A Recent Starbust in the Low Surface Brightness Galaxy UGC 628
  We present the star-formation history of the low surface brightness (LSB)
galaxy UGC 628 as part of the MUSCEL program (MUltiwavelength observations of
the Structure, Chemistry, and Evolution of LSB galaxies). The star-formation
histories of LSB galaxies represent a significant gap in our knowledge of
galaxy assembly, with implications for dark matter / baryon feedback, IGM gas
accretion, and the physics of star formation in low metallicity environments.
Our program uses ground-based IFU spectra in tandem with space-based UV and IR
imaging to determine the star-formation histories of LSB galaxies in a
spatially resolved fashion. In this work we present the fitted history of our
first target to demonstrate our techniques and methodology. Our technique
splits the history of this galaxy into 15 semi-logarithmically spaced
timesteps. Within each timestep the star-formation rate of each spaxel is
assumed constant. We then determine the set of 15 star-formation rates that
best recreate the spectra and photometry measured in each spaxel. Our main
findings with respect to UGC 628 are: a) the visible properties of UGC 628 have
varied over time, appearing as a high surface brightness spiral earlier than 8
Gyr ago and a starburst galaxy during a recent episode of star formation
several tens of Myr ago, b) the central bar/core region was established early,
around 8-10 Gyr ago, but has been largely inactive since, and c) star formation
in the past 3 Gyr is best characterised as patchy and sporadic.
