DES J0454-4448: discovery of the first luminous <i>z</i> ≥ 6 quasar from the Dark Energy Survey

Reed, S. L.; McMahon, R. G.; Banerji, M.; Becker, G. D.; Gonzalez-Solares, E.; Martini, P.; Ostrovski, F.; Rauch, M.; Abbott, T.; Abdalla, F. B.; Allam, S.; Benoit-Levy, A.; Bertin, E.; Buckley-Geer, E.; Burke, D.; Rosell, A. Carnero; da Costa, L. N.; D'Andrea, C.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Cunha, C. E.; Estrada, J.; Evrard, A. E.; Neto, A. Fausti; Finley, D. A.; Fosalba, P.; Frieman, J.; Gruen, D.; Honscheid, K.; James, D.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marshall, J.; Merritt, K.; Miquel, R.; Mohr, J.; Nord, B.; Ogando, R.; Plazas, A.; Romer, K.; Roodman, A.; Rykoff, E.; Sako, M.; Sanchez, E.; Santiago, B.; Schubnell, M.; Sevilla, I.; Smith, C.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Tucker, D.; Walker, A.; Wechsler, R. H.
2015
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
DOI
10.1093/mnras/stv2031
We present the first results of a survey for high-redshift, z >= 6, quasars using izY multicolour photometric observations from the Dark Energy Survey (DES). Here we report the discovery and spectroscopic confirmation of the Z(AB), Y-AB = 20.2, 20.2 (M-1450 = -26.5) quasar DES J0454-4448 with a redshift of z = 6.09 +/- 0.02 based on the onset of the Ly alpha forest and an H I near zone size of 4.1(-1.2)(+1.1) proper Mpc. The quasar was selected as an i-band drop out with i-z = 2.46 and z(AB) < 21.5 from an area of similar to 300 deg(2). It is the brightest of our 43 candidates and was identified for spectroscopic follow-up solely based on the DES i-z and z-Y colours. The quasar is detected by WISE and has W1(AB) = 19.68. The discovery of one spectroscopically confirmed quasar with 5.7 < z < 6.5 and z(AB) <= 20.2 is consistent with recent determinations of the luminosity function at z similar to 6. DES when completed will have imaged -5000 deg2 to Y-AB = 23.0 (5 sigma point source) and we expect to discover 50-100 new quasars with z > 6 including 3-10 with z > 7 dramatically increasing the numbers of quasars currently known that are suitable for detailed studies.