Astro-ph communication: Simulations of the WMAP Internal Linear Combination sky map

Abstract

Following this astro-ph communication, we release a set of 10,000 WMAP ILC simulations, produced as described by Eriksen et al. (2004). We strongly encourage that an analysis of these simulations accompanies any scientific analysis of the observed ILC map, in order to assess the stability of the results. For examples of such analyses, we refer the reader to our original paper. In particular, Figure 1c) and d) show the bias and uncertainty induced by the ILC method, and Figure 7 shows a sobering examples of a low-l analysis; the reconstructed quadrupole-octopole alignment is plotted against the true input alignment, and the correlation is underwhelming. It can hardly be emphasized too strongly -- the heavily processed full-sky WMAP maps are not reliable for quantitative analysis, neither at large nor small scales, and they should only, at best, be used as supportive evidence. We hope that these simulations will reduce some of the confusion regarding these maps that currently exists in the community.