Evidence for active galactic nucleus driven outflows in young radio quasars

We present near-infrared spectra of young radio quasars (P 1.4 GHz ≈ 26-27 W Hz–1) selected from the Wide-Field Infrared Survey Explorer. The detected objects have typical redshifts of z ≈ 1.6-2.5 and bolometric luminosities ~1047 erg s–1. Based on the intensity ratios of narrow emission lines, we find that these objects are mainly powered by active galactic nuclei (AGNs), although star formation contribution cannot be completely ruled out. The host galaxies experience moderate levels of extinction, AV ≈ 0-1.3 mag. The observed [O III] λ5007 luminosities and rest-frame J-band magnitudes constrain the black hole masses to lie in the range ~108.9-109.7 M ☉. From the empirical correlation between black hole mass and host galaxy mass, we infer stellar masses of ~1011.3-1012.2 M ☉. The [O III] line is exceptionally broad, with FWHM ~1300-2100 km s–1, significantly larger than that of ordinary distant quasars. We argue that these large line widths can be explained by jet-induced outflows, as predicted by theoretical models of AGN feedback.