A new apparent quasar pair: Q2225-403A,B

We report the serendipitous discovery of a previously unknown quasar at 10.5 from Q2225-403 (z = 2.410). The observation of the broad emission line of Mg iiλ2798 and of the surrounding Fe ii multiplets indicates that the companion quasar is at z = 0.932. The spectrum of Q2225-403 shows a number of absorption lines, the most noteworthy is the Mg ii line at the same redshift of the companion, suggesting that we are probing the gas within the halo ∼ 80 kpc from the closer quasar. From high resolution NIR images we were able to resolve the host galaxies of the two quasars. Basing on the known surface density of quasars in the 2dF survey we estimate that the probability of finding such a close pair is ∼ < 1 per cent.