The 100 Myr Star Formation History of NGC 5471 from Cluster and Resolved
  Stellar Photometry
  We show that star formation in the giant HII region NGC 5471 has been ongoing
during the past 100 Myr. Using HST/WFPC2 F547M and F675W, ground based JHKs,
and GALEX FUV and NUV images, we have conducted a photometric study of the star
formation history in the massive giant extragalactic HII region NGC 5471 in
M101. We perform a photometric study of the colour-magnitude diagram (CMD) of
the resolved stars, and an integrated analysis of the main individual star
forming clusters and of NGC 5471 as a whole. The integrated UV-optical-nIR
photometry for the whole region provides two different reference ages, 8 Myr
and 60 Myr, revealing a complex star formation history, clearly confirmed by
the CMD resolved stellar photometry analysis. The spatial distribution of the
stars shows that the star formation in NGC 5471 has proceeded along the whole
region during, at least, the last 100 Myr. The current ionizing clusters are
enclosed within a large bubble, which is likely to have been produced by the
stars that formed in a major event < 20 Myr ago.
