0.25 keV contours from M101
Image credit: Snowden & Pietsch 1995, ApJ, 452, 627.
The 1/4 keV X-ray contours superposed onto a digitized version of a blue photograph of M101 from the Atlas of Peculiar Galaxies (Arp 1966). The X-ray data have been smoothed with a Gaussian function of 42" FWHM. Contours are given for 2,3,4,5,7,9,11,13,17 sigma level above background (one sigma corresponds to 220 x 10^-6 counts/s/arcmin^2). The extensive 1/4 keV emission most likely originates in a hot plasma in the halo of M101 raising numerous questions such as what is the origin of the plasma (most likely energetic activity in the galactic disk) and how did it get to the halo (perhaps "chimneys" or "fountains"). As M101 is similar in type to the Milky Way, it can give us insight into the dynamics of our own Galaxy.
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