Two variable quasars at z<4
Abstract
In this paper we report the discovery of two quasars with redshifts z=4.20 and 4.36 on the basis of optical variability. The quasars were found from digital stacks of a set of about 200 Schmidt telescope plates, which were subdivided into yearly sub-stacks of four plates covering 12 years, giving a limiting magnitude of R=21. The advantages of this technique are discussed, and the properties of the quasars are compared with those found by other methods.
- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 1996
- DOI:
- 10.1093/mnras/280.1.L1
- Bibcode:
- 1996MNRAS.280L...1H
- Keywords:
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- QUASARS: GENERAL