A Newly Discovered 'Einstein's Cross' Reveals the Existence of a Giant Dark Matter Halo

"The gravitational lensing not only splits the light source, but magnifies it, allowing a detailed view of the light source behind the lens. Thanks to this, the team says that HerS-3 appears to be a bright starburst galaxy-a galaxy undergoing explosive star formation-and was formed at a time when star formation was at its peak throughout the universe. HerS-3 also has a tilted, rotating disk, from the center of which gas is gushing out at a furious rate, the team say."

""Thanks to this natural telescope, we can zoom into regions 10 times smaller than the Milky Way, almost 12 billion light-years away, and in the process infer hidden matter in the light-of-sight," said Hugo Mesias, a coauthor of the paper, in a statement. At first glance, the Einstein's cross of HerS-3 appears to have been created solely by gravitational lensing generated by the four giant galaxies located between HerS-3 and Earth. "The only way to reproduce the remarkable configuration we observed was to add an invisible, massive component: a dark matter halo at the center of the galaxy group," said lead author Pierre Cox, from the Institut d'Astrophysique de Paris."

Gravitational lensing splits and magnifies background light, enabling detailed observation of distant sources. HerS-3 is a bright starburst galaxy formed near the peak epoch of cosmic star formation roughly 12 billion light-years away. Lens magnification allows zooming into regions ten times smaller than the Milky Way, revealing a tilted, rotating disk with intense central gas outflows. The visible mass of four foreground giant galaxies is insufficient to produce the observed five-image Einstein cross. Precise lens modeling requires an additional massive, invisible component. A dark matter halo at the center of the foreground galaxy group provides the necessary mass to reproduce the lensing configuration.

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