Letter | Published:

‘Missing image’ in gravitational lens systems?

Naturevolume 321pages4546 (1986) | Download Citation



Gravitational lens models involving extended mass distributions generally predict an odd number of images1, with one of the images close to the centre of the principal lens galaxy. In all the lens systems observed up to now, only an even number of images have been unambiguously detected. A number of suggestions2–4 have been advanced to explain the absence of the ‘odd’ image, but none of these is sufficiently compelling. We suggest here that the presence of a compact nucleus with mass in the range 5 × 109 to 5 × 1010 solar masses (M), contained within a region of size 50 pc at the centre of a lens galaxy, would dim the odd image significantly without affecting the rest of the image configuration.

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  1. Department of Physics, University of Calgary, Calgary, Alberta, Canada, T2N 1N4

    • D. Narasimha
  2. Astronomy Centre, University of Sussex, Brighton, BN1 9QH, UK

    • K. Subramanian
  3. Tata Institute of Fundamental Research, Homi Bhabha Road, Bombay, 400 005, India

    • S. M. Chitre


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