A quasar-galaxy merger at $z\sim6.2$: black hole mass and quasar properties from the NIRSpec spectrum

Understand

We present JWST/NIRSpec integral field data of the quasar PJ308-21 at $z=6.2342$.

• As shown by previous ALMA and HST imaging, the quasar has two companion sources, interacting with the quasar host galaxy.
• The high-resolution G395H/290LP NIRSpec spectrum covers the $2.87-5.27\ \rm \mu m$ wavelength range and shows the rest-frame optical emission of the quasar with exquisite quality ($S/N\sim 100-400$ per spectral element).
• Based on the H$\beta$ line from the broad line region, we obtain an estimate of the black hole mass $M_{\rm BH,H\beta}\sim 2.7\times 10^{9}\ \rm M_{\odot}$.