Evidence for a Galactic gamma ray halo
Abstract
We present quantitative statistical evidence for a -ray emission halo surrounding the Galaxy. Maps of the emission are derived. EGRET data were analyzed in a wavelet-based non-parametric hypothesis testing framework, using a model of expected diffuse (Galactic + isotropic) emission as a null hypothesis. The results show a statistically significant large scale halo surrounding the center of the Milky Way as seen from Earth. The halo flux at high latitudes is somewhat smaller than the isotropic gamma-ray flux at the same energy, though of the same order (O(10^(-7)--10^(-6)) ph/cm^2/s/sr above 1 GeV).
Keywords
Cite
@article{arxiv.astro-ph/9803237,
title = {Evidence for a Galactic gamma ray halo},
author = {D. D. Dixon and D. H. Hartmann and E. D. Kolaczyk and J. Samimi and R. Diehl and G. Kanbach and H. Mayer-Hasselwander and A. W. Strong},
journal= {arXiv preprint arXiv:astro-ph/9803237},
year = {2009}
}
Comments
Final version accepted for publication in New Astronomy. Some additional results/discussion included, along with entirely revised figures. 19 pages, 15 figures, AASTeX. Better quality figs (PS and JPEG) are available at http://tigre.ucr.edu/halo/paper.html