Nebular emission lines towards NGC3372 center

The main result is that the bulk of the emission lines in the central part of Carina arise from several distinct shell-like expanding regions, the most evident found around {eta} Car, the Trumpler 14 core, and the star WR25. These "shells" are non-spherical and show distortions probably caused by collisions with other shells or colder, higher-density gas. Some of them are also partially obscured by foreground dust lanes, while very little dust is found in their interior.

Preferential directions, parallel to the dark dust lanes, are found in the shell geometries and physical properties, probably related to strong density gradients in the studied region. We also find evidence that the ionizing flux emerging from {eta} Car and the surrounding Homunculus nebula varies with polar angle. The high-velocity components in the wings of H{alpha} are found to arise from expanding dust reflecting the {eta} Car spectrum.