Energetic feedback and $^{26}$Al from massive stars and their supernovae
  in the Carina region
  We study the populations of massive stars in the Carina region and their
energetic feedback and ejection of $^{26}$Al. We did a census of the stellar
populations in young stellar clusters within a few degrees of the Carina
Nebula. For each star we estimated the mass, based on the spectral type and the
host cluster age. We used population synthesis to calculate the energetic
feedback and ejection of $^{26}$Al from the winds of the massive stars and
their supernova explosions. We used 7 years of INTEGRAL observations to measure
the $^{26}$Al signal from the region. The INTEGRAL $^{26}$Al signal is not
significant with a best-fit value of about 1.5e-5 ph/cm^2/s, approximately half
of the published Compton Gamma Ray Observatory (CGRO) result, but in agreement
with the latest CGRO estimates. Our analysis of the stellar populations in the
young clusters leads to an expected signal of half the observed value, but the
results are consistent within 2 sigma. We find that the fraction of $^{26}$Al
ejected in Wolf-Rayet winds is high, and the observed signal is unlikely to be
caused by $^{26}$Al ejected in supernovae alone, indicating a strong wind
ejection of $^{26}$Al. Due to the lack of prominent O stars, regions with ages
$\gtrsim$10 Myr are often neglected in studies of OB associations. We find that
in the Carina region such clusters contribute significantly to the stellar mass
and the energetics of the region.
