Discovery of a z = 6.1 Radio‐Loud Quasar in the NOAO Deep Wide Field Survey

Abstract

From examination of only 4 deg2 of sky in the NOAO Deep Wide-Field Survey (NDWFS) region, we have identified the first radio-loud quasar at a redshift z > 6. The object, FIRST J1427385+331241, was discovered by matching the FLAMINGOS Extragalactic Survey (FLAMEX) IR survey to Faint Images of the Radio Sky at Twenty cm (FIRST) survey radio sources with NDWFS counterparts. One candidate z > 6 quasar was found, and spectroscopy with the Keck II telescope confirmed its identification yielding a redshift z = 6.12. The object is a broad absorption line (BAL) quasar with an optical luminosity of MB ~ -26.9 and a radio-to-optical flux ratio ~60. Two Mg II absorptions systems are present at redshifts of z = 2.18 and z = 2.20. We briefly discuss the implications of this discovery for the high-redshift quasar population.