  We quantified the effects of stellar feedback in RCW 49 by determining the
physical conditions in different regions using the [CII] 158 $\mu$m and [OI] 63
$\mu$m observations from SOFIA, the $^{12}$CO (3-2) observations from APEX and
the H$_2$ line observations from Spitzer telescopes. Large maps of RCW 49 were
observed with the SOFIA and APEX telescopes, while the Spitzer observations
were only available towards three small areas. From our qualitative analysis,
we found that the H$_2$ 0-0 S(2) emission line probes denser gas compared to
the H$_2$ 0-0 S(1) line. In four regions ("northern cloud", "pillar", "ridge",
and "shell"), we compared our observations with the updated PDR Toolbox models
and derived the integrated far-ultraviolet flux between 6-13.6 eV ($G_{\rm
0}$), H nucleus density ($n$), temperatures and pressures. We found the ridge
to have the highest $G_{\rm 0}$ (2.4 $\times$ 10$^3$ Habing units), while the
northern cloud has the lowest $G_{\rm 0}$ (5 $\times$ 10$^2$ Habing units).
This is a direct consequence of the location of these regions with respect to
the Wd2 cluster. The ridge also has a high density (6.4 $\times$ 10$^3$
cm$^{-3}$), which is consistent with its ongoing star formation. Among the
Spitzer positions, we found the one closest to the Wd2 cluster to be the
densest, suggesting an early phase of star formation. Furthermore, the Spitzer
position that overlaps with the shell was found to have the highest $G_{\rm 0}$
and we expect this to be a result of its proximity to an O9V star.

Astrophysics of Galaxies