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

Atomic hydrogen masers occur in recombination plasmas in sufficiently denseHII regions. These hydrogen recombination line (HRL) masers have been observedin a handful of objects to date and the analysis of the atomic physics involvedhas been rudimentary. In this work a new model of HRL masers is presented whichuses an nl-model to describe the atomic populations interacting with free-freeradiation from the plasma, and an escape probability framework to deal withradiative transfer effects. The importance of including the collisions betweenangular momentum quantum states and the free-free emission in models of HRLmasers is demonstrated. The model is used to describe the general behaviour ofradiative transfer of HRLs and to investigate the conditions under which HRLmasers form. The model results show good agreement with observations collectedover a broad range of frequencies. Theoretical predictions are made regardingthe ratio of recombination lines from the same upper quantum level for theseobjects.

An nl-model with radiative transfer for hydrogen recombination line masers