Quote:
|
Originally Posted by Press Release NRF/SRAO 7 May 2020
A team of astronomers from South Africa and the US have used the MeerKAT telescope to solve a longstanding puzzle in ‘X’-shaped radio galaxies.
Many galaxies far more active than the Milky Way have enormous twin jets of radio waves extending far into intergalactic space. Normally these go in opposite directions, coming from a massive black hole at the centre of the galaxy. However, a few are more complicated and appear to have four jets forming an ‘X’ on the sky.
Several possible explanations have been proposed to understand this phenomenon. These include changes in the direction of spin of the black hole at the centre of the galaxy, and associated jets, over millions of years; two black holes each associated with a pair of jets; and material falling back into the galaxy being deflected into different directions forming the other two arms of the ‘X’.
Exquisite new MeerKAT observations of one such galaxy, PKS 2014-55, strongly favour the latter explanation as they show material “turning the corner” as it flows back towards the host galaxy; the results have just been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.
|
Full press release, images here :-
https://www.sarao.ac.za/media-releas...of-x-galaxies/
Paper at arXiv, "Hydrodynamical Backflow in X-shaped Radio Galaxy PKS 2014-55" by Cotton et. al. :-
https://arxiv.org/pdf/2005.02723.pdf
I didn't realise the scale of this until I saw the disc of the galaxy outline on the photo. 
