TY - JOUR
T1 - Kiloparsec-scale ALMA Imaging of [Cii] and Dust Continuum Emission of 27 Quasar Host Galaxies at z ∼ 6
AU - Venemans, Bram P.
AU - Walter, Fabian
AU - Neeleman, Marcel
AU - Novak, Mladen
AU - Otter, Justin
AU - Decarli, Roberto
AU - Baados, Eduardo
AU - Drake, Alyssa
AU - Farina, Emanuele Paolo
AU - Kaasinen, Melanie
AU - Mazzucchelli, Chiara
AU - Carilli, Chris
AU - Fan, Xiaohui
AU - Rix, Hans Walter
AU - Wang, Ran
N1 - Publisher Copyright:
© 2020. The American Astronomical Society. All rights reserved..
PY - 2020/12/1
Y1 - 2020/12/1
N2 - We present a study of the [C ii] 158 μm line and underlying far-infrared (FIR) continuum emission of 27 quasar host galaxies at z ∼ 6, traced by the Atacama Large Millimeter/submillimeter Array at a spatial resolution of ∼1 physical kpc. The [C ii] emission in the bright, central regions of the quasars have sizes of 1.0-4.8 kpc. The dust continuum emission is typically more compact than [C ii]. We find that 13/27 quasars (approximately one-half) have companion galaxies in the field, at projected separations of 3-90 kpc. The position of dust emission and the Gaia-corrected positions of the central accreting black holes are cospatial (typical offsets ≲0.″1). This suggests that the central black holes are located at the bottom of the gravitational wells of the dark matter halos in which the quasar hosts reside. Some outliers with offsets of ∼500 pc can be linked to disturbed morphologies, most likely due to ongoing or recent mergers. We find no correlation between the central brightness of the FIR emission and the bolometric luminosity of the accreting black hole. The FIR-derived star formation rate densities (SFRDs) in the host galaxies peak at the galaxies' centers, at typical values between 100 and 1000 M o yr-1 kpc-2. These values are below the Eddington limit for star formation, but similar to those found in local ultraluminous infrared galaxies. The SFRDs drop toward larger radii by an order of magnitude. Likewise, the [C ii]/FIR luminosity ratios of the quasar hosts are lowest in their centers (few ×10-4) and increase by a factor of a few toward the galaxies' outskirts, consistent with resolved studies of lower-redshift sources.
AB - We present a study of the [C ii] 158 μm line and underlying far-infrared (FIR) continuum emission of 27 quasar host galaxies at z ∼ 6, traced by the Atacama Large Millimeter/submillimeter Array at a spatial resolution of ∼1 physical kpc. The [C ii] emission in the bright, central regions of the quasars have sizes of 1.0-4.8 kpc. The dust continuum emission is typically more compact than [C ii]. We find that 13/27 quasars (approximately one-half) have companion galaxies in the field, at projected separations of 3-90 kpc. The position of dust emission and the Gaia-corrected positions of the central accreting black holes are cospatial (typical offsets ≲0.″1). This suggests that the central black holes are located at the bottom of the gravitational wells of the dark matter halos in which the quasar hosts reside. Some outliers with offsets of ∼500 pc can be linked to disturbed morphologies, most likely due to ongoing or recent mergers. We find no correlation between the central brightness of the FIR emission and the bolometric luminosity of the accreting black hole. The FIR-derived star formation rate densities (SFRDs) in the host galaxies peak at the galaxies' centers, at typical values between 100 and 1000 M o yr-1 kpc-2. These values are below the Eddington limit for star formation, but similar to those found in local ultraluminous infrared galaxies. The SFRDs drop toward larger radii by an order of magnitude. Likewise, the [C ii]/FIR luminosity ratios of the quasar hosts are lowest in their centers (few ×10-4) and increase by a factor of a few toward the galaxies' outskirts, consistent with resolved studies of lower-redshift sources.
KW - High-redshift galaxies (734)
KW - Observational cosmology (1146)
KW - Quasars (1319)
KW - Star formation (1569)
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U2 - 10.3847/1538-4357/abc563
DO - 10.3847/1538-4357/abc563
M3 - Article
AN - SCOPUS:85097505614
SN - 0004-637X
VL - 904
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 130
ER -