SPACE.COM - A fresh analysis of a remarkably massive yet compact galaxy from the early universe suggests that dark matter interacts with itself.
The galaxy, JWST-ER1, which formed just 3.4 billion years after the Big Bang, was first spotted last October in images snapped by NASA's James Webb Space Telescope (JWST). At over 17 billion light-years from Earth, JWST-ER1g is the farthest-ever example of a perfect "Einstein ring" — an unbroken circle of light around the galaxy, a result of light rays from a distant, unseen galaxy being bent due to the space-warping mass of JWST-ER1.
"The value for the dark matter mass seems higher than expected," Hai-Bo Yu, a professor of physics and astronomy at the University of California, Riverside (UCR) and a co-author of the new study, said in a statement. "This is puzzling."
In a new paper, Yu and his colleagues suggest that JWST-ER1g's unusually high density could be explained by a higher population of stars than currently thought. However, a contraction mechanism by which ordinary matter — the stuff that makes up gas and stars — "collapses and condenses" into JWST-ER1g's dark matter halo could be packing "more dark matter mass in the same volume, resulting in higher density," study lead author Demao Kong of UCR said in the same statement.