Astronomers have observed a rare and violent cosmic collision between two galaxies, witnessing the piercing effect of radiation on one galaxy’s ability to form new stars. The study, published in Nature, reveals the devastating impact of quasar radiation on the internal structure of gas clouds in a regular galaxy.
Researchers combined observations from the European Southern Observatory’s Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA) to study this phenomenon. The “cosmic joust” system is 11 billion years old, with light reaching Earth only recently, offering a glimpse into the universe’s past.
The quasar at the center of the collision uses supermassive black holes to release huge amounts of radiation, piercing its opponent and disrupting gas clouds. This radiation damps the wounded galaxy’s ability to form new stars, leaving behind smaller, denser regions that are unlikely capable of star formation.
As the galaxies merge, new reserves of fuel are brought within reach of the black hole powering the quasar, allowing it to continue its attack. The study suggests a deeper understanding of the evolution of quasars and their impact on host and nearby galaxies is needed, with future telescopes like ESO’s Extremely Large Telescope poised to provide further insights.
Source: https://phys.org/news/2025-05-cosmic-joust-astronomers-pair-galaxies.html