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Images for gamma ray study published in Nature
08 October 2014 | Story by NewsroomA paper has been published in Nature which pinpoints the location of gamma rays emitted during a classical nova explosion and may explain their origins. Below are images with captions and credits available to the media:
Caption: The early stage of the classical nova explosion.
Credit: Image courtesy of Bill Saxton: National Science Foundation, Associated Universities, Inc and the National Science Foundation
Caption: The fast-moving polar flow meets the flow from the equatorial region
Credit: Image courtesy of Bill Saxton: National Science Foundation, Associated Universities, Inc and the National Science Foundation
Caption: Towards the end of the process, everything detaches from the binary system
Credit: Image courtesy of Bill Saxton: National Science Foundation, Associated Universities, Inc and the National Science Foundation
Caption: Radio-telescope images of the nova explosion.
Left: In the initial explosion, the nova envelope (the nuclear explosion that encompasses the white dwarf and its nearby companion) expands (the light yellow area). This interacts with the binary system, which you can see right in the middle: a star and a little circle, showing the orbit. The effect is that material in the equatorial region (dark yellow, going vertically in the image) becomes much more dense.
Middle: The dense material (now in yellow) starts moving at a slower velocity, as the material coming out of the poles moves at a much faster velocity (now in blue). This is because there is not much interaction at the poles, so the material can flow smoothly. This difference in velocity is what produces the shocks (orange lines), and the red blobs depict the shocks in the radio emission. The reason we don't see these shocks in other regions is because they are embedded within the ejecta, which is opaque (in the same way that you cannot see through a dense cloud).
Right: At this point the wind from the white dwarf ceases, and everything detaches from the binary system as it flows outward and rapidly drops in density. The blue region will drop in density much faster than the yellow region, which will dominate radio images for much longer.
Credit: Image courtesy of Bill Saxton: National Science Foundation, Associated Universities, Inc and the National Science Foundation
Caption: Dr Valério Ribeiro.
Credit: Bianca Kuck, UCT
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