Feedback from massive stars at low metallicities: MUSE observations of
  N44 and N180 in the Large Magellanic Cloud
  We present MUSE integral field data of two HII region complexes in the Large
Magellanic Cloud (LMC), N44 and N180. Both regions consist of a main
superbubble and a number of smaller, more compact HII regions that formed on
the edge of the superbubble. For a total of 11 HII regions, we systematically
analyse the radiative and mechanical feedback from the massive O-type stars on
the surrounding gas. We exploit the integral field property of the data and the
coverage of the HeII$\lambda$5412 line to identify and classify the
feedback-driving massive stars, and from the estimated spectral types and
luminosity classes we determine the stellar radiative output in terms of the
ionising photon flux $Q_{0}$. We characterise the HII regions in terms of their
sizes, morphologies, ionisation structure, luminosity and kinematics, and
derive oxygen abundances via emission line ratios. We analyse the role of
different stellar feedback mechanisms for each region by measuring the direct
radiation pressure, the pressure of the ionised gas, and the pressure of the
shock-heated winds. We find that stellar winds and ionised gas are the main
drivers of HII region expansion in our sample, while the direct radiation
pressure is up to three orders of magnitude lower than the other terms. We
relate the total pressure to the star formation rate per unit area,
$\Sigma_{SFR}$, for each region and find that stellar feedback has a negative
effect on star formation, and sets an upper limit to $\Sigma_{SFR}$ as a
function of increasing pressure.
