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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Context. Gas ionized by starburst activity radiates radio recombination lines(RRLs), from which one can derive the plasma conditions and the number ofmassive stars formed in the burst, free of dust obscuration effects.  Aims. We aimed to find RRL emission from additional starburst systems and touse the line properties to estimate the properties of the ionized gas.  Methods. We conducted a search for RRLs in the nearby extragalactic starburstor Seyfert galaxies NGC 1808, the Circinus galaxy, NGC 4038/9, II Zw 40, NGC6221, NGC 7552, IRAS 18325-5926, IC 5063, and VV 114. We used the VLA and theATCA to search for the RRLs H91alpha and H92alpha with rest frequencies of 8.6GHz and 8.3 GHz.  Results. We detected for the first time RRLs from the starburst nuclei in theCircinus galaxy and NGC 1808. The Circinus galaxy was detected with a linestrength integrated over the source of 3.2 mJy, making it the fourth-strongestextragalactic RRL emitter known at this frequency (after NGC 4945, M 82, andNGC 253). The line and continuum emission can be matched by a model consistingof a collection of 50 to 10 000 H II regions with 300 to 9000 O5 stars requiredto maintain the ionization, inferring a star formation rate of 0.2 Msun/yr to 6Msun/yr. NGC 1808 was detected in RRL emission at 3.9 sigma with a linestrength of 0.47 mJy at the expected velocity.  Conclusion. We have detected RRLs from two galaxies, adding to the small butgrowing number of known extragalactic RRL emitters. The Circinus galaxy isstrong and especially suited to high-quality follow-up spectroscopic study. Wederived conditions and star formation rates in the starbursting regions.Uncertainties can be reduced by future multi-transition studies.

Detection of the H92alpha recombination line from the starbursts in the Circinus galaxy and NGC 1808