Role of the scalar field in gravitational lensing
  A static and circularly symmetric lens characterized by mass and scalar charge parameters is constructed. For the small values of the scalar charge to the mass ratio, the gravitational lensing is qualitatively similar to the case of the Schwarzschild lens; however, for large values of this ratio the lensing characteristics are significantly different. The main features are the existence of two or nil Einstein ring(s) and a radial critical curve, formation of two or four images and possibility of detecting three images near the lens for sources located at relatively large angular positions. Such a novel lens may also be treated as a naked singularity lens. 
K. S. Virbhadra (1-2), D. Narasimha (1), and S. M. Chitre (1) ((1)   Tata Institute of Fundamental Research, India, (2) Univ...