Discovery of Eight z ~ 6 Quasars from Pan-STARRS1

Bañados, E.; Venemans, B.P.; Morganson, E.; Decarli, R.; Walter, F.; Chambers, K.C.; Rix, H.-W.; Farina, E.P.; Fan, X.; Jiang, L.; McGreer, I.; De Rosa, G.; Simcoe, R.; Weiß, A.; Price, P.A.; Morgan, J.S.; Burgett, W.S.; Greiner, J.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E.A.; Metcalfe, N.; Stubbs, C.W.; Sweeney, W.; Tonry, J.L.; Wainscoat, R.J.; Waters, C.

Abstract

High-redshift quasars are currently the only probes of the growth of supermassive black holes and potential tracers of structure evolution at early cosmic time. Here we present our candidate selection criteria from the Panoramic Survey Telescope & Rapid Response System 1 and follow-up strategy to discover quasars in the redshift range 5.7 lsim z lsim 6.2. With this strategy we discovered eight new 5.7 ≤ z ≤ 6.0 quasars, increasing the number of known quasars at z > 5.7 by more than 10%. We additionally recovered 18 previously known quasars. The eight quasars presented here span a large range of luminosities (–27.3 ≤ M 1450 ≤ –25.4; 19.6 ≤ z P1 ≤ 21.2) and are remarkably heterogeneous in their spectral features: half of them show bright emission lines whereas the other half show a weak or no Lyα emission line (25% with rest-frame equivalent width of the Lyα +N V line lower than 15 Å). We find a larger fraction of weak-line emission quasars than in lower redshift studies. This may imply that the weak-line quasar population at the highest redshifts could be more abundant than previously thought. However, larger samples of quasars are needed to increase the statistical significance of this finding.

Citation

Bañados, E., Venemans, B., Morganson, E., Decarli, R., Walter, F., Chambers, K., …Waters, C. (2014). Discovery of Eight z ~ 6 Quasars from Pan-STARRS1. Astronomical Journal, 148(1), Article 14. https://doi.org/10.1088/0004-6256/148/1/14

• Journal Article Type: Article
• Acceptance Date: Apr 19, 2014
• Publication Date: Jul 1, 2014
• Deposit Date: Jun 16, 2015
• Publicly Available Date: Jun 30, 2015
• Journal: Astronomical Journal
• Print ISSN: 0004-6256
• Electronic ISSN: 1538-3881
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 148
• Issue: 1
• Article Number: 14
• DOI: https://doi.org/10.1088/0004-6256/148/1/14
• Keywords: Cosmology: observations, Quasars: emission lines, Quasars: general, Surveys.