Candidate QSOs for spectroscopic confirmation have been identified by colour selection techniques from digital scans of wide-field photographic plates taken with the UK Schmidt Telescope. Plates in the ultra-violet (u), blue (b) and red (r) bands were used, allowing selection by u-b and b-r colours. Candidates were also required to show stellar image profiles on the blue plate and are magnitude limited at b<20·85.
Above is a picture of the UBR input catalogue. A paper detailing the properties and creation of the data set is in preparation, but for the time being, a brief discussion of the catalogue may be found in some of our other publications.
Also available is a map of the survey sky coverage showing how the two survey strips are arranged on the sky and the positions of all previously known QSOs.
Observational experience has shown that over 50% of the candidates really are QSOs. We have a plot showing the catalogue contamination as a function of colour.
If you are interested in using this data set for your own research, keep an eye on this site. We plan to make the catalogue available in the near future.
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(Thu 19 Jun 2008 10:26:28 PDT by RJS)
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