Year: 2024
Type: article
Abstract: We present JWST/NIRSpec integral field spectroscopy in the rest-frame optical bands of the system PJ308–21, a quasar at z = 6.2342 caught as its host galaxy interacts with companion galaxies. We detect the spatially extended emission of several emission lines (Hα, Hβ, [O III], [N II], [S II], and He II), which we used to study the properties of the ionized phase of the interstellar medium: the source and hardness of the photoionizing radiation field, metallicity, dust reddening, electron density and temperature, and star formation. We also marginally detected continuum starlight emission associated with the companion sources. We find that at least two independent satellite galaxies are part of the system. While the quasar host appears highly enriched and obscured, with photoionization conditions typical of an Active Galactic Nucleus, the western companion shows minimal dust extinction, low metallicity (Z ∼ 0.4 Z⊙), and star formation driven photoionization. The eastern companion shows higher extinction and metallicity (Z ∼ 0.8 Z⊙) compared to the western companion, and it is at least partially photoionized by the nearby quasar. We do not find any indication of AGN in the companion sources. Our study shows that while the quasar host galaxy is already very massive (Mdyn > 1011 M⊙), it is still rapidly building up by accreting two relatively massive (Mstar ∼ 1010 M⊙) companion sources. This dataset showcases the power of JWST in exposing the buildup of massive galaxies in the first gigayear of the Universe.
Authors: Roberto Decarli, Federica Loiacono, Emanuele Paolo Farina, Massimo Dotti, Alessandro Lupi, Romain A. Meyer, Marco Mignoli, Antonio Pensabene, Michael A. Strauss, Bram Venemans, Jinyi Yang, Fabian Walter, Julien Wolf, Eduardo Bañados, Laura Blecha, Sarah Bosman, Chris L. Carilli, Andrea Comastri, Thomas Connor, Tiago Costa, Anna-Christina Eilers, Xiaohui Fan, Roberto Gilli, Hyunsung D. Jun, Weizhe Liu, Madeline A. Marshall, Chiara Mazzucchelli, Marcel Neeleman, Masafusa Onoue, Roderik Overzier, Maria Anne Pudoka, Dominik A. Riechers, Hans-Walter Rix, Jan-Torge Schindler, Benny Trakhtenbrot, Maxime Trebitsch, Marianne Vestergaard, Marta Volonteri, Feige Wang, Huanian Zhang, Siwei Zou
Institutions: University of Arizona, Max Planck Institute for Astronomy, University of Florida, Heidelberg University, National Radio Astronomy Observatory, Jet Propulsion Laboratory, Center for Astrophysics Harvard & Smithsonian, Max Planck Institute for Astrophysics, Newcastle University, Massachusetts Institute of Technology, Northwestern College - Iowa, Herzberg Institute of Astrophysics, ARC Centre of Excellence for All-sky Astrophysics, National Research Council Canada, Universidad Diego Portales, University of Cologne, Universität Hamburg, Tel Aviv University, University of Groningen, University of Copenhagen, Centre National de la Recherche Scientifique, Institut d'Astrophysique de Paris, Sorbonne Université, Huazhong University of Science and Technology, Tsinghua University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W6902983427
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