What is a peryton? It is a bit hard to find an accessible explanation online. I find the word "peryton" in some papers about radio astronomy, here's one example:
http://arxiv.org/abs/1503.05245
I don't think they refer to that French artists' stag with bird's wings that the wikipedia article with the same title is about. (But who knows, maybe the universe is stranger than we can imagine.) What is a peryton in physics? And please don't say "a million perygram".
 A: A paper came out this week pointing to them having a banal (if amusing) origin: they are from two 27 year old microwave ovens. When people get impatient and open the door before the timer runs down, a short burst from the ovens' magnetron is released, which appears as a peryton if the telescope is pointed in the right direction.
Figure 7. shows the perytons clustering around local lunchtime.
http://arxiv.org/pdf/1504.02165v1.pdf
A: I got a translation of the article from the German Wikipedia. Here's an excerpt:

Perytons are in radio astronomy short radio signals having a length of a few milliseconds, which probably terrestrial are origin. The Perytons are named after mythical creatures .
In radio astronomy, terrestrial are noise is always a problem. A well-known noise signal are millisecond bursts of radio emission after a mythological hybrid creatures are called Perytons. Probably these signals are sidelobes captured the antenna. The Perytons occur at high altitudes above the horizon and show no frequency dispersion in contrast to the closely related radio bursts Fast . Perytons often occur as a result of periodic bursts. As a generation mechanisms are recombination of charge carriers three or synchrotron radiation of a collapsing magnetic field are discussed.

They can apparently come from aircraft, atmospheric phenomenon or solar radiation.
This paper and this paper go into more detail.
A: This paper describes them.
http://www.ursi.org/proceedings/procGA11/ursi/GP2-41.pdf
They were apparently given a new name because their origin was uncertain.
A: More on the perytons being caused by microwave ovens being opened while still operating. The microwave oven's magnetron is still generating the microwaves when the door is open before the timer has stopped the microwave.
Article:
http://phenomena.nationalgeographic.com/2015/04/10/rogue-microwave-ovens-are-the-culprits-behind-mysterious-radio-signals
Study:
http://arxiv.org/abs/1504.02165
