JWST’s PEARLS: A

We present JWST NIRSpec integral field spectroscopy observations of the z = 5.89 quasar NDWFS J1425+3254 from 0.6–5.3 μm, covering the rest-frame ultraviolet and optical at a spectral resolution of R ∼ 100. The quasar has a black hole mass of M_BH=(1.4+3.1-1.0)×10⁹ M⊙ and an Eddington ratio of L_Bol/L_Edd=0.3+0.6-0.2, as implied from the broad Balmer Hα and Hβ lines. The quasar host has significant ongoing obscured star formation, as well as a quasar-driven outflow with velocity 6050⁺⁴⁶⁰₋₆₃₀ km s−1 and ionised outflow rate of 1650⁺¹³⁰₋₁₂₃₀ M⊙ yr−1. This is possibly one of the most extreme outflows in the early Universe. The data also reveal that two companion galaxies are merging with the quasar host. The north-eastern companion galaxy is relatively old and very massive, with a luminosity-weighted stellar age of 65⁺⁹₋₄ Myr, stellar mass of (3.6+0.6-0.3)×10¹¹\,M_, and star-formation rate (SFR) of ∼15–30 M⊙ yr−1. A bridge of gas connects this companion galaxy and the host, confirming their ongoing interaction. A second merger is occurring between the quasar host and a much younger companion galaxy to the south, with a stellar age of 6.7 ± 1.8 Myr, stellar mass of (1.9 ± 0.4)×1010 M⊙, and SFR of ∼40–65 M⊙ yr−1. There is also another galaxy in the field, likely in the foreground at z = 1.135, which could be gravitationally lensing the quasar with a magnification of 1 < μ < 2 and, thus, < 0.75 mag. Overall, the system is a ‘train-wreck’ merger of three galaxies, with star formation and extreme quasar activity that were likely triggered by these ongoing interactions.