2020/02/29 by L. Zappacosta, E. Piconcelli, M. Giustini +14 · 1 citation
Physics and Astronomy · #astro-ph.GA #astro-ph.HE
paper · pdf · doi:10.1051/0004-6361/201937292
published as A&A 635, L5 (2020) · 10 pages (including Appendix), 4 figures. Astronomy & Astrophysics Letters in press. Title numbering changed to match the published version
arxiv created 2020/03/17 · arxiv updated 2020/03/18
Hyperluminous quasars (L\rm bol\gtrsim 1047 erg s-1) are ideal laboratories to study the interaction and impact of extreme radiative field and the most powerful winds in the AGN nuclear regions. They typically exhibit low coronal X-ray luminosity (L\rm X) compared to the UV and MIR radiative outputs (L\rm UV and L\rm MIR) with a non-negligible fraction of them reporting even ∼1 dex weaker L\rm X compared to the prediction of the well established L\rm X-L\rm UV and L\rm X-L\rm MIR relations followed by the bulk of the AGN population. We report in our WISE/SDSS-selected Hyperluminous (WISSH) z=2-4 broad-line quasar sample, the discovery of a dependence between the intrinsic 2-10 keV luminosity (L\rm 2-10) and the blueshifted velocity of the CIV emission line (v\rm CIV) indicative of accretion disc winds. In particular, sources with fastest winds (v\rm CIV\gtrsim 3000~\rm km s-1) possess ∼0.5-1 dex lower L\rm 2-10 than sources with negligible v\rm CIV. No similar dependence is found on L\rm UV, L\rm MIR, L\rm bol, photon index and absorption column density. We interpret these findings in the context of accretion disc wind models. Both magnetohydrodynamic and line-driven models can qualitatively explain the reported relations as a consequence of X-ray shielding from the inner wind regions. In case of line-driven winds, the launch of fast winds is favoured by a reduced X-ray emission, and we speculate that these winds may play a role in directly limiting the coronal hard X-ray production.