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The Determination of the Age of Globular Clusters: A Statistical Approach

Published online by Cambridge University Press:  03 August 2017

Miriam Rengel ,
Juan Mateu  and
Gustavo Bruzual
Miriam Rengel
Affiliation:
TLS Tautenburg, 07778 Tautenburg, Germany Centro de Investigaciones de Astronomía, Mérida 5101-A, Venezuela
Juan Mateu
Affiliation:
Centro de Investigaciones de Astronomía, Mérida 5101-A, Venezuela
Gustavo Bruzual
Affiliation:
Centro de Investigaciones de Astronomía, Mérida 5101-A, Venezuela

Abstract

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We present a statistical approach for determining the age of Globular Clusters (GCs) that allows estimating the age derived from CMDs more accurately than the conventional method of isochrone fitting. We measure how closely a set of synthetic CMDs constructed from different evolutionary models resemble the observed ones by determining the likelihood using Saha and χ2 statistics. The model which best matches the observational data, of a set of plausible ones, is the one with the highest value of the estimator. We apply this method to a set of three different evolutionary models presented by three different authors. Each of these sets consists again of many different models of various chemical abundances, ages, input physics and the like. We subsequently derive the age of GCs NGC 6397, M92 and M3. With a confidence level of 99%, we find that the best estimate of the age is 14.0 Gyrs within the range of 13.8 to 14.4 Gyrs for NGC 6397, 14.75 Gyrs within the range of 14.50 to 15.40 Gyrs for M92, and 16.0 Gyrs within the range of 15.9 to 16.3 Gyrs for M3.

Type
Part 4. Star Cluster Formation and Evolution: Theory and Observation
Information
Symposium - International Astronomical Union , Volume 207: Extragalactic Star Clusters , 2002 , pp. 716 - 718
Copyright
Copyright © Astronomical Society of the Pacific 2002 

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