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arXiv · 1604.01361

Serendipitous discovery of a projected pair of QSOs separated by 4.5 arcsec on the sky

K. E. Heintz·J. P. U. Fynbo·J. -K. Krogager·M. Vestergaard·P. Møller·M. Arabsalmani·S. Geier·P. Noterdaeme·C. Ledoux·F. G. Saturni·B. Venemans
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Abstract

We present the serendipitous discovery of a projected pair of quasi-stellar objects (QSOs) with an angular separation of $\Delta\theta =4.50$ arcsec. The redshifts of the two QSOs are widely different: one, our programme target, is a QSO with a spectrum consistent with being a narrow line Seyfert 1 AGN at $z=2.05$. For this target we detect Lyman-$\alpha$, \ion{C}{4}, and \ion{C}{3]}. The other QSO, which by chance was included on the spectroscopic slit, is a Type 1 QSO at a redshift of $z=1.68$, for which we detect \ion{C}{4}, \ion{C}{3]} and \ion{Mg}{2}. We compare this system to previously detected projected QSO pairs and find that only about a dozen previously known pairs have smaller angular separation.

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K. E. Heintz, J. P. U. Fynbo, J. -K. Krogager, M. Vestergaard, P. Møller, M. Arabsalmani, S. Geier, P. Noterdaeme, C. Ledoux, F. G. Saturni, B. Venemans. 2016-04-05. Serendipitous discovery of a projected pair of QSOs separated by 4.5 arcsec on the sky. https://doi.org/10.3847/0004-6256/152/1/13

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