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

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 spatially extended emission of several emission lines (H$\alpha$, H$\beta$, [OIII], [NII], [SII], HeII), which we use 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 detect 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 AGN-like photoionization conditions, the western companion shows minimal dust extinction, low metallicity ($Z\sim 0.4$ Z${}_{\odot }$), and star-formation driven photoionization. The eastern companion shows higher extinction and metallicity ($Z\sim 0.8$ Z${}_{\odot }$) 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 ($M_{\mathrm{dyn}}>10^{11}$ M${}_{\odot }$), it is still rapidly building up by accreting two relatively massive ($M_{\mathrm{star}}\sim 10^{10}$ M${}_{\odot }$) companion sources. This dataset showcases the power of JWST in exposing the build-up of massive galaxies in the first Gyr of the Universe.

15 pages, 16 figures. Accepted for publication in A&A

References in corpus (48)

• The Host Galaxies and Classification of Active Galactic Nuclei
• CEERS Key Paper I: An Early Look into the First 500 Myr of Galaxy Formation with JWST
• The James Webb Space Telescope Mission
• Two Remarkably Luminous Galaxy Candidates at $z\approx 10-12$ Revealed by JWST
• The evolution of the galaxy UV luminosity function at redshifts z ~ 8-15 from deep JWST and ground-based near-infrared imaging
• JADES NIRSpec Spectroscopy of GN-z11: Lyman-$\alpha$ emission and possible enhanced nitrogen abundance in a $z=10.60$ luminous galaxy
• The Pan-STARRS1 distant z>5.6 quasar survey: more than 100 quasars within the first Gyr of the universe
• GA-NIFS: A massive black hole in a low-metallicity AGN at $z\sim 5.55$ revealed by JWST/NIRSpec IFS
• Emission-line Diagnostics of Low Metallicity AGN
• Rapidly star-forming galaxies adjacent to quasars at redshifts exceeding 6
• Mapping metallicity variations across nearby galaxy disks
• Galaxy Stellar Mass Functions from z~10 to z~6 using the Deepest Spitzer/IRAC Data: No Significant Evolution in the Stellar-to-Halo Mass Ratio of Galaxies in the First Gyr of Cosmic Time
• EIGER I. a large sample of [OIII]-emitting galaxies at $5.3<z<6.9$ and direct evidence for local reionization by galaxies
• The Evolution of the Baryons Associated with Galaxies Averaged over Cosmic Time and Space
• Detection of stellar light from quasar host galaxies at redshifts above 6
• Copious Amounts of Dust and Gas in a z=7.5 Quasar Host Galaxy
• The Kinematics of z ~ 6 Quasar Host Galaxies
• The ultra-dense, interacting environment of a dual AGN at z $\sim$ 3.3 revealed by JWST/NIRSpec IFS
• The X-shooter/ALMA Sample of Quasars in the Epoch of Reionization. II. Black Hole Masses, Eddington Ratios, and the Formation of the First Quasars
• The REQUIEM Survey I: A Search for Extended Ly-Alpha Nebular Emission Around 31 z>5.7 Quasars
• EIGER V. Characterizing the Host Galaxies of Luminous Quasars at $z\gtrsim 6$
• Detecting and Characterizing Young Quasars I: Systemic Redshifts and Proximity Zones Measurements
• Molecular gas in three z~7 quasar host galaxies
• The PHANGS-MUSE Nebula Catalogue
• A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): JWST Reveals a Filamentary Structure around a z=6.61 Quasar
• A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): A First Look at the Rest-frame Optical Spectra of $z>6.5$ Quasars Using JWST
• A JWST/NIRSpec Exploration of the Connection between Ionization Parameter, Electron Density, and Star-Formation-Rate Surface Density in z=2.7-6.3 Galaxies
• GA-NIFS: Black hole and host galaxy properties of two z$\simeq$6.8 quasars from the NIRSpec IFU
• The UNCOVER Survey: A First-look HST+JWST Catalog of Galaxy Redshifts and Stellar Population Properties Spanning $0.2\lesssim z\lesssim 15$
• Near-Infrared Imaging of a z=6.42 Quasar Host Galaxy With the Hubble Space Telescope Wide Field Camera 3
• An ALMA multi-line survey of the ISM in two quasar host-companion galaxy pairs at $z>6$
• Physical constraints on the extended interstellar medium of the z=6.42 quasar J1148+5251: [CII] 158um, [NII] 205um and [OI] 146um observations
• XQR-30: Black Hole Masses and Accretion Rates of 42 z>6 Quasars
• EIGER III. JWST/NIRCam observations of the ultra-luminous high-redshift quasar J0100+2802
• Molecular gas in z~6 quasar host galaxies
• The web of the Giant: spectroscopic confirmation of a Large Scale Structure around the z=6.31 quasar SDSS J1030+0524
• Star Formation and ISM Properties in Host Galaxies of Three Far-infrared Luminous Quasars at $z\sim 6$
• Probing the full CO spectral line energy distribution (SLED) in the nuclear region of a quasar-starburst system at $z=6.003$
• The Close AGN Reference Survey (CARS): IFU survey data and the BH mass dependence of long-term AGN variability
• Limits to Rest-Frame Ultraviolet Emission From Far-Infrared-Luminous z~6 Quasar Hosts
• A quasar-galaxy merger at $z\sim 6.2$: black hole mass and quasar properties from the NIRSpec spectrum
• The Impact of Star-Formation-Rate Surface Density on the Electron Density and Ionization Parameter of High-Redshift Galaxies
• A comprehensive view of the interstellar medium in a quasar host galaxy at z~6.4
• Unveiling hidden active nuclei in MaNGA star-forming galaxies with HeII$\lambda$4686 line emission
• Mapping electron temperature variations across a spiral arm in NGC 1672
• Accurate dust temperature and star formation rate in the most luminous $z>6$ quasar in the HYPerluminous quasars at the Epoch of ReionizatION (HYPERION) sample
• Unveiling the main sequence of galaxies at $z\ge 5$ with the James Webb Space Telescope: predictions from simulations
• Ionized gas metallicity of the strong [OIII]λ emission-line compact galaxies in the LAMOST survey

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