Astronomers have discovered a ghostly galaxy that appears to be devoid of dark matter, challenging our current understanding of the universe. The latest “ultradiffuse galaxy,” FCC 224, is about the size of the Milky Way but contains only about a dozen luminous stars. What’s more, it lacks the strong gravitational pull expected from dark matter.
Researchers led by Maria Buzzo and Yimeng Tang have tracked the movement of star clusters within FCC 224 using data from the Keck Observatory in Hawaii. The measurements revealed a slow speed among the clusters, indicating that the galaxy lacks dark matter. No existing galaxy formation model can currently explain how this galaxy came to be.
The team suggests two possible scenarios for FCC 224’s formation: it may have formed from a high-velocity collision of gas-rich galaxies, resulting in the separation of gas and dark matter, or it could be the result of a chaotic environment with intense star formation that expelled dark matter. Alternatively, there may be another galaxy that shares similar properties, such as FCC 240.
The discovery of this mysterious galaxy sheds light on our understanding of dwarf galaxy formation and the role of dark matter in the universe.
Source: https://www.space.com/the-universe/ghostly-galaxy-without-dark-matter-baffles-astronomers