The merging system is approximately 500 million light-years away, near the constellation of the Dolphin.
Astronomers from an international team used the James Webb Space Telescope to identify, for the first time, the precise location of a powerful source of energy, hidden by cosmic dust, in the bright merging galaxy IIZw096. The interesting ‘engine’ had gone undetected for 12 years to observations with ultraviolet or visible light made by the Hubble Space Telescope. Strangely, it was located outside the main area of the colliding galaxies, they reported Monday.
The power of the webb
“The James Webb Space Telescope has given us completely new views of the universe thanks to its highest spatial resolution and infrared sensitivity ever seen,” said lead author Hanae Inami, a professor at Hiroshima University in Japan.
“We wanted to find the ‘engine’ that drives this galaxy merging system. We knew this source was deeply hidden by cosmic dust, so we couldn’t use visible or ultraviolet light to find it. only in the mid-infrared […] we now see this source dwarfing everything else in these merging galaxies,” explained Hanae Inami.
The intriguing location of the invisible engine
According to one of the co-authors, Thomas Bohn, also from Hiroshima University, the energy of IIZw096 is confined to only a very small fraction of space, about 570 light-years, relative to the 65,000 light-years in diameter of the fusion system. This powerful engine is responsible for most of the mid-infrared emission, which accounts for up to 70% of the system’s total infrared emission. The results of this study were published in The Astrophysical Journal Letters.
“It is intriguing that this compact source, far from the galactic centers, dominates the infrared luminosity of the system,” Bohn stressed. According to him, this source makes a significant contribution to the merger of galaxies, despite being on the outskirts, like a pinch of pepper in the white of a fried egg.
“We want to know what powers this source: is it a starburst or a massive black hole?” Inami wonders. “We will use infrared spectra taken with the James Webb Space Telescope to investigate it. It’s also unusual for the ‘engine’ to be outside the main parts of merging galaxies.so we will explore how this powerful source ended up there.”
A surprisingly dynamic place
For his part, co-author Jason Surace, from the California Institute of Technology, in the US, said the finding supports knowledge about how the universe changes. “The last few decades, prompted by new observations in the infrared, […] have shown that the universe is an amazingly dynamic and violently changing place,” said Surace. “In times past, it was thought that galaxies, the largest things we know of, they just rotated essentially unchanged, like celestial temples in the heavens“, accurate.