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ALMA Observations of Quasar Host Galaxies at z ≃ 4.8

Published version
Peer-reviewed

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Abstract

We present ALMA band-7 data of the [C ii] 157:74 m emission line and underlying far-infrared (FIR) continuum for twelve luminous quasars at z ' 4:8 powered by fast-growing supermassive black holes (SMBHs). Our total sample consists of eighteen quasars, twelve of which are presented here for the rst time. The new sources consists of six Herschel/SPIRE detected systems, which we de ne as "FIR-bright" sources, and six Herschel/SPIRE undetected systems, which we de ne as "FIR-faint" sources. We determine dust masses for the quasars hosts of Mdust 0:2􀀀25:0 108M , implying ISM gas masses comparable to the dynamical masses derived from the [C ii] kinematics. It is found that on average the Mgii line is blueshifted by 500kms􀀀1 with respect to the [C ii] emission line, which is also observed when complementing our observations with data from the literature. We nd that all of our "FIR-bright" subsample and most of the "FIR-faint" objects lie above the main sequence of star forming galaxies at z 5. We detect companion sub-millimeter galaxies (SMGs) for two sources, both FIR-faint, with a range of projected distances of 20 􀀀 60 kpc and with typical velocity shifts of j vj < 200kms􀀀1 from the quasar hosts. Of our total sample of eighteen quasars, 5/18 are found to have dust obscured starforming companions.

Description

Keywords

Active galaxies, High-redshift galaxies, Galaxy interactions, Quasars, Star formation

Journal Title

Astrophysical Journal

Conference Name

Journal ISSN

0004-637X
1538-4357

Volume Title

895

Publisher

Institute of Physics Publishing

Rights

All rights reserved
Sponsorship
Science and Technology Facilities Council (ST/M001172/1)
European Research Council (695671)
ERC; STFC