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Centro de Astrofísica da Universidade do Porto

No evidence of mass segregation in massive young clusters

J. Ascenso, J. Alves, M. T. V. T. Lago

Aims. We investigate the validity of the mass segregation indicators commonly used in analysing young stellar clusters.
Methods. We simulate observations by constructing synthetic seeing-limited images of a 1000 massive clusters (104 Msolar) with a standard IMF and a King-density distribution function.
Results. We find that commonly used indicators are highly sensitive to sample incompleteness in observational data and that radial completeness determinations do not provide satisfactory corrections, rendering the studies of radial properties highly uncertain. On the other hand, we find that, under certain conditions, the global completeness can be estimated accurately, allowing for the correction of the global luminosity and mass functions of the cluster.
Conclusions. We argue that there is currently no observational evidence of mass segregation in young compact clusters since there is no robust way to differentiate between true mass segregation and sample incompleteness effects. Caution should then be exercised when interpreting results from observations as evidence of mass segregation.

Astronomy and Astrophysics
Volume 495, Page 147
February 2009

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