Radio Astronomers Uncover Secrets of Supernova Remnant 1987A

An international team of astronomers from Australia and Hong Kong using the Australia Telescope Compact Array has observed the supernova remnant 1987A in unprecedented detail at radio wavelengths

Radio image of the supernova remnant 1987A (ICRAR)

In February 1987 astronomers observing the Large Magellanic Cloud, a nearby dwarf galaxy, noticed the sudden appearance of what looked like a new star. In fact they weren’t watching the beginnings of a star but the end of one and the brightest supernova seen from Earth in the four centuries since the telescope was invented.
In the 25 years since then, the remnant of supernova 1987A has continued to be a focus for astronomers, providing a wealth of information about one of the Universe’s most extreme events.
“Imaging distant astronomical objects like this at wavelengths less than 1 cm demands the most stable atmospheric conditions. For this telescope, these are usually only possible during cooler winter conditions but even then, the humidity and low elevation of the site makes things very challenging,” explained Dr Giovanna Zanardo from the International Centre for Radio Astronomy Research, lead author of a paper accepted for publication in the Astrophysical Journal (arXiv.org version).

Composite image of the supernova remnant 1987A (ICRAR)

Unlike optical telescopes, a radio telescope can operate in the daytime and can peer through gas and dust allowing astronomers to see the inner workings of objects like supernova remnants, radio galaxies and black holes.
“Supernova remnants are like natural particle accelerators, the radio emission we observe comes from electrons spiralling along the magnetic field lines and emitting photons every time they turn. The higher the resolution of the images the more we can learn about the structure of this object,” said co-author Prof Lister Staveley-Smith, also from the International Centre for Radio Astronomy Research.
“Not only have we been able to analyze the morphology of Supernova 1987A through our high resolution imaging, we have compared it to X-ray and optical data in order to model its likely history,” added co-author Prof Bryan Gaensler from the University of Sydney.
The team suspects a compact source or pulsar wind nebula to be sitting in the centre of the radio emission, implying that the supernova explosion did not make the star collapse into a black hole. They will now attempt to observe further into the core and see what’s there.

Bibliographic information: Giovanna Zanardo et al. 2013. High-resolution radio observations of SNR 1987A at high frequencies. Accepted for publication in the Astrophysical Journal; arXiv: 1301.6527

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