The identification of two z3.8 QSOs
in a deep CCD survey

The identification of two z3.8 QSOs
in a deep CCD survey

Ian Smail
Alastair C. Edge
Richard S. Ellis

School of Physics, University of New South Wales, Sydney 2052
Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK
Institute of Astronomy, Madingley Rd, Cambridge CB3 0HA, UK

Abstract:

We present the identifications of two quasars from a deep imaging survey with the Palomar 5.1-m. The survey covers an area of 0.25 sq. degrees around a sample of 10 z=0.2-0.3 luminous X-ray clusters. The QSOs were identified on the basis of their stellar morphologies, relatively blue optical and very red UV-optical colours. The two objects are Q1322+5034 with total magnitudes of B=20.8, I=18.3 and (U-B)>4.7; and Q1722+3211 which has total magnitudes of B=21.8, I=19.7 and (U-B)>3.2. Subsequent spectroscopic observations with the 4.2-m William Herschel Telescope have confirmed the identity of these two sources as QSO at z=3.82 and z=3.73 respectively. Our spectroscopic observations identify a damped Lyman- absorber in the spectrum of Q1322+5034 at z=3.439, as well as a second absorption system at z=2.700 which may either be a single very high column-density damped Lyman- system, or more likely a blend of a number of high column-density absorbers spread over a distance of Mpc.

Keywords: cosmology: observations -- cosmology: early universe -- quasars: clusters - individual A1758; A2261

© Copyright Astronomical Society of Australia 1997