A quasar-galaxy merger at $z\sim 6.2$: rapid host growth via accretion of two massive satellite galaxies

• DOI: 10.48550/arxiv.2406.06697
• Publication Date: 2024-06-10
• Authors: Roberto Decarli; F. Loiacono; Emanuele Paolo Fa...; Massimo Dotti; Alessandro Lupi; R. A. Meyer; M. Mignoli; Antonio Pensabene; Michael A. Strauss; Bram Venemans; Jinyi Yang; Fabian Walter; J. Wolf; Eduardo Bañados; Laura Blecha; Sarah E. I. Bosman; C. L. Carilli; A. Comastri; Thomas Connor; Tiago Costa; Anna–Christina Ei...; Xiaohui Fan; R. Gilli; Hyunsung D. Jun; Weizhe Liu; Madeline A. Marshall; Chiara Mazzucchelli; Marcel Neeleman; Masafusa Onoue; Roderik Overzier; Maria Pudoka; Dominik A. Riechers; Hans‐Walter Rix; Jan–Torge Schindler; Benny Trakhtenbrot; Maxime Trebitsch; M. Vestergaard; Marta Volonteri; Feige Wang; Huanian Zhang; Siwei Zou
• Keywords: Satellite galaxy

We present JWST/NIRSpec Integral Field Spectroscopy in the rest-frame optical bands of system PJ308-21, a quasar at $z=6.2342$ caught as its host galaxy interacts with companion galaxies. detect spatially extended emission several lines (H$\alpha$, H$\beta$, [OIII], [NII], [SII], HeII), which we use to study properties ionized phase interstellar medium: source and hardness photoionizing radiation field, metallicity, dust reddening, electron density temperature, star formation. also marginally continuum starlight associated sources. find that least two independent satellite galaxies are part system. While appears highly enriched obscured, AGN-like photoionization conditions, western shows minimal extinction, low metallicity ($Z\sim0.4$ Z$_\odot$), star-formation driven photoionization. The eastern higher extinction ($Z\sim0.8$ Z$_\odot$) compared companion, it is partially photoionized by nearby quasar. do not any indication AGN Our while already very massive ($M_{\rm dyn}>10^{11}$ M$_\odot$), still rapidly building up accreting relatively star}\sim 10^{10}$ M$_\odot$) This dataset showcases power JWST exposing build-up first Gyr Universe.