THE LUMINOSITY, MASS, AND AGE DISTRIBUTIONS OF COMPACT STAR CLUSTERS IN M83 BASED ON HUBBLE SPACE TELESCOPE/WIDE FIELD CAMERA 3 OBSERVATIONS
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States)
- Space Telescope Science Institute, Baltimore, MD (United States)
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States)
- Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
- NOAO, Tucson, AZ 85726-6732 (United States)
- Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)
- Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States)
- Institute of Astronomy, ETH-Zurich, 8093 Zurich (Switzerland)
- Department of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom)
- Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia)
- AURA, Washington, DC 20005 (United States)
- Institute for Astronomy, Honolulu, HI 96822 (United States)
- New Mexico State University, Las Cruces, NM 88003 (United States)
- Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Carnegie Institute of Washington, Pasadena, CA 91101-1292 (United States)
- ESTEC, Noordwijk, AG NL-2200 (Netherlands)
- Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom)
The newly installed Wide Field Camera 3 (WFC3) on the Hubble Space Telescope has been used to obtain multi-band images of the nearby spiral galaxy M83. These new observations are the deepest and highest resolution images ever taken of a grand-design spiral, particularly in the near-ultraviolet, and allow us to better differentiate compact star clusters from individual stars and to measure the luminosities of even faint clusters in the U band. We find that the luminosity function (LF) for clusters outside of the very crowded starburst nucleus can be approximated by a power law, dN/dL {proportional_to} L {sup {alpha}}, with {alpha} = -2.04 {+-} 0.08, down to M{sub V} {approx} -5.5. We test the sensitivity of the LF to different selection techniques, filters, binning, and aperture correction determinations, and find that none of these contribute significantly to uncertainties in {alpha}. We estimate ages and masses for the clusters by comparing their measured UBVI, H{alpha} colors with predictions from single stellar population models. The age distribution of the clusters can be approximated by a power law, dN/d{tau} {proportional_to} {tau}{sup {gamma}}, with {gamma} = -0.9 {+-} 0.2, for M {approx}> few x 10{sup 3} M {sub sun} and {tau} {approx}< 4 x 10{sup 8} yr. This indicates that clusters are disrupted quickly, with {approx}80%-90% disrupted each decade in age over this time. The mass function of clusters over the same M-{tau} range is a power law, dN/dM {proportional_to} M {sup {beta}}, with {beta} = -1.94 {+-} 0.16, and does not have bends or show curvature at either high or low masses. Therefore, we do not find evidence for a physical upper mass limit, M{sub C} , or for the earlier disruption of lower mass clusters when compared with higher mass clusters, i.e., mass-dependent disruption. We briefly discuss these implications for the formation and disruption of the clusters.
- OSTI ID:
- 21454977
- Journal Information:
- Astrophysical Journal, Vol. 719, Issue 1; Other Information: DOI: 10.1088/0004-637X/719/1/966; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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