A quasar-galaxy merger at z~6.2: Black hole mass and quasar properties from the NIRSpec spectrum

Vol. 685
4. Extragalactic astronomy

A quasar-galaxy merger at z~6.2: Black hole mass and quasar properties from the NIRSpec spectrum

The authors used JWST NIRSpec to obtain high resolution integral field spectroscopy of the spectacular system composed of a quasar host interacting with two companion galaxies, namely PJ308-21 at z=6.23. The quasar has an inferred black hole mass of 2-3x10^9 Msol and an Eddington ratio of 0.67, which is in line with the population of the most distant quasars. Most notably, the new data reveal the presence of significant outflowing ionized gas, which was detected thanks to an accurate modeling of the [OIII] emission which is blue-shifted by almost 2000 km/s. Such high velocity outflows in early galaxies are predicted by models to play a significant role in regulating black hole and galaxy growth, but we have not been able to detect them unambiguously so far. This study might in fact be the first example of such strong outflows in the epoch of reionization and it confirms the unique capabilities of NIRSpec in allowing detailed studies of quasars at very early times even with modest integration times.