Astronomers using the Anglo-Australian telescope in outback Australia announced on Thursday the discovery of more than 40 previously unknown "dwarf" galaxies in a constellation "on Earth's doorstep".
The team of 12 scientists from five countries found the objects, so small they looked like stars, hidden in the nearby Fornax cluster of galaxies, they said in a statement issued in Sydney.
The Fornax cluster is 60 million light-years away, "in astronomical terms, on Earth's doorstep", they said.
Michael Drinkwater, the team leader from the University of Queensland, said the galaxies belonged to a class dubbed "ultra-compact dwarfs" (UCD).
UCDs were unknown until the same team using the Anglo-Australian telescope in north-western New South Wales state discovered six of them in the Fornax cluster in 2000.
The new discovery was formally announced Thursday at a meeting of the Royal Astronomical Society in Britain.
Drinkwater said researchers now believe the dwarf galaxies outnumber conventional elliptical and spiral galaxies in the central region of the Fornax cluster. Eight UCDs have also been found in the Virgo galaxy cluster, he said.
"It's likely that at least some are left-over examples of the primordial
building blocks that formed large galaxies by merging together," he said.
The scientists believe the UCDs are the nuclei of galaxies that were originally larger but have been stripped of their outer stars.
"It could be that they are very common, but scientists have overlooked them because they resemble nearby stars at first sight," he said.