Slide 5
Slide 5 text
Deflecting Mass
The deflecting mass may be viewed as an optical thin lens, made up of a two dimensional
mass distribution.
M =
R2
Σ(ξ )
ξ − ξ
|ξ − ξ |2
d2ξ (2)
where
Σ = surface density
R2 = surface area
If the deflecting mass, is perfectly symmetric, the deflection angle becomes
α =
4GM(< ξ)ξ
c2|ξ|2
(3)
Michael Papasimeon Gravitational Lensing 29 October 1998 5 / 34