Three new VHS-DES quasars at 6.7 < z < 6.9 and emission line properties at z > 6.5

Reed, S. L.; Banerji, M.; Becker, G. D.; Hewett, P. C.; Martini, P.; McMahon, R. G.; Pons, E.; Rauch, M.; Abbott, T. M. C.; Allam, S.; Annis, J.; Avila, S.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; De Vicente, J.; Desai, S.; Diehl, H. T.; Doel, P.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Garcia-Bellido, J.; Gaztanaga, E.; Grün, D.; Gschwend, J.; Gutierrez, G.; Hollowood, D. L.; Honscheid, K.; Hoyle, B.; James, D. J.; Kühn, K.; Lahay, O.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Miquel, R.; Ogando, R. L. C.; Plazas, A. A.; Roodman, A.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Serrano, S.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Tucker, D. L. und Vikram, V. (2019): Three new VHS-DES quasars at 6.7 < z < 6.9 and emission line properties at z > 6.5. In: Monthly Notices of the Royal Astronomical Society, Bd. 487, Nr. 2: S. 1874-1885

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 J0224-471 1 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 similar or equal to 1-2 x 10(9) M-circle dot. Combined with the bolometric luminosities of these quasars of L-bot similar or equal to 1-3 x 10(47), these imply that the Eddington ratios are high, similar or equal to 0.6-1.1. We consider the C iv emission line properties of the sample and demonstrate that our highredshift 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.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 0035-8711
• Sprache: Englisch