1.8 MeV Gamma-rays from the Vela Region


COMPTEL imaging of the sky at 1.8 MeV resulted in the detection of prominent emission from the Vela region. Early suggestions of the bulk of this excess being associated with the Vela supernova remnant itself were mainly based on plausible candidate sources in this region. Meanwhile, all-sky analysis of COMPTEL 1.8 MeV data demonstrated that massive stars and core collapse supernovae are the predominant source of 26Al radioactivity in the Galaxy. With the improved database from over six years of observations, and in particular more recent exposures of the Vela region, one can now better distinguish between source hypotheses. We present the improved 1.8 MeV emission map of this region, and analyze the observed emission in terms of different models with localized and large-scale components. We discuss the implications for nearby supernova remnants (Vela XYZ and the new ROSAT/COMPTEL SNR), the constraints on 26Al yields for the Wolf Rayet star in γ²V el (the nearest member of this class of stars), and for nearby associations of massive stars.

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Journal Title

Astrophysical Letters & Communications


Taylor & Francis

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c 1999 OSA