Warped spacetime with a surprise “double zoom” has revealed radiation around a distant supermassive black hole, confirming Einstein’s century-old theory of general relativity in action.
The discovery, led by Matus Rybak of Leiden University, emerged during a study of cold gas in the galaxy RXJ1131-1231, located 6 billion light-years away. This galaxy, home to a powerful quasar, became a unique laboratory thanks to gravitational lensing — an effect first predicted in Einstein’s 1915 theory.
Gravitational lensing occurs when a massive object lies between Earth and a distant source. It bends spacetime and alters the path of light, magnifying the background. In RXJ1131-1231’s case, both macrolensing by a galaxy and microlensing by a star worked together, creating a “double zoom.”
While observing RXJ1131-1231 with ALMA, the Atacama Large Millimeter/submillimeter Array in Chile, the team spotted three independent images of the galaxy with fluctuating brightness. This signaled microlensing in action.
“With this double zoom effect, it’s like stacking two magnifying glasses,” Rybak explained. The result was unprecedented clarity of the quasar’s inner regions.
Comparisons between data from 2015 and 2020 revealed flickering radiation in millimeter wavelengths. Normally emitted by calm gas and dust, this unusual radiation suggested something more extreme.
The team concluded that RXJ1131-1231’s quasar is surrounded by a hot, magnetic “corona” — a doughnut-shaped band of material encircling its supermassive black hole.
Already known for their 2008 breakthroughs in microlensing optical light, Rybak’s team has now advanced the field again by demonstrating microlensing in millimeter radiation for the first time.
Future studies will use NASA’s Chandra X-ray telescope to probe magnetic fields and temperature near the black hole. These insights could reshape models of how supermassive black holes shape galaxy evolution.
The findings were published on August 21 in Physical Review Letters.
