An anomalous concentration of QSOs around NGC 3079 by E.M. Burbidge, G. Burbidge, H.C. Arp and W.M. Napier - who else? Abstract:
So allowing for the lensing pair there are 20 QSOs in the location, which represent around a one in a million chance. But are there not a million or so (indeed many more) such galaxies?It is shown that there are at least 21 QSOs within 1◦ of the nearby active spiral galaxy NGC3079. Many of them are bright (mag<18) so that the surface density of those closer than 15′ to the galaxy centre is close to 100 times the average in the field. The probability that this is an accidental configuration is shown to be < 10−6. Discovery selection effects and microlensing fail by a large factor to explain the phenomenon, suggesting that the QSOs lie in the same physical space as NGC3079. However, two of them make up the apparently lensed pair 0957+561A, B whose lensing galaxy lies at z=0.355. This problem is discussed in the concluding section.