Astronomers may have found Milky Way's faintest satellite galaxy

Using a 8.2-meter telescope on the summit of Mauna Kea in Hawaii, an international team of researchers has found what could be the faintest dwarf satellite galaxy of our Milky Way.

Called Virgo I, the new dwarf satellite galaxy lies in the direction of the constellation Virgo at a distance of 280,000 light years from our Sun.

It has an absolute luminosity of -0.8 in the optical waveband, and such a remote galaxy with faint brightness has not been identified in previous sky surveys.

Its discovery suggested the presence of a large number of yet-undetected dwarf satellites in the halo of the Milky Way, according to the study published this week in The Astrophysical Journal.

"This discovery implies hundreds of faint dwarf satellites waiting to be discovered in the halo of the Milky Way," study leader Masashi Chiba, a professor from the Tohoku University in Japan, said in a statement.

"How many satellites are indeed there and what properties they have, will give us an important clue of understanding how the Milky Way formed and how dark matter contributed to it."

So far, some 50 satellite galaxies to the Milky Way have been identified.

Previously, the faintest dwarf satellites identified were Segue I (-1.5 absolute luminosity) and Cetus II (0.0 absolute luminosity), which were discovered through the Sloan Digital Sky Survey and the Dark Energy Survey, respectively. Endit