When Black Holes Meet

A Hawaii telescope has produced data that suggests astronomers may soon see two black holes pair and even merge, the first time such a process has been observed.

Researchers believe the two black holes have synchronised and are producing a quasar that cycles from bright to dark and back again.

The data comes from a telescope in Hawaii used for the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1) Medium Deep Survey. It has been imaging the same area every three days over a four year period in the hope of learning more about quasars (pictured). Those are extremely bright and visible lights thought to be created from the energy of mass that falls onto the accretion disc, which is a collection of material that surrounds a black hole.

The astronomers were expecting to find and measure varying and arrhythmic brightnesses over time in each quasar they tracked. However, they found one quasar that followed a pattern repeating every 542 days.

After verifying their observations, the astronomers concluded the most likely explanation is that two galaxies are merging and that each has a black hole. The two black holes are now orbiting so close to one another that they’ve formed a binary, meaning they are gravitationally bound. That in turn means they are absorbing matter in a predictable cycle.

The next step will be to continue watching the space to see if and when the two black holes get so close that they merge. That’s hugely significant as current astrophysics models aren’t able to predict what happens in this final stage, a situation known as the “final parsec problem”.

[Image credit: Artist’s rendering ULAS J1120+0641 by ESO/M. Kornmesser – http://www.eso.org/public/images/eso1122a/. Licensed under CC BY 4.0 via Wikimedia Commons.]