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An international team led by
Chris Riseley have identified a series of rarely observed radio
objects – a radio relic, a radio halo and fossil radio emission –
within a particularly dynamic galaxy cluster called Abell 3266.
The team used new data from the ASKAP radio telescope and the
Australia Telescope Compact Array (ATCA) to study Abell 3266 in
detail. When clusters collide with each other,
huge amounts of energy are put into the particles of the hot plasma,
generating radio emission.
"Fossil" radio sources are the radio leftovers from the death of a
supermassive black hole at the centre of a radio galaxy. When they're
in action, black holes shoot huge jets of plasma far out beyond the
galaxy itself. As they run out of fuel and shut off, the jets begin to
dissipate. The remnants are what we detect as radio fossils.
The radio fossil in Abell 3266, shown above,
is very faint and red, indicating it is ancient.
The cyan arrow points to the galaxy the team
think once powered the fossil, with a central black hole that has long been switched off.
However, the best physical models simply can't fit the data, revealing gaps
in our understanding of how these sources evolve -- gaps that the team are working to fill.
More information is given in
this article in The Conversation.
(Image credit: Christopher Riseley, Università di Bologna)
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