Washington: Scientists have identified nine new dwarf galaxies, which is the largest number ever found at once, in orbit around the Milky Way.
The findings by a team of astronomers from the University of Cambridge , newly-released imaging data taken from the Dark Energy Survey, may help unravel the mysteries behind dark matter, the invisible substance holding galaxies together.
The new satellites were found in the southern hemisphere near the Large and Small Magellanic Cloud, the largest and most well-known dwarf galaxies in the Milky Way's orbit.
The newly discovered objects are a billion times dimmer than the Milky Way, and a million times less massive. The closest is about 95,000 light-years away, while the most distant is more than a million light-years away.
Scientists have said that 3 of the discovered objects were definite dwarf galaxies, while others could be either dwarf galaxies or globular clusters-objects with similar visible properties to dwarf galaxies, but not held together with dark matter.
Study's lead author Dr. Sergey Koposov said that the discovery of so many satellites in such a small area of the sky was completely unexpected, and he couldn't believe his eyes.
Dwarf galaxies are the smallest galaxy structures observed, the faintest of which contain just 5,000 stars-the Milky Way, in contrast, contains hundreds of billions of stars. Standard cosmological models of the universe predict the existence of hundreds of dwarf galaxies in orbit around the Milky Way, but their dimness and small size makes them incredibly difficult to find, even in our own 'backyard.'
The Dark Energy Survey is a five-year effort to photograph a large portion of the southern sky in unprecedented detail. Its primary tool is the Dark Energy Camera, which at 570 megapixels is the most powerful digital camera in the world, able to see galaxies up to eight billion light-years from Earth. Built and tested at Fermilab, the camera is now mounted on the four-meter Victor M. Blanco telescope at the Cerro Tololo Inter-American Observatory in the Andes Mountains in Chile. The camera includes five precisely shaped lenses, the largest nearly a yard across, designed and fabricated at University College London (UCL) and funded by the UK Science and Technology Facilities Council (STFC).
The research is due to be published in The Astrophysical Journal.