No evidence for mass segregation in massive young clusters

TL;DR

This study questions the reliability of common indicators used to detect mass segregation in young stellar clusters, highlighting the impact of observational incompleteness and suggesting no current evidence supports mass segregation in such clusters.

Contribution

The paper demonstrates that traditional mass segregation indicators are highly sensitive to sample incompleteness, challenging previous claims of mass segregation in young clusters.

Findings

Indicators are sensitive to sample incompleteness

Radial completeness corrections are inadequate

No robust evidence of mass segregation in young clusters

Abstract

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 (10^4 Msun) 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.