GA-NIFS: The ultra-dense, interacting environment of a dual AGN at z ∼ 3.3 revealed by JWST/NIRSpec IFS^⋆

¹ Centro de Astrobiología (CAB), CSIC-INTA, Departamento de Astrofísica, Cra. de Ajalvir Km. 4, 28850 Torrejón de Ardoz, Madrid, Spain
e-mail: mperna@cab.inta-csic.es
² National Research Council of Canada, Herzberg Astronomy & Astrophysics Research Centre, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada
³ Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
⁴ Cavendish Laboratory – Astrophysics Group, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK
⁵ Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
⁶ Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique de Paris, 98 bis Bd Arago, 75014 Paris, France
⁷ Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
⁸ Cosmic Dawn Center (DAWN), Copenhagen, Denmark Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark
⁹ Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark
¹⁰ Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
¹¹ European Space Agency, c/o STScI, 3700 San Martin Drive, Baltimore, MD 21218, USA
¹² European Space Agency (ESA), European Space Astronomy Centre (ESAC), Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
¹³ INAF – Osservatorio Astrofisco di Arcetri, Largo E. Fermi 5, 50127 Firenze, Italy
¹⁴ European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching, Germany
¹⁵ European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), Eumetsat Allee 1, 64295 Darmstadt, Germany
¹⁶ AURA for European Space Agency, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21210, USA
¹⁷ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany

Received: 14 April 2023
Accepted: 24 August 2023

Abstract

Context. LBQS 0302−0019 is a blue quasar (QSO) at z ∼ 3.3 that hosts powerful outflows and resides in a complex environment consisting of an obscured active galactic nucleus (AGN) candidate and multiple companions, all within 30 kpc in projection.

Aims. We aim to characterise this complex system using JWST NIRSpec Integral Field Spectrograph (IFS) observations obtained as part of the NIRSpec IFS GTO programme “Galaxy Assembly with NIRSpec IFS” (GA-NIFS); these data cover the QSO rest-frame optical emission lines with a spatial resolution of ∼0.1″ and a sampling of 0.05″ (∼380 pc) over a contiguous sky area of ∼3″ × 3″ (23 × 23 kpc²).

Methods. We developed a procedure to correct for the spurious oscillations (or “wiggles”) in NIRSpec single-spaxel spectra caused by the spatial under-sampling of the point spread function. We performed a QSO–host decomposition with the QDEBLEND3D tools. We used multi-component kinematic decomposition of the optical emission line profiles to infer the physical properties of the emitting gas in the QSO environment.

Results. The QSO–host decomposition allows us to identify both a low- and a high-velocity component. The former possibly traces a warm rotating disk with a dynamical mass M_dyn ∼ 10¹¹ M_⊙ and a rotation-to-random motion ratio v_rot/σ₀ ∼ 2. The other kinematic component traces a spatially unresolved ionised outflow with a velocity of ∼1000 km s⁻¹ and an outflow mass rate of ∼10⁴ M_⊙ yr⁻¹. We clearly detect eight companion objects close to LBQS 0302−0019. For two of them, we detect a regular velocity field that likely traces rotating gas, and we infer individual dynamical masses of ≈10¹⁰ M_⊙. Another companion shows evidence of gravitational interaction with the QSO host. Optical line ratios confirm the presence of a second, obscured AGN ∼20 kpc from the primary QSO; the dual AGN dominates the ionisation state of the gas in the entire NIRSpec field of view.

Conclusions. This work has unveiled in unprecedented detail the complex environment of LBQS 0302−0019, which includes its host galaxy, a close obscured AGN, and nine interacting companions (five of which were previously unknown), all within 30 kpc of the QSO. Our results support a scenario where mergers can trigger dual AGN and can be important drivers of rapid early supermassive black hole growth.