Star Formation Histories of the LEGUS Spiral Galaxies. I. The flocculent
  spiral NGC 7793
  We present a detailed study of the flocculent spiral galaxy NGC 7793, part of
the Sculptor group. By analyzing the resolved stellar populations of the
galaxy, located at a distance of ~3.7 Mpc, we infer for the first time its
radial star formation history (SFH) from Hubble Space Telescope photometry,
thanks to both archival and new data from the Legacy ExtraGalactic UV Survey.
We determine an average star formation rate (SFR) for the galaxy portion
covered by our F555W and F814W data of 0.23 +- 0.02 Msun/yr over the whole
Hubble time, corresponding to a total stellar mass of 3.09 +- 0.33 x 10^9 Msun
in agreement with previous determinations. Thanks to the new data extending to
the F336W band, we are able to analyze the youngest stellar populations with a
higher time resolution. Most importantly, we recover the resolved SFH in
different radial regions of the galaxy; this shows an indication of a growing
trend of the present-to-past SFR ratio, increasing from internal to more
external regions, supporting previous findings of the inside-out growth of the
galaxy.
