Properties of the giant HII regions and bar in the nearby spiral galaxy
  NGC5430
  In order to better understand the impact of the bar on the evolution of
spiral galaxies, we measure the properties of giant HII regions and the bar in
the SB(s)b galaxy NGC5430. We use two complementary data sets, both obtained at
the Observatoire du Mont-M\'egantic: a hyperspectral data cube from the imaging
Fourier transform spectrograph SpIOMM, and high-resolution spectra across the
bar from a long-slit spectrograph. We flux-calibrate SpIOMM spectra for the
first time, and produce H{\alpha} and [NII]{\lambda}6584\r{A} intensity maps
from which we identify 51 giant HII regions in the spiral arms and bar. We
evaluate the type of activity, the oxygen abundance and the age of the young
populations contained in these giant HII regions and in the bar. Thus, we
confirm that NGC5430 does not harbour a strong AGN, and that its Wolf-Rayet
knot shows a pure HII region nature. We find no variation in abundance or age
between the bar and spiral arms, nor as a function of galactocentric radius.
These results are consistent with the hypothesis that a chemical mixing
mechanism is at work in the galaxy's disc to flatten the oxygen abundance
gradient. Using the starburst99 model, we estimate the ages of the young
populations, and again find no variations in age between the bar and the arms
or as a function of radius. Instead, we find evidence for two galaxy-wide waves
of star formation, about 7.1 Myr and 10.5 Myr ago. While the bar in NGC5430 is
an obvious candidate to trigger these two episodes, it is not clear how the bar
could induce widespread star formation on such a short time-scale.
