2012A&A...541A.132P

The Carina Nebula represents one of the most massive star forming regions known in our Galaxy and displays a high level of feedback from the large number of very massive stars. While the stellar content is now well known from recent deep X-ray and near-infrared surveys, the properties of the clouds remained rather poorly studied until today. By mapping the Carina Nebula complex in the far-infrared, we aim at a comprehensive and detailed characterization of the dust and gas clouds in the complex. We used SPIRE and PACS onboard of Herschel to map the full spatial extent (≃5.3 square-degrees) of the clouds in the Carina Nebula complex at wavelengths between 70µm and 500µm. We used here the 70 µm and 160 µm far-infrared maps to determine color temperatures and column densities, and to investigate the global properties of the gas and dust clouds in the complex. Our Herschel maps show the far-infrared morphology of the clouds at unprecedented high angular resolution. The clouds show a very complex and filamentary structure that is dominated by the radiation and wind feedback from the massive stars. In most locations, the column density of the clouds is N_H≲2x10²²cm^–2 (corresponding to visual extinctions of A_V≲10mag); denser cloud structures are restricted to the massive cloud west of Tr 14 and the innermost parts of large pillars. Our temperature map shows a clear large-scale gradient from ≃35-40K in the central region to ≲20K at the periphery and in the densest parts of individual pillars. The total mass of the clouds seen by Herschel in the central (1 degree radius) region is ≃656000M_☉. We also derive the global spectral energy distribution in the mid-infrared to mm wavelength range. A simple radiative transfer model suggests that the total mass of all the gas (including a warmer component that is not well traced by Herschel) in the central 1 degree radius region is ≤890000M_☉. Despite the strong feedback from numerous massive stars and the corresponding cloud dispersal processes that are going on since several million years, there are still several 10000M_☉ of cool cloud material present at column-densities sufficient for further star formation. Comparison of our total gas mass estimates to molecular cloud masses derived from CO line mapping suggests that as much as about 75% of all the gas is in atomic rather than molecular form.