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Paper: Age Dating a Starburst: Gemini/CIRPASS Observations of the Core of M 83
Volume: 320, The Neutral ISM in Starburst Galaxies
Page: 311
Authors: Ryder, S.; Knapen, J.; Mazzuca, L.; Sharp, R.; Parry, I.
Abstract: The circumnuclear starburst in NGC 5236 (M 83) has been studied photometrically by Harris et al. (2001) using HST/WFPC2 images in the broad-band near-UV and optical, as well as narrow-band Hα and Hβ to derive colors and line equivalent widths for 45 clusters. Despite the excellent spatial resolution of these observations, optical photometric analyses such as this suffer from: (i) patchy (and not easily quantifiable) dust extinction; (ii) the fact that the reddening vector parallels the evolutionary tracks in a two-color diagram; and (iii) selection effects, which tend to exclude the very youngest (t < 5 Myr) clusters which have strong emission lines, but only a weak stellar continuum. Additionally, it is not possible to distinguish an instantaneous burst of star formation from a constant star formation rate, on the basis of broad-band colors alone.

To help overcome these drawbacks, we have used the Cambridge Infra-Red Panoramic Survey Spectrograph (CIRPASS; Parry et al. 2000) in Integral Field Unit (IFU) mode on the 8.1m Gemini South Telescope to map the equivalent widths of the Paβ line and the CO(6,3) band across much of the circumnuclear star-forming region in M83. As demonstrated by Ryder, Knapen, & Takamiya (2001) for M100, the combination of two such diagnostics constrains not just the age, but also the burst duration, for any cluster within the IFU field of view, allowing us to compile an unbiased account of the recent star formation history.
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