Speaker
Description
Quasars have historically been classified into two distinct classes, radio-loud (RL) and radio-quiet (RQ), taking into account the presence and absence of relativistic radio jets, respectively. Although different attempts were made to unify these two classes, there is a long-standing open debate involving the possibility of a real physical dichotomy between RL and RQ quasars. To address this, we present new high S/N spectra of 11 extremely powerful quasars with radio to optical flux density ratio > 1000 that concomitantly cover the Mgii𝜆2800 and H𝛽 in the redshift range 0.35 < z < 1, observed at Calar Alto Observatory (Spain). We aim to quantify broad emission line differences between RL and RQ quasars by using the four dimensional eigenvector 1 (4DE1) parameter space and its Main Sequence (MS), and to check the effect of powerful radio ejection on the low ionization broad emission lines. Emission lines are analysed by doing two complementary approaches, a multicomponent non-linear fitting, and analysing the lines through parameters such as centroid shifts at different intensities, asymmetry and kurtosis indices. We found that broad emission lines show large redward asymmetry both in H𝛽 and Mgii2800A. The location of our RL sources in a UV plane looks similar to the optical one, with weak Feii emission and broad Mgii2800A. We supplement the 11 sources with large samples from previous work. Compared to RQ, our extreme RL quasars show larger median H𝛽 FWHM Feii emission, larger 𝑀BH, lower 𝐿bol/𝐿Edd, and a restricted space occupation in the optical and UV planes. The differences are more elusive when the comparison is carried out by restricting the RQ population to the region of the MS occupied by RL quasars, albeit an unbiased comparison matching 𝑀BH and 𝐿bol/𝐿Edd suggests that the most powerful RL quasars show the highest redward asymmetries in H𝛽.
| Stream | Science or Engineering |
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