Open AccessGravitational lens under perturbations: symmetry of perturbing potentials with invariant caustics
Author(s) -
An Jin H.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.08581.x
Subject(s) - gravitational microlensing , physics , gravitational lens , degeneracy (biology) , strong gravitational lensing , lens (geology) , classical mechanics , gravitational lensing formalism , gravitation , invariant (physics) , azimuth , axial symmetry , symmetry (geometry) , axis of symmetry , rotational symmetry , astrophysics , optics , mathematical physics , geometry , quantum mechanics , redshift , stars , galaxy , mechanics , bioinformatics , mathematics , biology
When the gravitational lensing potential can be approximated by that of a circularly symmetric system affected by weak perturbations, it is found that the shape of the resulting (tangential) caustics is entirely specified by the local azimuthal behaviour of the affecting perturbations. This provides a common mathematical groundwork for understanding problems such as the close–wide ( d ↔ d −1 ) separation degeneracy of binary lens microlensing light curves and the shear–ellipticity degeneracy of quadruple image lens modelling.