Astronomers find cosmic one-two punch

Washington: By combining data from several telescopes around the world including India’s Giant Metrewave Radio Telescope (GMRT) in Pune, astronomers have discovered a cosmic double whammy unlike any ever seen before.

Two of the most powerful phenomena in the Universe, a supermassive black hole, and the collision of giant galaxy clusters, have combined to create a stupendous cosmic particle accelerator, the researchers reported in the journal Nature Astronomy.

“We have seen each of these spectacular phenomena separately in many places,” said lead researcher Reinout van Weeren of the Harvard-Smithsonian Centre for Astrophysics (CfA) in Cambridge, Massachusetts, US.

“This is the first time, however, that we seen them clearly linked together in the same system,” Weeren noted.

This cosmic double whammy is found in a pair of colliding galaxy clusters called Abell 3411 and Abell 3412 located about two billion light years from Earth.

The two clusters are both very massive, each weighing about a quadrillion or a billion times the mass of the Sun.

This discovery solves a long-standing mystery in galaxy cluster research about the origin of beautiful swirls of radio emission stretching for millions of light years, detected in Abell 3411 and Abell 3412 with the GMRT.

The team determined that as the shock waves travel across the cluster for hundreds of millions of years, the doubly accelerated particles produce giant swirls of radio emission.

“This result shows that a remarkable combination of powerful events generate these particle acceleration factories, which are the largest and most powerful in the Universe,” co-author William Dawson of Lawrence Livermore National Lab in Livermore, California, said.

Besides GMRT, the researchers combined data from NASA’s Chandra X-ray Observatory, the US National Science Foundation’s Karl G. Jansky Very Large Array, and other telescopes to find out what happens when matter ejected by a giant black hole is swept up in the merger of two enormous galaxy clusters.

“It is a bit poetic that it took a combination of the world’s biggest observatories to understand this,” Dawson noted.

“It’s almost like launching a rocket into low-Earth orbit and then getting shot out of the Solar System by a second rocket blast,” co-author Felipe Andrade-Santos, also of the Harvard-Smithsonian Centre for Astrophysics.

“These particles are among the most energetic particles observed in the Universe, thanks to the double injection of energy,” Andrade-Santos explained.