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 radio-loud/radio-quiet (RL/RQ) dichotomy in quasars is still an openquestion. Although it is thought that accretion onto supermassive black holesin the centre the host galaxies of quasars is responsible for some radiocontinuum emission, there is still a debate as to whether star formation oractive galactic nuclei (AGN) activity dominate the radio continuum luminosity.To date, radio emission in quasars has been investigated almost exclusivelyusing high-frequency observations in which the Doppler boosting might have animportant effect on the measured radio luminosity, whereas extended structures,best observed at low radio frequencies, are not affected by the Dopplerenhancement. We used a sample of quasars selected by their optical spectra inconjunction with sensitive and high-resolution low-frequency radio dataprovided by the LOw Frequency ARray (LOFAR) as part of the LOFAR Two-Metre SkySurvey (LoTSS) to investigate their radio properties using the radio loudnessparameter ($\mathcal{R} = \frac{L_{\mathrm{144-MHz}}}{L_{\mathrm{i\,band}}}$).The examination of the radio continuum emission and RL/RQ dichotomy in quasarsexhibits that quasars show a wide continuum of radio properties (i.e. no clearbimodality in the distribution of $\mathcal{R}$). Radio continuum emission atlow frequencies in low-luminosity quasars is consistent with being dominated bystar formation. We see a significant albeit weak dependency of $\mathcal{R}$ onthe source nuclear parameters. For the first time, we are able to resolve radiomorphologies of a considerable number of quasars. All these crucial resultshighlight the impact of the deep and high-resolution low-frequency radiosurveys that foreshadow the compelling science cases for the Square KilometreArray (SKA).

LoTSS/HETDEX: Optical quasars I. Low-frequency radio properties of optically selected quasars