The Panchromatic Hubble Andromeda Treasury. III. Measuring Ages and Masses of Partially Resolved Stellar Clusters
Creators
- Beerman, Lori C.1
- Johnson, L. Clifton1
- Fouesneau, Morgan1
- Dalcanton, Julianne J.1
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Weisz, Daniel R.1
- Seth, Anil C.2
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Williams, Ben F.1
- Bell, Eric F.3
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Bianchi, Luciana C.4
- Caldwell, Nelson5
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Dolphin, Andrew E.
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Gouliermis, Dimitrios A.6, 7
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Kalirai, Jason S.8
- Larsen, Søren S.9
- Melbourne, Jason L.10
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Rix, Hans-Walter7
- Skillman, Evan D.11
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1.
University of Washington
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2.
University of Utah
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3.
University of Michigan–Ann Arbor
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4.
Johns Hopkins University
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5.
Harvard-Smithsonian Center for Astrophysics
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6.
Heidelberg University
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7.
Max Planck Institute for Astronomy
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8.
Space Telescope Science Institute
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9.
Radboud University Nijmegen
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10.
California Institute of Technology
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11.
University of Minnesota
Abstract
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.
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.Attached Files
Published - 0004-637X_760_2_104.pdf
Files
0004-637X_760_2_104.pdf
Additional details
Identifiers
- Eprint ID
- 36051
- Resolver ID
- CaltechAUTHORS:20121219-114553182
Funding
- NASA
- HST-GO-12055
- NASA
- NAS5-26555
- Deutsche Forschungsgemeinschaft (DFG)
- GO 1659/3-1
Dates
- Created
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2012-12-19Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field