Hawking Radiation w/out black holes

[Pengwuino]

I stumbled upon an article while doing some research that had a statement saying that Hawking radiation can be found in places beyond black hole horizons. This lead me to this paper (which I'm not actually interested in beyond it's reference to the existence of hawking radiation outside of gravity) about observed Hawking Radiation in lasers

http://arxiv.org/abs/1009.4634

So apparently Hawking radiation is not simply confined to black hole horizons. The question I have, however, is if Hawking radiation exists in space-times that do not have astrophysical black holes. For example, can a simple planet exhibit hawking radiation? Also, even if you do have a black hole, does the Hawking temperature only apply to the horizon? That is, can the area an appreciable distance away from the event horizon have a temperature as seen from an observer at infinity?

 

[George Jones]

http://arxiv.org/abs/1009.4634

This isn't a paper about Hawking radiation, it is a paper about analog Hawking radiation. Experimental physicists can't study Hawking radiation from black holes, so they study acoustical systems that have similar properties. In acoustical systems, a black hole analog is a region from which sound waves cannot propagate, and is called a dumb hole. The above paper is about optical systems. A detailed explanation of the paper is given at

http://physics.aps.org/articles/v3/95.

 

[Pengwuino]

Yes, I'm aware, that's why I put the blurb about not being interested in the paper other than the brief mention that Hawking radiation is not something that only ever happens at the event horizon of a black hole.

So my question really truly is about space-time hawking radiation.

 

[bcrowell]

Cool paper! I don't pretend to understand all the optics and condensed-matter physics.

It sounds like what they're studying isn't an analog of a black hole, it's an analog of a white hole. (In GR, they aren't really different things, but I imagine that doesn't apply here.)

Event horizons in GR are much more general than black holes. For example, an accelerated observer has an event horizon: http://www.lightandmatter.com/html_books/genrel/ch06/ch06.html#Section6.1

 

[IsometricPion]

This http://arxiv.org/pdf/hep-th/0106111v1" he uses the term "Hawking-like flux".