A Caltech Library Service

The Panchromatic Hubble Andromeda Treasury. III. Measuring Ages and Masses of Partially Resolved Stellar Clusters

Beerman, Lori C. and Johnson, L. Clifton and Fouesneau, Morgan and Dalcanton, Julianne J. and Weisz, Daniel R. and Seth, Anil C. and Williams, Ben F. and Bell, Eric F. and Bianchi, Luciana C. and Caldwell, Nelson and Dolphin, Andrew E. and Gouliermis, Dimitrios A. and Kalirai, Jason S. and Larsen, Søren S. and Melbourne, Jason L. and Rix, Hans-Walter and Skillman, Evan D. (2012) The Panchromatic Hubble Andromeda Treasury. III. Measuring Ages and Masses of Partially Resolved Stellar Clusters. Astrophysical Journal, 760 (2). Art. No. 104. ISSN 0004-637X.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


The apparent age and mass of a stellar cluster can be strongly affected by stochastic sampling of the stellar initial mass function (IMF), when inferred from the integrated color of low-mass clusters (≾10^4 M_☉). We use simulated star clusters to show that these effects are minimized when the brightest, rapidly evolving stars in a cluster can be resolved, and the light of the fainter, more numerous unresolved stars can be analyzed separately. When comparing the light from the less luminous cluster members to models of unresolved light, more accurate age estimates can be obtained than when analyzing the integrated light from the entire cluster under the assumption that the IMF is fully populated. We show the success of this technique first using simulated clusters, and then with a stellar cluster in M31. This method represents one way of accounting for the discrete, stochastic sampling of the stellar IMF in less massive clusters and can be leveraged in studies of clusters throughout the Local Group and other nearby galaxies.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Weisz, Daniel R.0000-0002-6442-6030
Williams, Ben F.0000-0002-7502-0597
Bianchi, Luciana C.0000-0001-7746-5461
Dolphin, Andrew E.0000-0001-8416-4093
Gouliermis, Dimitrios A.0000-0002-2763-0075
Kalirai, Jason S.0000-0001-9690-4159
Rix, Hans-Walter0000-0003-4996-9069
Additional Information:© 2012 American Astronomical Society. Received 2012 July 12; accepted 2012 September 21; published 2012 November 9. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. The authors acknowledge the collective efforts of the entire PHAT team in this project. This research made extensive use of NASA’s Astrophysics Data System Bibliographic Services. Support for this work was provided by NASA through grant number HST-GO-12055 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. D.A.G. gratefully acknowledges support by the German Research Foundation (DFG) through grant GO 1659/3-1. Also, the authors thank the anonymous referee for a prompt and useful report.
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)GO 1659/3-1
Subject Keywords:galaxies: stellar content
Issue or Number:2
Record Number:CaltechAUTHORS:20121219-114553182
Persistent URL:
Official Citation:The Panchromatic Hubble Andromeda Treasury. III. Measuring Ages and Masses of Partially Resolved Stellar Clusters Lori C. Beerman, L. Clifton Johnson, Morgan Fouesneau, Julianne J. Dalcanton, Daniel R. Weisz, Anil C. Seth, Ben F. Williams, Eric F. Bell, Luciana C. Bianchi, Nelson Caldwell, Andrew E. Dolphin, Dimitrios A. Gouliermis, Jason S. Kalirai, Søren S. Larsen, Jason L. Melbourne, Hans-Walter Rix, and Evan D. Skillman doi:10.1088/0004-637X/760/2/104
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36051
Deposited By: Ruth Sustaita
Deposited On:19 Dec 2012 21:06
Last Modified:09 Mar 2020 13:19

Repository Staff Only: item control page