Full Sky Study of Diffuse Galactic Emission at Decimeter Wavelengths

摘要

A detailed knowledge of the Galactic radio continuum is of high interest forstudies of the dynamics and structure of the Galaxy as well as for the problemof foreground removal in Cosmic Microwave Background measurements. In this workwe present a full-sky study of the diffuse Galactic emission at frequencies offew GHz, where synchrotron radiation is by far the dominant component. Weperform a detailed combined analysis of the extended surveys at 408, 1420 and2326 MHz (by Haslam et al. 1982, Reich 1982, Reich & Reich, 1986 and Jonas etal. 1998, respectively). Using the technique applied by Schlegel et al. (1998)to the IRAS data, we produce destriped versions of the three maps. This allowsus to construct a nearly-full-sky map of the spectral index and of thenormalization factor with sub-degree angular resolution. The resultingdistribution of the spectral indices has an average of beta = 2.695 anddispersion sigma_{beta} = 0.120. This is representative for the Galacticdiffuse synchrotron emission, with only minor effects from free-free emissionand point sources.