Caustics in gravitational lensing by mixed binary systems. (arXiv:2007.15119v1 [gr-qc])

<a href="http://arxiv.org/find/gr-qc/1/au:+Bozza_V/0/1/0/all/0/1">Valerio Bozza</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Pietroni_S/0/1/0/all/0/1">Silvia Pietroni</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Melchiorre_C/0/1/0/all/0/1">Chiara Melchiorre</a>

We investigate binary lenses with $1/r^n$ potentials in the asymmetric case

with two lenses with different indexes $n$ and $m$. These kinds of potentials

have been widely used in several contexts, ranging from galaxies with halos

described by different power laws to lensing by wormholes or exotic matter. In

this paper, we present a complete atlas of critical curves and caustics for

mixed binaries, starting from the equal-strength case, and then exploring

unequal-strength systems. We also calculate the transitions between all

different topology regimes. Finally we find some useful analytic approximations

for the wide binary case and for the extreme unequal-strength case.

We investigate binary lenses with $1/r^n$ potentials in the asymmetric case

with two lenses with different indexes $n$ and $m$. These kinds of potentials

have been widely used in several contexts, ranging from galaxies with halos

described by different power laws to lensing by wormholes or exotic matter. In

this paper, we present a complete atlas of critical curves and caustics for

mixed binaries, starting from the equal-strength case, and then exploring

unequal-strength systems. We also calculate the transitions between all

different topology regimes. Finally we find some useful analytic approximations

for the wide binary case and for the extreme unequal-strength case.

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