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		| Paper: | 
		Resolved Stars in M83 Based on HST/WFC3 Early Release  Science Observations | 
	 
	
		| Volume: | 
		440, UP2010: Have Observations Revealed a Variable Upper End of the Initial Mass Function? | 
	 
	
		| Page: | 
		149 | 
	 
	
		| Authors: | 
		Kim, H.; Whitmore, B. C.; Windhorst, R. A. | 
	 
	
	
		| Abstract: | 
		We present a multi-wavelength photometric study of individual stars in
 M83 based on observations taken as part of the WFC3 Early Release
 Science (ERS) program.  The central region of M83 has been imaged in
 seven broad-band filters to obtain multi-wavelength coverage from the
 near-UV to the near-IR.  We use four filters–F336W, F438W, F555W, and
 F814W–to measure the UBVI photometric colors and intrinsic
 luminosity for ∼10,000 stars.  These measurements are used to
 determine the recent (< 1 Gyr) star formation history of M83.  We
 selected 50 regions in the spiral arm and the inter-arm area of M83
 and categorize them based on their Hα morphology.  To determine
 ages of stars in each region, the color-magnitude diagrams (CMDs) and
 the color-color diagrams were used with the Padova isochrones at a
 metallicity of Z=0.03 (1.5 Z☉).  We correct the foreground and
 internal extinction of individual stars using the reddening-free Q
 parameter and improve our age estimates of stars from the isochrone
 fitting on the CMDs.  Comparisons of stellar ages and cluster ages
 based on both their Hα morphology and their spectral energy
 distribution (SED) fitting were made and show fairly good
 correlations.  We also find that the regions with ages determined
 younger than 10 Myr are located preferentially along the active
 star-forming regions on the spiral arm. | 
	 
	
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