Discovery of a radio-loud/radio-quiet binary quasar

被引:12
作者
Brotherton, MS
Gregg, MD
Becker, RH
Laurent-Muehleisen, SA
White, RL
Stanford, SA
机构
[1] Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA
[2] Univ Calif Davis, Dept Phys, Davis, CA 95616 USA
[3] Space Telescope Sci Inst, Baltimore, MD 21218 USA
关键词
galaxies : evolution; galaxies : interactions; quasars : emission lines; quasars : general;
D O I
10.1086/311956
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We report the discovery of a small-separation quasar pair (z = 0.586, O = 18.4, 19.2, and a separation of 2 ".3) associated with the radio source FIRST J164311.3+315618 (S(1400) = 120 mJy). The spectrum of the brighter quasar (A) has a much stronger narrow emission line spectrum than the other (B), and it also has stronger Balmer lines relative to the continuum. The continuum ratio of the spectra is flat in the blue (lambda(obs) < 6000 A) at about 2.1 but falls to 1.5 at longer wavelengths. A K' image shows two unresolved sources with a flux ratio of 1.3. The different colors appear to result from the contribution of the host galaxy of B, which is evident from Ca II and high-order Balmer absorption lines that are indicative of a substantial young stellar population. New 3.6 cm VLA observations show that the compact radio source is coincident with quasar A (B is only marginally detected). We rule out the lensing hypothesis because the optical flux ratio is A/B approximate to 1.5-2, while the radio flux ratio is A/B greater than or similar to 40, and conclude that this system is a binary. Moreover, the radio-loud quasar is a compact, steep spectrum source. FIRST J164311.3+315618A, B is the lowest redshift and smallest separation binary quasar yet identified.
引用
收藏
页码:L61 / L64
页数:4
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