Cross-Correlation analysis of WMAP and EGRET in Wavelet Space

摘要

We cross correlate the Wilkinson Microwave Anisotropy Probe (WMAP) first yeardata and the diffuse gamma-ray intensity maps from the Energetic Gamma RayExperiment Telescope (EGRET) using spherical wavelet approaches. Correlationsat 99.7% significance level have been detected, at scales around $15^{circ}$in the WMAP foreground cleaned W-band and Q-band maps, based on data fromregions that are outside the most conservative WMAP foreground mask; nosignificant correlation is found with the Tegmark cleaned map. The detectedcorrelation is most likely of Galactic origin, and thus can help us probing theorigins of possible Galactic foreground residuals and ultimately removing themfrom measured microwave sky maps.