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 aim of this study is to investigate the distribution and excitation ofthe methanol gas around Cep A and to describe the physical conditions of theregion. In addition the large scale abundance distribution is determined inorder to understand the morphology and kinematics of star forming regions inwhich methanol masers occur. The spatial distribution of the methanol isstudied by mapping line emission, as well as the column density and excitationtemperature, which are estimated using rotation diagrams. For a limited numberof positions the parameters are checked with non-LTE models. Furthermore, thedistribution of the methanol abundance is derived in comparison with archivaldust continuum maps. Methanol is detected over a 0.3x0.15 pc area centred onthe Cep A HW2 source, showing an outflow signature. Most of the gas can becharacterized by a moderately warm rotation temperature (30-60K). At thecentral position two velocity components are detected with different excitationcharacteristics, the first related to the large-scale outflow. The secondcomponent, uniquely detected at the central location, is probably associatedwith the maser emission on much smaller scales of 2". Detailed analysis revealsthat the highest densities and temperatures occur for these inner components.In the inner region the dust and gas are shown to have different physicalparameters. Abundances of methanol in the range 10E-9 - 10E-7 are inferred,with the abundance peaking at the maser position. The geometry of thelarge-scale methanol is in accordance with previous determinations of the Cep Ageometry, in particular those from methanol masers. The dynamical and chemicaltime-scales are consistent with the methanol originating from a single drivingsource associated with the HW2 object and the masers in its equatorial region.

Distribution and excitation of thermal methanol in 6.7 GHz maser bearing star-forming regions; I. The nearby source Cepheus A