A $z\sim$ 6.2 Quasar on the Local M${}_{\mathrm{BH}}$-${\sigma }_{\ast }$ Relation Quenching Its Host Galaxy from the Aether Survey

Abstract

We report JWST/NIRSpec integral field unit (IFU) observations of the quasar J1512$+$4422 at $z\sim 6.2$ from the Aether survey. At $\sim$900 Myr after the Big Bang, this object already lies on the $M_{\mathrm{BH}}$-${\sigma }_{\ast }$ relation found in the local universe, with an $M_{\mathrm{BH}}\simeq 8.9\times 10^8{M}_{\odot }$ and a stellar velocity dispersion ${\sigma }_{\ast }\simeq 288$ km s${}^{-1}$. We detect an outflow with a velocity of $\sim$478 km s${}^{-1}$ in the nuclear region, which likely extends to $\sim$3.2 kpc in projection and has a median velocity of $\sim$352 km s${}^{-1}$. The outflow dynamical time scale ($\sim$ 9 Myr) is consistent with the time scale of the current quenching process based on the star formation history as reported previously. The total mass outflow rate (92.6${}_{-74.1}^{+92.6}$ M${}_{\odot }$ yr${}^{-1}$) is larger than the current star formation rate (0.9${}_{-0.8}^{+3.8}$ or 4.3${}_{-3.7}^{+5.8}$ M${}_{\odot }$ yr${}^{-1}$), and the total kinetic energy outflow rate (0.6${}_{-0.5}^{+0.6}$\% of quasar luminosity) meets the threshold for negative quasar feedback as suggested by simulations. These results suggest that the outflow is capable of suppressing/quenching the star formation activity within the host galaxy. Furthermore, J1512$+$4422 exhibits ${\sigma }_{\ast }$, stellar mass and size similar to those of $z\gtrsim$ 3 quiescent/post-starburst galaxies, implying a link between the two. Overall, for objects like J1512$+$4422, the evolution of their SMBHs and host galaxies appears to be tightly coupled within the first billion years. The quasar feedback likely plays a critical role in both placing them on the $M_{\mathrm{BH}}$--${\sigma }_{\ast }$ relation and quenching.

19 pages, 8 figures, 2 tables, submitted to ApJ. Comments are more than welcome!