View Full Version : 3d view of lensed galaxies

2012-May-13, 11:41 PM
Is it possible to build a 3d view of a galaxy out of multiple perspectives received via lensing?

2012-May-14, 01:01 AM
Possible? or Has it already been done?

I'm not aware of it having been done. Usually I see information about the implied distribution of mass in the lensing (foreground) galaxy. I *do* see what you're suggesting, but I think that the differences in angle that might give you a 3D look will require more angular resolution than we have, or plan to have anytime this century... but I could be wrong.

2012-May-14, 12:24 PM
So far, we don't know any lensing systems with large enough spread among the lines of sight to be useful - the largest cluster lens image splittings sneak up on one arcminute, which doesn't give a very helpful baseline for such lensing masses. The best case for this would be a supermassive black hole in a galactic nucleus, where we might find light sources that are quite close to it, and for which the deflections (and thus "look angles") differ substantially; calculations of how an accretion disk looks if you include deflection of light in its neighborhood become quite bizarre (and a comparably important effect is Doppler boosting of the radiation from the approaching side).

Not quite related, but in some systems we get some 3D information based on the polarization of scattered light; this lets us see that some active galactic nuclei look different from various directions, and gives us a way to see what kinds of stars are centered in dusty disks. Polarimetry has also provided evidence that supernova explosions are not spherically symmetric, something which is now folded into model predictions since we will observe a random distribution of viewing angles.

2012-May-16, 12:34 AM
Is it possible to build a 3d view of a galaxy out of multiple perspectives received via lensing?

Wouldn't 2d be enough? I assume you're asking about a background galaxy being lensed by some foreground object? It's a rather tricky business, and there are "millions" of different lensing configurations, but I imagine that, in principle, the reconstruction of an original image, or group of objects, amounts to a mathematical calculation. An excellent book on this topic is Einstein's Telescope; the hunt for dark matter and dark energy in the Universe, 2010, by Evalyn Gates.