Walch, Stefanie, Whitworth, Anthony Peter ![]() |
Abstract
Perfect bubbles like that surrounding the galactic HII region RCW 120 (Deharveng et al. 2009) have been interpreted as proof of concept for the collect and collapse (C & C) mechanism of triggered star formation. The cold, dusty clumps surrounding RCW 120 are aligned along an almost spherical shell. It has been inferred that these massive clumps, which sometimes harbour young stellar objects, have been formed via the fragmentation of the dense, swept-up shell. In order to better understand the triggering mechanisms at work in shells like RCW 120, we perform high-resolution, three dimensional SPH simulations of HII regions expanding into fractal molecular clouds. In a second step, we use RADMC-3D to compute the synthetic dust continuum emission from our simulations, in order to compare them with observations of RCW 120 made with APEX-LABOCA at 870 micron. We show that a distribution of clumps similar to the one seen in RCW 120 can readily be explained by a non-uniform underlying molecular cloud structure. Hence, a shell-like clump configuration around an HII region does not necessarily support the C & C scenario, but rather reflects the pre-existing, non-uniform density distribution of the molecular cloud into which the HII region expands.
Item Type: | Article |
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Date Type: | Submission |
Status: | Submitted |
Schools: | Physics and Astronomy |
Subjects: | Q Science > QB Astronomy |
Publisher: | IOP Science |
ISSN: | 0004-637X |
Last Modified: | 20 Oct 2022 10:03 |
URI: | https://orca.cardiff.ac.uk/id/eprint/33950 |
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