Black hole collapse - ray tracing

[tom.stoer]

I know several raytraycing results for static Schwarzschild black holes, but I have never seen something similar for collapse models like Oppenheimer-Snyder or Vaidya.

Are there reliable raytraycing results showing the effect on light rays from far distant light emitters observed by (far distant) observers?

 

[tom.stoer]

no ideas?

 

[tom.stoer]

push

 

[bcrowell]

What do you mean by raytracing results? Mathematical theorems? Simulated images? Characterizations of possible orbits? The Vaidya metric represents the collapse of a field of incoherent radiation, so I would think that the geodesics would be the same as the trajectories of the infalling matter, which would also be the same as the rays in an optical simulation.

Is this of any interest? Seahra, "An introduction to black holes," http://www.math.unb.ca/~seahra/resources/notes/black_holes.pdf Has a bunch of discussion of horizons in the Vaidya metric.

 

[pervect]

Assuming I'm right in thinking that ray tracing is just null geodesics, the static schwarzschild should be the same as oppenheimer-snyder if you make sure light only passes in the external part of the metric, as the metric is the same.

I'm guessing this may not be particularly helpful, though.

 

[tom.stoer]

Simulated images?

Yes, simulated images; like

http://pasj.asj.or.jp/v57/n3/570315/node4.html
http://www.wissenschaft-online.de/astrowissen/downloads/talks/pdf/RelEmLines.pdf

 

[tom.stoer]

Assuming I'm right in thinking that ray tracing is just null geodesics, the static schwarzschild should be the same as oppenheimer-snyder if you make sure light only passes in the external part of the metric, as the metric is the same.

Yes.

The Schwarzschild portion is growing with t to smaller r(t), therefore the images of rays not crossing r(t) are rays like in Schwarzschild spacetime with smaller r(t) but constant mass M.

But what I am especially interested in is the image of rays
a) passing through the dust ball (assuming that the dust is transparent)
b) close to r(t) in the far future where r(t) → 2M asymptotically

 

[bcrowell]

So realistic simulations of what might be seen through a telescope? I think the studies so far have been studies of the feasibility of resolving the event horizon of Sag A* using infrared. I would be surprised if anyone had tried simulating anything else, because Sag A* is the only realistic prospect for us to resolve.

 

[tom.stoer]

A friend of mine investigated Kerr BHs and accretion discs:

http://www.wissenschaft-online.de/astrowissen/downloads/talks/pdf/RelEmLines.pdf