This is so amazing! At a distance of 4 billion light-years, the Hubble is needed to produce an image this good.
The story is more than a little complicated too. Take a look at this video, it goes a long way in helping to explain things especially how gamma-ray measurements of a gravitational lens can be made.
The story from Fermi:
An international team of astronomers, using NASA’s Fermi observatory, has made the first-ever gamma-ray measurements of a gravitational lens, a kind of natural telescope formed when a rare cosmic alignment allows the gravity of a massive object to bend and amplify light from a more distant source.
This accomplishment opens new avenues for research, including a novel way to probe emission regions near supermassive black holes. It may even be possible to find other gravitational lenses with data from the Fermi Gamma-ray Space Telescope.
“We began thinking about the possibility of making this observation a couple of years after Fermi launched, and all of the pieces finally came together in late 2012,” said Teddy Cheung, lead scientist for the finding and an astrophysicist at the Naval Research Laboratory in Washington.