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 the observational results from the 43-GHz Very Long Baseline Array(VLBA) observations of 124 compact radio-loud active galactic nuclei (AGNs)that were conducted between 2014 November and 2016 May. The typical dimensionsof the restoring beam in each image are about 0.5 mas $\times$ 0.2 mas. Thehighest resolution of 0.2 mas corresponds to a physical size of 0.02 pc for thelowest redshift source in the sample. The 43-GHz very long baselineinterferometry (VLBI) images of 97 AGNs are presented for the first time. Westudy the source compactness on milli-arcsec (mas) and sub-mas scales, andsuggest that 95 sources in our sample are suitable for future space VLBIobservations. By analyzing our data supplemented with other VLBA AGN surveysfrom literature, we find that the core brightness temperature increases withincreasing frequency below a break frequency ~ 7 GHz, and decreases between~7--240~GHz but increases again above~240 GHz in the rest frame of the sources.This indicates that the synchrotron opacity changes from optically thick tothin. We also find a strong statistical correlation between radio and$\gamma$-ray flux densities. Our correlation is tighter than those inliterature derived from lower-frequency VLBI data, suggesting that the$\gamma$-ray emission is produced more co-spatially with the 43-GHz VLBA coreemission. This correlation can also be extrapolated to the un-beamed AGNpopulation, implying that a universal $\gamma$-ray production mechanism mightbe at work for all types of AGNs.

Compact Bright Radio-loud AGNs -- III. A Large VLBA Survey at 43 GHz