The Distribution of Dense Cores near HII Regions. (arXiv:1908.05622v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bobotsis_G/0/1/0/all/0/1">George Bobotsis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fich_M/0/1/0/all/0/1">Michel Fich</a>
An investigation of dust emission associated with a large sample of HII
regions has been carried out. Stacked results from this sample suggest that
each HII region is at or near the center of a cluster of dense cores, that
extends far beyond the HII region, and has volume density that decreases as
r^(-3). The data also shows evidence for enhanced numbers of cores near the
boundary of the HII regions. At the same time, a significant decrease in the
number of cores, consistent with no cores, is observed in the interior of these
HII regions. Neither these HII regions, nor their associated massive OB stars
were found to have a significant heating effect on their associated dusty
clumps. Clouds, or the outermost layers of the clumps in which the cores are
embedded, are found to exert a strong shielding effect to external heating
sources. Despite this, a large portion of the identified cores was found to be
warmer than their surrounding cloud and consequently may be in the initial
stages of star formation. The star formation efficiency of the 7 HII region
systems with the most reliable mass budgets ranged between 1% and 9%.
An investigation of dust emission associated with a large sample of HII
regions has been carried out. Stacked results from this sample suggest that
each HII region is at or near the center of a cluster of dense cores, that
extends far beyond the HII region, and has volume density that decreases as
r^(-3). The data also shows evidence for enhanced numbers of cores near the
boundary of the HII regions. At the same time, a significant decrease in the
number of cores, consistent with no cores, is observed in the interior of these
HII regions. Neither these HII regions, nor their associated massive OB stars
were found to have a significant heating effect on their associated dusty
clumps. Clouds, or the outermost layers of the clumps in which the cores are
embedded, are found to exert a strong shielding effect to external heating
sources. Despite this, a large portion of the identified cores was found to be
warmer than their surrounding cloud and consequently may be in the initial
stages of star formation. The star formation efficiency of the 7 HII region
systems with the most reliable mass budgets ranged between 1% and 9%.
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