Our Australia Telescope Compact Array on Gomeroi Country has helped uncover clues about strange intergalactic blue flashes. These cosmic flashes are so bright, they’re visible from billions of light-years away.
Along with images from other ground-based telescopes and space telescopes, researchers now think these blue flashes are caused by huge black holes tearing an entire star apart in just a few days.
To do this, these black holes have to be big – about 100 times more massive than our Sun.
While black holes this big are known to exist, they’ve never been directly observed. How they grow to that size is still a mystery, but research into these blue flashes could shed light on the stellar environment in which large black holes evolve.
X-ray and optical data of a luminous fast blue optical transient (LFBOT) named AT 2024wpp. Credit: NASA/CXC/UC Berkeley/Nayana A.J et al. (X-ray); Legacy Survey/DECaLS/BASS/MzLS (Optical); NASA/CXC/SAO/P. Edmonds and N. Wolk (Image Processing).
This study included three X-ray telescopes, NASA’s Chandra X-ray Observatory, Swift-XRT and the Nuclear Spectroscopic Telescope Array (NuSTAR); radio telescopes such as ATCA and the Atacama Large Millimeter/submillimeter Array (ALMA); the Ultra-Violet/Optical Telescope (UVOT) on NASA’s Neil Gehrels Swift Observatory; and ground-based optical telescopes, including the Keck, Lick and Gemini Observatories.
All telescopes pointed to AT 2024wpp, the most luminous fast blue optical transient (LFBOT) ever observed. These rare, brief, and intensely bright blue outbursts have puzzled researchers for a decade, but the extreme brightness and detailed multiwavelength data from AT 2024wpp show that they cannot be explained by any kind of normal stellar explosion such as a supernova.
Instead, the new observations indicate that AT 2024wpp was powered by an extreme tidal disruption event caused by the interaction of a large black hole and a companion star. As parts of the disintegrating star crashed into material the black hole had previously stripped and stored in its surroundings, it produced intense blue, ultraviolet, X-ray, and radio emission, with jets launched at roughly 40 percent of the speed of light. This result offers a new way to probe how intermediate-mass black holes grow and interact with nearby massive stars in active star-forming galaxies.
By bringing together data from telescopes and partner observatories around the world, the AT 2024wpp campaign demonstrates how coordinated, rapid-response observations can unravel the physics behind the brightest and most fleeting explosions in the universe.
This information was adapted from news shared by UC Berkeley, the Chandra X-ray Center, NRAO and the Keck Observatory.