Caustic Curve in Gravitational Lensing/Microlensing?

Question

Can someone explain, in simple words, what a caustic curve is in a Microlensing event and how it is formed? Somehow, I don’t seem to get the concept by reading the definition of such curve. A visual explanation is highly appreciated.

Answer 1

Hi,

at least give us a link of the curve.

Hope this helps.

Answer 2

You are referring to 2 fields in the same breath - Optics, the subject in which 'Caustic' occurs & Gravitational lensing which is an phenomena in astronomy.

In reflection or refraction envelope or projection of a bundle light rays on another solid is 'Caustic'. It also refers to the curve to which the light rays are tangent to, defining its boundary of an envelope as a curve of concentrated light. Put a galss of water on a table, you will observe that a bright network with sharp cusps is formed when light refracts through the water to fall on the table on other side.

Ever since Einstein's discovery that light rays bend towards massive gravitational bodies, a phenomena of bundles of light rays from distant Quasars and such objects arriving at us past massive gravitational bodies, producing multiple images even was oberved (serious work started in 1993). In this microlensing of light rays, 'Caustic' can be observed here and is of relevance.  

Answer 3

Well, before reading this question, I didn't even know what "caustic" was.  And honestly, I'm still not sure, but I have developed a few ideas in the last couple minutes of sleuthing.

Try the links in my (sources) section, hopefully this is waht you are referring to and will at least be slightly helpful.

:/