State-of-the-art models of massive black hole formation postulate that quasars at z > 6 reside in extreme peaks of the cosmic density structure in the early universe. Even so, direct observational evidence of these overdensities is elusive, especially on large scales (≫1 Mpc) as the spectroscopic follow-up of z > 6 galaxies is observationally expensive. Here we present Keck/DEIMOS optical and IRAM/NOEMA millimeter spectroscopy of a z ̃ 6 Lyman-break galaxy candidate originally discovered via broadband selection, at a projected separation of 4.65 physical Mpc (13.94 arcmin) from the luminous z = 6.308 quasar J1030+0524. This well-studied field presents the strongest indication to date of a large-scale overdensity around a z > 6 quasar. The Keck observations suggest a z ̃ 6.3 dropout identification of the galaxy. The NOEMA 1.2 mm spectrum shows a 3.5σ line that, if interpreted as [C II], would place the galaxy at z = 6.318 (i.e., at a line-of-sight separation of 3.9 comoving Mpc assuming that relative proper motion is negligible). The measured [C II] luminosity is 3 × 108 L☉, in line with expectations for a galaxy with a star formation rate ̃15 M☉ yr-1, as inferred from the rest-frame UV photometry. Our combined observations place the galaxy at the same redshift as the quasar, thus strengthening the overdensity scenario for this z > 6 quasar. This pilot experiment demonstrates the power of millimeter-wavelength observations in the characterization of the environment of early quasars

Decarli Roberto, M.M. (2019). Testing the paradigm: First spectroscopic evidence of a quasar-galaxy Mpc-scale association at cosmic dawn. ASTRONOMY & ASTROPHYSICS, 631, 1-5 [10.1051/0004-6361/201936813].

Testing the paradigm: First spectroscopic evidence of a quasar-galaxy Mpc-scale association at cosmic dawn

Brusa Marcella
Membro del Collaboration Group
;
Nanni Riccardo
Membro del Collaboration Group
;
Pensabene Antonio
Membro del Collaboration Group
;
Vignali Cristian
Membro del Collaboration Group
2019

Abstract

State-of-the-art models of massive black hole formation postulate that quasars at z > 6 reside in extreme peaks of the cosmic density structure in the early universe. Even so, direct observational evidence of these overdensities is elusive, especially on large scales (≫1 Mpc) as the spectroscopic follow-up of z > 6 galaxies is observationally expensive. Here we present Keck/DEIMOS optical and IRAM/NOEMA millimeter spectroscopy of a z ̃ 6 Lyman-break galaxy candidate originally discovered via broadband selection, at a projected separation of 4.65 physical Mpc (13.94 arcmin) from the luminous z = 6.308 quasar J1030+0524. This well-studied field presents the strongest indication to date of a large-scale overdensity around a z > 6 quasar. The Keck observations suggest a z ̃ 6.3 dropout identification of the galaxy. The NOEMA 1.2 mm spectrum shows a 3.5σ line that, if interpreted as [C II], would place the galaxy at z = 6.318 (i.e., at a line-of-sight separation of 3.9 comoving Mpc assuming that relative proper motion is negligible). The measured [C II] luminosity is 3 × 108 L☉, in line with expectations for a galaxy with a star formation rate ̃15 M☉ yr-1, as inferred from the rest-frame UV photometry. Our combined observations place the galaxy at the same redshift as the quasar, thus strengthening the overdensity scenario for this z > 6 quasar. This pilot experiment demonstrates the power of millimeter-wavelength observations in the characterization of the environment of early quasars
2019
Decarli Roberto, M.M. (2019). Testing the paradigm: First spectroscopic evidence of a quasar-galaxy Mpc-scale association at cosmic dawn. ASTRONOMY & ASTROPHYSICS, 631, 1-5 [10.1051/0004-6361/201936813].
Decarli Roberto, Mignoli Marco, Gilli Roberto, Balmaverde Barbara, Brusa Marcella, Cappelluti Nico, Comastri, Andrea, Nanni Riccardo, Peca Alessandr...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/734820
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