Defocusing gravitational microlensing

Abstract

We introduce the notion of defocusing gravitational lens considering a MACHO located behind a light source with respect to an observer. The consequence of defocusing effect is a temporal variability of star luminosity which produces a gap instead of a peak as tell--tale signature in the light curve. General theory of (de)focusing rays (geodesics) in a gravitational field is presented. Furthermore, we give estimations of the mass of the lens and the optical depth connected to such a phenomenon.

19 pages, latex, submitted to Physica Scripta

References in corpus (2)

• Possible Gravitational Microlensing of a Star in the Large Magellanic Cloud
• The MACHO Project First Year LMC Results: The Microlensing Rate and the Nature of the Galactic Dark Halo

Cited by in corpus (3)

• Strong field limit analysis of gravitational retro-lensing
• The galactic center black hole as a possible retro-lens for the S2 orbiting star
• A kinematical approach to gravitational lensing using new formulae for refractive index and acceleration