
doi: 10.1038/285385a0
The hypothesis that the double QSO, 0957 + 561A,B (separation 6 arcs s and z = 1.4) is formed by a gravitational lens1 has found strong support from observations2 suggesting the presence of an intervening giant elliptical galaxy with z ≃ 0.4, separated from component B by <1 arc s. According to the lens hypothesis the flux ratio of the two QSOs should be the same at all wavelengths. Any difference observed should be due only to superposition on component B of emission from the lens galaxy, which is expected to be predominantly in the IR. We report here new photometry at 1.25, 1.6 and 2.2 µm which strengthens the case for lens action and confirms that the lens galaxy is a giant elliptical.
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