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CSL-1: a chance projection effect or serendipitous discovery of a gravitational lens induced by a cosmic string?

M. Sazhin·G. Longo·J. M. Alcala'·R. Silvotti·G. Covone·O. Khovanskaya·M. Pavlov·M. Pannella·M. Radovich·V. Testa
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Abstract

CSL-1 (Capodimonte--Sternberg--Lens Candidate, No.1) is an extragalactic double source detected in the OAC-DF (Osservatorio Astronomico di Capodimonte - Deep Field). It can be interpreted either as the chance alignment of two identical galaxies at z=0.46 or as the first case of gravitational lensing by a cosmic string. Extensive modeling shows in fact that cosmic strings are the only type of lens which (at least at low angular resolution) can produce undistorted double images of a background source. We propose an experimentum crucis to disentangle between these two possible explanations. If the lensing by a cosmic string should be confirmed, it would provide the first measurements of energy scale of symmetry breaking and of the energy scale of Grand Unified Theory (GUT).

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M. Sazhin, G. Longo, J. M. Alcala', R. Silvotti, G. Covone, O. Khovanskaya, M. Pavlov, M. Pannella, M. Radovich, V. Testa. 2003-02-26. CSL-1: a chance projection effect or serendipitous discovery of a gravitational lens induced by a cosmic string?. https://doi.org/10.1046/j.1365-8711.2003.06568.x

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