Reed, SL;
Banerji, M;
Becker, GD;
Hewett, PC;
Martini, P;
McMahon, RG;
Pons, E;
... Vikram, V; + view all
(2019)
Three new VHS-DES quasars at 6.7 < z < 6.9 and emission line properties at z > 6.5.
Monthly Notices of the Royal Astronomical Society
, 487
(2)
pp. 1874-1885.
10.1093/mnras/stz1341.
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Abstract
We report the results from a search for z > 6.5 quasars using the Dark Energy Survey (DES) Year 3 data set combined with the VISTA Hemisphere Survey (VHS) and WISE All-Sky Survey. Our photometric selection method is shown to be highly efficient in identifying clean samples of high-redshift quasars, leading to spectroscopic confirmation of three new quasars – VDES J0244−5008 (z = 6.724), VDES J0020−3653 (z = 6.834), and VDES J0246−5219 (z = 6.90) – which were selected as the highest priority candidates in the survey data without any need for additional follow-up observations. We have obtained spectroscopic observations in the near-infrared for VDES J0244−5008 and VDES J0020−3653 as well as our previously identified quasar, VDES J0224−4711 at z = 6.50 from Reed et al. We use the near-infrared spectra to derive virial black hole masses from the full width at half-maximum of the Mg II line. These black hole masses are ≃1–2 × 109 M⊙. Combined with the bolometric luminosities of these quasars of Lbol ≃ 1–3 × 1047, these imply that the Eddington ratios are high, ≃0.6–1.1. We consider the C IV emission line properties of the sample and demonstrate that our high-redshift quasars do not have unusual C IV line properties when compared to carefully matched low-redshift samples. Our new DES + VHS z > 6.5 quasars now add to the growing census of luminous, rapidly accreting supermassive black holes seen well into the epoch of reionization.
| Type: | Article |
|---|---|
| Title: | Three new VHS-DES quasars at 6.7 < z < 6.9 and emission line properties at z > 6.5 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stz1341 |
| Publisher version: | https://doi.org/10.1093/mnras/stz1341 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | galaxies: active, galaxies: formation, galaxies: high-redshift, dark ages, reionization, first stars, quasars: individual: VDES J0224−4711, quasars: individual: VDES J0244−5008, quasars: individual: VDES J0020−3653, quasars: individual: VDES J0246−5219 |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10079189 |
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