Gravitational Lensing

[ScottS]

I was reading this article in the Mail today and my first thought was "Isn't this already common knowledge", but having read the article again online, it seems that it's a first for a supernova to be lensed in this way.

Anyway, while I understand the basic principle of gravitational lensing, I fail to understand the end result.

Why four images of the supernova?

Shouldn't the image be lensed equally around the foreground galaxy and present as a circle of light?

Can anyone shed any light on (no apologies for the pun - entirely intended) or explain the physics of this phenomenon?

Thanks.

Scott.

[Ags]

There is a whole cluster of galaxies doing the lensing. Its more like frosted glass than a "lens" and there are many slightly different paths the light can take.

[tibbz2]

Basically the lensing is so strong, and the source of the light is a single 'pin point', so it is seen as multiple images rather than a stretched out arc, which is seen with bigger light sources.

Although I'm not an expert, I have no actual knowledge, just what I've picked up

[GeoffE]

These gravitational lenses appear to be rather poorly figured. 

Geoff

[ollypenrice]

These gravitational lenses appear to be rather poorly figured. 

Geoff

To be fair a lot if it's down to collimation. If only these astronomers would take the trouble to get the Earth into the right place before trying to image from it...

Olly

[Tiki]

These gravitational lenses appear to be rather poorly figured. 

 

Geoff

Perhaps these gravitational lenses should be thought of as the ultimate cure for aperture fever:)

[Ags]

With a central obstruction the size of a galaxy, the contrast is very poor.