* Astronomy

Title: Discovery of a Colour-Selected Quasar at z=5.50
Authors: Daniel Stern (1), Hyron Spinrad (2), Peter Eisenhardt (1), Andrew J. Bunker (3), Steve Dawson (2), S. A. Stanford (4 and 5), Richard Elston (6) ((1) JPL/Caltech, (2) UC-Berkeley, (3) IoA, Cambridge, (4) UC-Davis, (5) IGPP/LLNL, and (6) Florida)
(Submitted on 17 Feb 2000)

We present observations of RD J030117+002025, a quasar at z=5.50 discovered from deep, multi-colour, ground-based observations covering 74 square arcmin. This is the most distant quasar or AGN currently known. The object was targeted as an R-band dropout, with R(AB)>26.3 (3-sigma limit in a 3 arcsec diameter region), I(AB)=23.8, and z(AB)=23.4. The Keck/LRIS spectrum shows broad Lyman-alpha/NV emission and sharp absorption decrements from the highly-redshifted hydrogen forests. The fractional continuum depression due to the Lyman-alpha forest is D(A)=0.90. RD J030117+002025 is the least luminous, high-redshift quasar known (M(B)~-22.7).

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