English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The ionization feedback from HII regions modifies the properties of high-massstarless clumps (HMSCs, of several hundred to a few thousand solar masses witha size of ~0.1-1 pc), such as temperature and turbulence, on the clump scale.The question of whether the presence of HII regions modifies the core-scalefragmentation and star formation in HMSCs remains to be explored. We aim toinvestigate the difference of 0.025 pc-scale fragmentation between candidateHMSCs that are strongly impacted by HII regions and less disturbed ones. Wealso search for evidence of mass shaping and induced star formation in theimpacted HMSCs. Using the ALMA 1.3 mm continuum with a resolution of ~1.3", weimaged eight candidate HMSCs, including four impacted by HII regions andanother four situated in the quiet environment. The less-impacted HMSCs areselected on the basis of their similar mass and distance compared to theimpacted ones to avoid any possible bias linked to these parameters. A total of51 cores were detected in eight clumps, with three to nine cores for eachclump. Within our limited sample, we did not find a clear difference in the~0.025 pc-scale fragmentation between impacted and non-impacted HMSCs, eventhough HII regions seem to affect the spatial distribution of the fragmentedcores. Both types of HMSCs present a thermal fragmentation with two-levelhierarchical features at the clump thermal Jeans length ${\lambda_{J,clump}^{th}}$ and 0.3${\lambda_{J, clump}^{th}}$. The ALMA emission morphologyof the impacted HMSCs AGAL010.214-00.306 and AGAL018.931-00.029 sheds light onthe capacities of HII regions to shape gas and dust in their surroundings andpossibly to trigger star formation at ~0.025 pc-scale in HMSCs. Future ALMAsurveys covering a large number of impacted HMSCs with high turbulence areneeded to confirm the trend of fragmentation indicated in this study.

HII regions and high-mass starless clump candidates II. Fragmentation and induced star formation at ~0.025 pc scale: An ALMA continuum study