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 for clusters outside of the very crowded starburst nucleus can be approximated by a power law , dN / dL \propto L ^ { \alpha } , with \alpha = -2.04 \pm 0.08 , down to M _ { V } \approx - 5.5 .
We test the sensitivity of the luminosity function 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 \propto \tau ^ { \gamma } , with \gamma = -0.9 \pm 0.2 , for M \mathrel { > \kern - 10.0 pt \lower 3.87 pt \hbox { $ \sim$ } } \mbox { few } \times 10 ^ { 3 } ~ { } M _ % { \odot } and \tau \mathrel { < \kern - 10.0 pt \lower 3.87 pt \hbox { $ \sim$ } } 4 \times 10 ^ { 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 \propto M ^ { \beta } , with \beta = -1.94 \pm 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 _ { 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 .