That article is rather thin. How far away is it? There appear to be some odd-shaped objects in the background that look like some galaxies from the Hubble Deep

That article is rather thin. How far away is it? There appear to be some odd-shaped objects in the background that look like some galaxies from the Hubble Deep-space images. But HDS is optical, and this is radio. What RF frequencies are represented by the blue-grey haze? That info would make it possible for a layman to speculate about what material was doing the radiating. It does seem mysterious. If that thing's really a million ly across, then it's surely hard to explain. Any event at the centre most probably happened in a galaxy, and I would expect the galaxy itself to have captured most of the energy from the event. Have they tried to look at the central galaxy in optical? Does it look like an watermelon that's been blasted with a 12-bore? So we're talking about an event that occurred 1 million years ago, plus the time light took to get here. Perhaps it's a hugely energetic event that has illuminated and ionised intergalactic gas? But I can't imagine what kind of event that could be (the merger of two black holes doesn't seem to me to be right, but what do I know).