THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. III. MEASURING AGES AND MASSES OF PARTIALLY RESOLVED STELLAR CLUSTERS

Journal Article · Sat Dec 01 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/760/2/104· OSTI ID:22086256

Beerman, Lori C; Johnson, L Clifton; Fouesneau, Morgan; Dalcanton, Julianne J; Weisz, Daniel R; Williams, Ben F ^[1]; Seth, Anil C ^[2]; Bell, Eric F ^[3]; Bianchi, Luciana C ^[4]; Caldwell, Nelson ^[5]; Dolphin, Andrew E ^[6]; Gouliermis, Dimitrios A ^[7]; Kalirai, Jason S ^[8]; Larsen, Soren S ^[9]; Melbourne, Jason L ^[10]; Rix, Hans-Walter ^[11]

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1. Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)
2. Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States)
3. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)
4. Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
5. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
6. Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States)
7. Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany)
8. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
9. Department of Astrophysics, IMAPP, Radboud University Nijmegen, P.O. Box 9010, NL-6500 GL Nijmegen (Netherlands)
10. Caltech Optical Observatories, Division of Physics, Mathematics and Astronomy, Mail Stop 301-17, California Institute of Technology, Pasadena, CA 91125 (United States)
11. Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)

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 ({approx}<10{sup 4} M {sub Sun }). 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.

• OSTI ID: 22086256
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 760; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
COLOR
COMPUTERIZED SIMULATION
GALAXIES
MASS
STAR CLUSTERS
STARS
STOCHASTIC PROCESSES
VISIBLE RADIATION