Hyperluminous infrared galaxies are the rarest and most extreme star-forming systems and found only in the distant Universe.
Stellar, cold-gas and ionized-gas emission distributions of the rare HyLIRG Einstein ring, PJ0116-24. Image credit: Liu et al., doi: 10.1038/s41550-024-02296-7.
“Hyperluminous infrared galaxies (HyLIRGs) are incredibly bright galaxies, lit up by the extremely rapid star formation within them,” said Dr. Daizhong Liu of the Max-Planck Institute for Extraterrestrial Physics and colleagues.
“Previous studies suggested that such extreme galaxies must result from galaxy mergers.”
“These galaxy collisions are thought to create dense gas regions in which rapid star formation is triggered.”
“But isolated galaxies could also become HyLIRGs via internal processes alone, if star-forming gas is rapidly funneled towards the galaxy’s center.”
In their new study, the astronomers focused on a gravitationally lensed HyLIRG galaxy known as PJ0116-24.
“PJ0116-24 is so far away that its light took about 10 billion years to reach us,” they said.
“Luckily, a foreground galaxy acted as a gravitational lens, bending and magnifying the light of PJ0116-24 behind it into the Einstein ring.”
“This precise cosmic alignment allows us to zoom in on very distant objects and see them in a level of detail that would otherwise be very hard to achieve.
Using ESO’s Very Large Telescope (VLT) and the Atacama Large Millimetre/submillimetre Array (ALMA), the researchers studied the motion of gas within PJ0116-24.
“ALMA traces cold gas, seen here in blue, whereas the VLT, with its new Enhanced Resolution Imager and Spectrograph (ERIS), traces warm gas, shown in red,” they said.
“Thanks to these detailed observations, we discovered that the gas in this extreme galaxy was rotating in an organized fashion, rather than in the chaotic way expected after a galactic collision — a surprising result!”
“This shows convincingly that mergers aren’t always needed for a galaxy to become a HyLIRG.”
The team’s paper was published in the journal Nature Astronomy.
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D. Liu et al. Detailed study of a rare hyperluminous rotating disk in an Einstein ring 10 billion years ago. Nat Astron, published online July 15, 2024; doi: 10.1038/s41550-024-02296-7
Source : Breaking Science News