An apparent gravitational lens with an image separation of 2.6 arc min

We report here observations which confirm Paczynski's speculation ¹ that the previously known² pair of 19th magnitude quasars 1146 + 111B,C are actually two images of a single object produced by a gravitational lens. The image splitting is 157 arc s, more than 20 times greater than any previously reported³, thus indicating an exceptionally massive lensing object. The data supporting the lens hypothesis are remarkably similar, high signal-to-noise, moderate-resolution spectra of the two components. Both spectra show strong Mg II λ2,798 emission at z = 1.012±0.001 with indistinguishable redshifts (Δv = 126±309 km s^-1), widths (FWHM = 64±4 Å) and detailed profile shapes. Both spectra also show broad troughs at λ6,180 and several weaker continuum features. Neither object exhibits the [O II] λ3,727 line which is frequently strong in Mg II emission objects. If the foreground galaxy clustering apparent in a deep R band charge-coupled device (CCD) image proves insufficient to explain the large image splitting, other possibilities such as massive dark objects (for example, a ∼10¹⁵ M_ȯ black hole) or a cosmic string may be indicated.