Some astrophysical processes are so slow that we only see a snapshot of what’s happing and it is up to astronomers to work out the full movie from it.

In the case of galaxy IC 2497, to help with its reconstruction the researchers had the help of a bubble of gas and a large green blob. The study, published in the Monthly Notices of the Royal Astronomical Society, used a new X-ray view of the galaxy to uncover the active past of its supermassive black hole.

IC 2497 became famous in the astronomy world for sporting a curious little green blob, discovered by Dutch school teacher Hanny van Arkel thanks to a citizen science project, Galaxy Zoo. The blob is called Hanny’s Voorwerp (Dutch for ‘Hanny’s object’) and the international team believes it’s the delayed response from a powerful emission from the supermassive black hole.

If the black hole at the center of IC 2497 was growing at a faster rate until 200,000 years ago, it might explain the glow in the distant blob. The voorwerp is like an after image of a cosmic flash.

The latest observation shows that the supermassive black hole is not dormant yet and probably just got quieter. The clue for this is in the bubble of gas that surrounds the center of the galaxy.

The astronomers were able to estimate the temperature of the gas and it is remarkably cool. When materials fall into supermassive black holes, the gravitational forces heat it up and it begins to emit a lot of light. The light is powerful enough to push gas and dust into intergalactic space forming large spectacular jets.

The team believes the supermassive black hole was in a quasar phase and it was emitting so much energy that it pushed most of the hot gas out, and is now left with the cool gas. Without the hot gas, the supermassive black hole has lost its food source and is slowly going back to sleep.

Understanding all this from a snapshot is definitely not bad.