Q-IFU: A JWST/NIRSpec Integral Field Unit Survey of Luminous Quasars at z ∼ 5–6: Rest-frame Optical Nuclear Properties and Extended Nebulae

It remains debatable how billion-solar-mass supermassive black holes (SMBHs) form and evolve within the first billion years. We report results from a James Webb Space Telescope (JWST)/NIRSpec integral field unit (IFU) survey of 27 luminous quasars at z ∼ 5–6, enabling a systematic investigation of their key physical properties and the associated, extended line emission. Our sample hosts SMBHs with masses log ( M BH / M ⊙ ) ∼ 8.6 –9.7 and Eddington ratios of ∼0.1–2.6 based on H β , and the H β - and H α -based M BH are broadly consistent with each other. Our sample may have a slightly smaller median black hole (BH) mass and larger median Eddington ratio than lower-redshift quasars within the same luminosity range, although the difference could still be explained by the systematic uncertainties. They generally follow the empirical correlations between the [O iii ] λ 5007 equivalent widths and bolometric luminosities or Eddington ratios formed by lower-redshift quasars. The majority of them fall within the eigenvector 1 planes formed by lower-redshift quasars. Nevertheless, a subset of the sample shows enhanced, blueshifted [O iii ] emission associated with fast outflows. Spatially extended [O iii ] line emission is detected in six objects and shows morphologies and kinematics consistent with merging activities and/or turbulent and clumpy interstellar media (ISM). We find a possible kiloparsec-scale quasar–active galactic nucleus pair in one system, although the data could also be tentatively explained as quasar radiative feedback shaping the ISM of a merging companion galaxy. Our results provide crucial insight into the rapid growth of SMBHs and the gaseous environments they reside in at z ∼ 5–6.