NARDINI, EMANUELEEMANUELENARDINIElisabeta LussoBisogni, SusannaSusannaBisogni2021-02-252021-02-2520191745-3925http://hdl.handle.net/20.500.12386/30626We report on the detection of a blueshifted Fe K absorption feature in two consecutive XMM-Newton observations of the luminous blue quasar Ton 28, at the 4$\sigma$ cumulative significance. The rest energy of 9.2 keV implies the presence of an accretion disc wind with bulk outflow velocity of $\sim$0.28$c$, while the kinetic power is most likely a few per cent of the quasar luminosity. Remarkably, Ton 28 had been specifically selected as an optimal target to reveal an ultra-fast X-ray wind based on its total luminosity ($L_{\rm bol} > 10^{46}$ erg s$^{-1}$) and [OIII] $\lambda$5007\AA\ equivalent width (EW < 6 \AA), suggestive of high accretion rate and low inclination, respectively. Other peculiar optical/UV emission-line properties include narrow H$\beta$, strong FeII and blueshifted CIV. These are key parameters in the Eigenvector 1 formalism, and are frequently found in active galaxies with ongoing accretion disc winds, hinting at a common physical explanation. Provided that the effectiveness of our selection method is confirmed with similar sources, this result could represent the first step towards the characterization of black-hole winds through multiwavelength indicators in the absence of high-quality X-ray spectra.STAMPAenArticle10.1093/mnrasl/sly2042-s2.0-85084312170000482176700028http://arxiv.org/abs/1811.00012v1https://academic.oup.com/mnrasl/article/482/1/L134/51495012019MNRAS.482L.134NFIS/05 - ASTRONOMIA E ASTROFISICA