Nayantara Gupta, Biman B. Nath, Peter L. Biermann, Eun -Suk Seo, Todor Stanev, Julia Becker Tjus
The spectrum observed by Fermi-LAT from the Galactic centre region shows a gamma ray feature near 130 GeV, that in some analyses appears as a possible line. We discuss the possibility that this gamma ray feature has a cosmic ray origin. We argue that the cosmic ray electrons steepen near 1 TeV from $E^{-3}$ to about $E^{-4.2}$, and are all secondary derived from the knee-feature of normal cosmic rays. We argue that the observed feature at $\sim 130$ GeV could essentially be a noise feature on top of a sharp turn-off in the $\gamma$ ray spectrum at $\sim 130$ GeV. This match suggests that the knee of normal cosmic rays is the same everywhere in the Galaxy. We suggest that it follows that all supernovae contributing give the same cosmic ray spectrum, with the knee feature given by common stellar properties; in fact, this is consistent with the supernova theory proposed by Bisnovatyi-Kogan (1970), a magneto-rotational mechanism: Massive stars converge to common properties in terms of rotation and magnetic fields just before they explode.
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http://arxiv.org/abs/1301.4405
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