COSMOLOGY, COSMOMICROPHYSICS AND GRAVITATION
We derive approximate formulas for the coordinates and magnification of critical images of a point source in a vicinity of a cusp caustic arising in the gravitational lens mapping. In the lowest (zero-order) approximation, these formulas were obtained in the classical work by Schneider&Weiss (19...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Odessa I. I. Mechnykov National University
2013-11-01
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| Series: | Odessa Astronomical Publications |
| Online Access: | http://oap.onu.edu.ua/article/view/82486 |
| Summary: | We derive approximate formulas for the coordinates and magnification of critical images of a point source in a vicinity of a cusp caustic arising in the gravitational lens mapping. In the lowest (zero-order) approximation, these formulas were obtained in the classical work by Schneider&Weiss (1992) and then studied by a number of authors; first-order corrections in powers of the proximity parameter were treated by Congdon, Keeton and Nordgren. We have shown that the first-order corrections are solely due to the asymmetry of the cusp. We found expressions for the second-order corrections in the case of general lens potential and for an arbitrary position of the source near a symmetric cusp. Applications to a lensing galaxy model represented by a singular isothermal sphere with an external shear y are studied and the role of the second-order corrections is demonstrated. |
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| ISSN: | 1810-4215 |