The Largest Black Hole Merger Of All-Time Is Coming, And Soon
“Over in Andromeda, the nearest large galaxy to the Milky Way, a number of unusual systems have been found.
One of them, J0045+41, was originally thought to be two stars orbiting one another with a period of just 80 days.
When additional observations were taken in the X-ray, they revealed a surprise: J0045+41 weren’t stars at all.”
When you look at any narrow region of the sky, you don’t simply see what’s in front of you. Rather, you see everything along your line-of-sight, as far as your observing power can take you. In the case of the Panchromatic Hubble Andromeda Treasury, where hundreds of millions of stars were captured in impressive fashion, background objects thousands of times as distant can also be seen. One of them, J0045+41, was originally thought to be a binary star system that was quite tight: with just an 80 day orbital period. Follow-up observations in the X-ray, however, revealed that it wasn’t a binary star system after all, but an ultra-distant supermassive black hole pair, destined to merge in as little as 350 years. If we build the right observatory in space, we’ll be able to observe the entire inspiral-and-merger process for as long as we like!