number of iterations. In our case, we want to estimate the size of the clusters properly, and, therefore, the analysis lasts aprox. 35 minutes per region. Since there are 373 regions to be analyzed, it would take about 266 hours to do this analysis (aproximately 10 days in single CPU). We have done this analysis in 13 hours using 20 working nodes.
4. Conclusions / Future plans
This analysis using multifrequency maps required 13 hours of CPU time in each of the 20 planck vo working nodes and aprox. 20GB of space at IFCA, 18 GB of which were the input patches to be analysed. The output of the analysis is a list of detected clusters (just a few KB's) and 373 combined maps , one per region, where the detection is performed (2 GB). In the future a version of the Planck Sky Model introducing the satellite systematics will be released and this analysis will be repeated.
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Astronomy. Cosmology, Planck. Detection of SZ Clusters Galaxies.
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1. Short overview
In 2008 ESA's Planck satellite will be launch. The main objective of this mission is to produce a map of the anisotropies of the Cosmic Microwave Background radiation (CMB), a relic radiation from the Big Bang. To study this map, the compact source emission from distant galaxies and clusters of galaxies must be detected and extracted. We report on the work done detecting SZ clusters in realistic simulations of Planck.