Radio structure of the ‘double quasar’ 4C11.50

Abstract

WAMPLER et al.¹ have recently announced the discovery of a close pair of optical quasars associated with the radio source 4C11.50. The brighter quasar (a) has a redshift of 0.436, whereas its companion (b), 4.8 arc s away in position angle 95°, has a much larger redshift of 1.901. The statistical probability of a chance coincidence is small and this has led to speculation that, despite the discordant redshifts and the lack of any visible connection, the objects may be physically associated. Hazard et al.² report unpublished observations from Cambridge and Westerbork which suggest that the radio structure is double, with one component coincident with quasar a. Here, we investigate further the alignment of the radio structure, seeking in particular any evidence of a radio connection between the two optical quasars.