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 an estimate of the optical luminosity function (OLF) of LOFARradio-selected quasars (RSQs) at $1.4<z<5.0$ in the $9.3\:\textrm{deg}^{2}$NOAO Deep Wide-field survey (NDWFS) of the Bo\"otes field. The selection wasbased on optical/mid-ir photometry used to train three different machinelearning (ML) algorithms. Objects taken as quasars by the ML algorithms arerequired to be detected at $5\sigma$ significance in deep radio maps to beclassified as candidate quasars. The optical imaging came from the SDSS and thePS1 $3\pi$ survey; mid-ir photometry was taken from the SDWFS survey; and radiodata was obtained from deep LOFAR imaging of the NDWFS-Bo\"otes field. Therequirement of a $5\sigma$ LOFAR detection allowed us to reduce the stellarcontamination in our sample by two orders of magnitude. The sample comprises134 objects, including both photometrically selected candidate quasars (47) andspectroscopically confirmed quasars (83). The depth of our LOFAR observationsallowed us to detect the radio-emission of quasars that would be otherwiseclassified as radio-quiet. Around $65\%$ of the quasars in the sample arefainter than $M_{\textrm{1450}}=-24.0$, a regime where the OLF of quasarsselected through their radio emission, has not been investigated in detail. Ithas been demonstrated that in cases where mid-ir wedge-based AGN selection isnot possible due to a lack of appropriate data, the selection of quasars usingML algorithms trained with optical/mid-ir photometry in combination with LOFARdata provides an excellent approach for obtaining samples of quasars. Wedemonstrate that RSQs show an evolution similar to that exhibited by faintquasars $(M_{\textrm{1450}}\leq-22.0)$. Finally, we find that RSQs may composeup to $\sim20\%$ of the whole faint quasar population (radio-detected plusradio-undetected).

The optical luminosity function of LOFAR radio-selected quasars at $1.4\leq z\leq5.0$ in the NDWFS-Bo\"otes field