The mass-to-light ratio of rich star clusters - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




The mass-to-light ratio of rich star clusters - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We point out a strong time-evolution of the mass-to-light conversion factoreta commonly used to estimate masses of unresolved star clusters from observedcluster spectro-photometric measures. We present a series of gas-dynamicalmodels coupled with the Cambridge stellar evolution tracks to computeline-of-sight velocity dispersions and half-light radii weighted by theluminosity. We explore a range of initial conditions, varying in turn thecluster mass and-or density, and the stellar population-s IMF. We find thateta, and hence the estimated cluster mass, may increase by factors as large as3 over time-scales of 50 million years. We apply these results to an hypotheticcluster mass distribution function d.f. and show that the d.f. shape may bestrongly affected at the low-mass end by this effect. Fitting truncatedisothermal Michie-King models to the projected light profile leads toover-estimates of the concentration parameter c of delta c ~ 0.3 compared tothe same functional fit applied to the projected mass density.



Author: Christian M. Boily, Jean-Julien Fleck, Ariane Lançon, Florent Renaud

Source: https://arxiv.org/







Related documents