Angelos K
Jan13-12, 12:37 PM
Dear all,
so far I have only studied weak lensing. Therefore I understand little about multiple images.The light paths, by Fermat's principle, have to correspond to stationary points of the (proper) time delay. Minima, maxima saddle points. Basics are nicely reviewed here [p.14]:
Narayan and Bartelmann 1997 (http://www.ita.uni-heidelberg.de/research/bartelmann/Lectures/EinfSeminar/JeruLect.pdf)
My question is why saddle points and maxima correspond to multiple images as for example claimed here [p.11]:
Takahashi et al. 2011 (http://arxiv.org/pdf/1106.3823)
Am I right to assume that each maximum or saddle point creates two images?
All the best,
Angelos
so far I have only studied weak lensing. Therefore I understand little about multiple images.The light paths, by Fermat's principle, have to correspond to stationary points of the (proper) time delay. Minima, maxima saddle points. Basics are nicely reviewed here [p.14]:
Narayan and Bartelmann 1997 (http://www.ita.uni-heidelberg.de/research/bartelmann/Lectures/EinfSeminar/JeruLect.pdf)
My question is why saddle points and maxima correspond to multiple images as for example claimed here [p.11]:
Takahashi et al. 2011 (http://arxiv.org/pdf/1106.3823)
Am I right to assume that each maximum or saddle point creates two images?
All the best,
Angelos