TY - JOUR
T1 - A quasar-galaxy merger at z ~ 6.2
T2 - Rapid host growth via the accretion of two massive satellite galaxies
AU - Decarli, Roberto
AU - Loiacono, Federica
AU - Farina, Emanuele Paolo
AU - Dotti, Massimo
AU - Lupi, Alessandro
AU - Meyer, Romain A.
AU - Mignoli, Marco
AU - Pensabene, Antonio
AU - Strauss, Michael A.
AU - Venemans, Bram
AU - Yang, Jinyi
AU - Walter, Fabian
AU - Wolf, Julien
AU - Bañados, Eduardo
AU - Blecha, Laura
AU - Bosman, Sarah
AU - Carilli, Chris L.
AU - Comastri, Andrea
AU - Connor, Thomas
AU - Costa, Tiago
AU - Eilers, Anna Christina
AU - Fan, Xiaohui
AU - Gilli, Roberto
AU - Jun, Hyunsung D.
AU - Liu, Weizhe
AU - Marshall, Madeline A.
AU - Mazzucchelli, Chiara
AU - Neeleman, Marcel
AU - Onoue, Masafusa
AU - Overzier, Roderik
AU - Pudoka, Maria Anne
AU - Riechers, Dominik A.
AU - Rix, Hans Walter
AU - Schindler, Jan Torge
AU - Trakhtenbrot, Benny
AU - Trebitsch, Maxime
AU - Vestergaard, Marianne
AU - Volonteri, Marta
AU - Wang, Feige
AU - Zhang, Huanian
AU - Zou, Siwei
N1 - Publisher Copyright:
© The Authors 2024.
PY - 2024/9/1
Y1 - 2024/9/1
N2 - 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.
AB - 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.
KW - Galaxies: ISM
KW - Galaxies: high-redshift
KW - Galaxies: star formation
KW - Quasars: individual: PJ308- 21
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UR - http://www.scopus.com/inward/citedby.url?scp=85204309960&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/202449239
DO - 10.1051/0004-6361/202449239
M3 - Article
AN - SCOPUS:85204309960
SN - 0004-6361
VL - 689
JO - Astronomy and astrophysics
JF - Astronomy and astrophysics
M1 - A219
ER -