GB 1508+5714 : a radio-loud quasar with Z = 4.30 and the space density of high-redshift, radio-loud quasars.
GB 1508+5714 : a radio-loud quasar with Z = 4.30 and the space density of high-redshift, radio-loud quasars.
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DOI：
10.1093/mnras/273.1.l63
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发表时间：
1995-02
影响因子：
4.8
通讯作者：
I. Hook;R. McMahon;A. Patnaik;I. Browne;P. Wilkinson;M. Irwin;C. Hazard
中科院分区：
文献类型：
--
作者：
I. Hook;R. McMahon;A. Patnaik;I. Browne;P. Wilkinson;M. Irwin;C. Hazard
We report the discovery of a radio loud quasar with a redshift of 4.30. This object, which is the first radio selected quasar with a redshift greater than four, was discovered during an observational investigation into the evolution of the luminosity function of radio loud quasars. Here we describe results based on a sample of ~300, flat spectrum radio sources with S(5GHz) > 200mJy. In this study, rather than carry out an indiscriminate redshift campaign on all the radio sources, we have used the APM POSS catalogue to preselect a subset of stellar-like optical counterparts with red optical colours. Such a subsample is expected to contain a high fraction of high redshift quasars. 10 of the ~300 sources were selected for follow-up optical spectroscopy and three of these are identified as quasars with redshifts greater than 3.0. One of the radio sources, GB1508+5714, is a quasar with z=4.30 and m(R)~19.
