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

We present a SCUBA submillimetre (450 & 850 micron) survey of the environmentof 105 IRAS point sources, selected from the Wood & Churchwell (1989a) andKurtz, Churchwell & Wood (1994) radio ultracompact (UC) HII region surveys. Wedetected a total of 155 sub-mm clumps associated with the IRAS point sourcesand identified three distinct types of object: ultracompact cm-wave sourcesthat are not associated with any sub-mm emission (sub-mm quiet objects), sub-mmclumps that are associated with ultracompact cm-wave sources (radio-loudclumps); and sub-mm clumps that are not associated with any known ultracompactcm-wave sources (radio-quiet clumps). 90% of the sample of IRAS point sourceswere found to be associated with strong sub-mm emission. We consider the sub-mmcolours, morphologies and distance-scaled fluxes of the sample of sub-mm clumpsand show that the sub-mm quiet objects are unlikely to represent embedded UCHII regions unless they are located at large heliocentric distances. Many ofthe 2.5 arcmin SCUBA fields contain more than one sub-mm clump, with an averagenumber of companions (the companion clump fraction) of 0.90. The clumps aremore strongly clustered than other candidate HMPOs and the mean clump surfacedensity exhibits a broken power-law distribution with a break at 3 pc. Wedemonstrate that the sub-mm and cm-wave fluxes of the majority of radio-loudclumps are in excellent agreement with the standard model of ultracompact HIIregions. We speculate on the nature of the radio-quiet sub-mm clumps and,whilst we do not yet have sufficient data to conclude that they are in a pre-UCHII region phase, we argue that their characteristics are suggestive of such astage.

A SCUBA imaging survey of ultracompact HII regions