Volume 531, July 2011
|Number of page(s)||13|
|Published online||01 June 2011|
C+ emission from the Magellanic Clouds
II. [C II] maps of star-forming regions LMC-N 11, SMC-N 66, and several others
Sterrewacht Leiden, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
2 Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80303, USA
Received: 15 December 2010
Accepted: 18 March 2011
Context. We study the λ 158 μm [C II] fine-structure line emission from star-forming regions as a function of metallicity.
Aims. We have measured and mapped the [C II] emission from the very bright HII region complexes N 11 in the LMC and N 66 in the SMC; as well as the SMC H II regions N 25, N 27, N 83/N 84, and N 88 with the FIFI instrument on the Kuiper Airborne Observatory.
Methods. In both LMC and SMC, the ratio of [C II] line to CO line and to the far-infrared continuum emission is much higher than seen almost anywhere else, including Milky Way star-forming regions, and whole galaxies.
Results. In the low metallicity, low dust-abundance environment of the LMC and the SMC UV mean free path lengths are much greater than those in the higher-metallicity Milky Way. The increased photoelectric heating efficiencies cause significantly greater relative [C II] line emission strengths. At the same time, similar decreases in PAH abundances have the opposite effect by diminishing photoelectric heating rates. Consequently, in low-metallicity environments relative [C II] strengths are high but exhibit little further dependence on actual metallicity. Relative [C II] strengths are slightly higher in the LMC than in the SMC which has both lower dust and lower PAH abundances.
Key words: ISM: clouds / galaxies: ISM / Magellanic Clouds / infrared: ISM / dust, extinction
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.