Bibcode
Plüschke, S.; Cerviño, M.; Diehl, R.; Kretschmer, K.; Hartmann, D. H.; Knödlseder, J.
Referencia bibliográfica
27th International Cosmic Ray Conference. Invited, Rapporteur, and Highlight Papers. 07-15 August, 2001. Hamburg, Germany. Under the auspices of the International Union of Pure and Applied Physics (IUPAP). Edited by R. Schlickeiser., p.297-300
Fecha de publicación:
2001
Número de citas
3
Número de citas referidas
1
Descripción
The COMPTEL observations of the diffuse galactic 1.809 MeV emission
attributed to the radioactive decay of 26 Al have confirmed the diffuse
nature of this interstellar emission line. One of the most significant
features of the reconstructed intensity pattern is a flux enhancement in
the direction of the Cygnus region. This region is fairly young and
contains a wealth of massive stars, most of them grouped in the Cygnus
OB associations. Multi-frequency model fitting strongly supports the
hypothesis of massive stars and their descendent supernovae being the
dominant sources of interstellar 26 Al as observed by COMPTEL. Massive
stars and supernovae are known to impart a large amount of kinetic
energy into the surrounding ISM which lead to shockregions and large
cavities. In addition, a large fraction of the electro-magnetic
radiation of massive stars lies in the extreme ultra-violet causing
photoionisation of the surrounding interstellar medium. We applied a
population synthesis model in combination with an analytic model of the
expansion of superbubbles to the Cygnus OB associations. The model
predicts the expected 1.809 MeV flux and the γ-ray line intensity
due to interstellar 60 Fe. We compute the sizes and expansion parameters
of the expected HI-structures and the free-free emission intensities due
to the photoionizing radiation from massive stars within this region of
the sky. We discuss our present understanding of the Cygnus region with
respect to the massive star census and history. Our model assigns about
70% of the 1.809 MeV intensity to six known OB associations, about 20%
to known isolated sources and roughly 10% to an unkown diffuse
component.