Using the Subaru Telescope located in Japan, astronomers have made another unprecedented discovery as they spotted that something is actually orbiting our galaxy.
Astronomers believe it is the ‘faintest’ companion ever found. The galaxy called Virgo 1, connects around 50 known companions to our galaxy.
It is located around 280,000-light-years away from Earth and is a miniature 124 light-years in diameters—which according to reports is even small for a dwarf galaxy. Compared to Virgo 1, the Milky way is around 100,000-light-years in diameter.
“We have identified a new ultra-faint dwarf satellite of the Milky Way, Virgo I, in the constellation of Virgo,” the astronomers said.
“The satellite is located at a heliocentric distance of 284,000 light-years and its absolute magnitude in the V band is estimated as -0.8 mag, which is comparable to or fainter than that of the faintest dwarf satellite, Segue 1.”
“The half-light radius of Virgo I is estimated to be 124 light-years, significantly larger than globular clusters with the same luminosity, suggesting that it is a dwarf galaxy.”
The newly found companion of the Milky Way wasn’t found in previous surveys since it was below the detection limit.
Location (left) and a density graph (right) of newly discovered galaxy Virgo I. Tohoku University/National Astronomical Observation of Japan
Observing the sky, astronomers state that Virgo 1 appears 1.5 BILLION times FAINTER than the Large Magellanic Cloud, which is the Milky Way’s largest companion. The newly found galaxy has an absolute magnitude of -0.8, making it 1.6 times fainter than our Sun.
“This discovery implies hundreds of faint dwarf satellites waiting to be discovered in the halo of the Milky Way,” senior author Masashi Chiba, from Tohoku University, 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.”
The discovery was part of the ongoing Hyper Suprime-Cam Subaru Strategic Program.
“We have carefully examined the early data of the Subaru Strategic Survey with Hyper Suprime Cam (a gigantic wide-field camera on NAOJ’s Subaru Telescope on Mauna Kea, Hawaii) and found an apparent over-density of stars in Virgo with very high statistical significance, showing a characteristic pattern of an ancient stellar system in the color-magnitude diagram,” said team member Daisuke Homma, a graduate student at Tohoku University in Japan.
“This discovery implies hundreds of faint dwarf satellites waiting to be discovered in the halo of the Milky Way,” said team member Dr. Masashi Chiba, also from Tohoku University.
“How many satellites are indeed there and what properties they have, will give us an important clue to understanding how the Milky Way formed and how dark matter contributed to it.”
Astronomers indicate that simulation of the cosmos indicate that there should be much more smaller galaxies than what we have observed so far, maybe the reason is that our instruments are only recently getting good enough and we may have overlooked a bunch of galaxies in the past.
Featured image by Archange1Michael