Abstract. The morphology and stellar content of 22 clusters in the Cygnus area has been determined using 2MASS infrared observations in the J and K bands. 7 of the clusters are well-known objects and our results are in good agreement with previous work. 12 objects are recently-discovered cluster candidates (Dutra & Bica 2001) and 3 are new cluster candidates. Adopting distance estimates from the literature or by considering cluster counterparts, we derive a consistent set of parameters suitable for analysis and comparison: center coordinates, radius, stellar population, IMF slope and mass range. We find a mean IMF slope of Γ = −1.30 for the known clusters and Γ = −1.40 for the others. Infrared data having better completeness, we derive larger stellar contents and cluster masses than previous works. An important fraction of the cluster stellar population in Cygnus is hidden in very obscured areas. A clear tendency towards mass segregation appears for most of the clusters. Some of the new clusters seem to be quite massive, probably hosting very massive stars at the center. They are privileged targets for more detailed investigations using infrared spectroscopy.

Abstract. Gamma-ray and microwave observations of the Cygnus region reveal an intense signal of 1.809 MeV line emission, attributed to radioactive decay of 26 Al, that is closely correlated with 53 GHz free-free emission, originating from the ionised interstellar medium. We modelled both emissions using a multi-wavelength evolutionary synthesis code for massive star associations that we applied to the known massive star populations in Cygnus. For all OB associations and young open clusters in the field, we determined the population age, distance, and richness as well as the uncertainties in all these quantities from published photometric and spectroscopic data. We propagate the population uncertainties in model uncertainties by means of a Bayesian method. The young globular cluster Cyg OB2 turns out to be the dominant 26 Al nucleosynthesis and ionisation source in Cygnus. Our model reproduces the ionising luminosity of the Cygnus region very well, yet it underestimates 26 Al production by about a factor of 2. We attribute this underestimation to shortcomings of current nucleosynthesis models, and suggest the inclusion of stellar rotation as possible mechanism to enhance 26 Al production. We also modelled 60 Fe nucleosynthesis in the Cygnus region, yet the small number of recent supernova events suggests only little 60 Fe production. Consequently, a detection of the 1.137 MeV and 1.332 MeV decay lines of 60 Fe from Cygnus by the upcoming INTEGRAL observatory is not expected.

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