A new map of twelve streams of stars orbiting within our galactic halo has lead astronomers one step closer to reveal the properties of dark matter enveloping our Milky Way galaxy.
Astronomers wants to understand these star streams. Dark matter that holds the stars in their orbits also tell us about the formation history of the Milky Way. It reveals that Milky Way has steadily grown over billions of years by consuming smaller stellar systems.
Scientists have initiated a programme named the Southern Stellar Stream Spectroscopic Survey (S5) in order to measure the properties of stellar streams. These properties include the shredded remains of neighbouring small galaxies.
This is the first-time scientists studied such a rich collection of stellar streams. They have used the Anglo-Australian Telescope which is a 4-meter optical telescope in Australia. They have also used the Doppler shift of light in order to find out how fast individual stars are moving.
In the new study, they have focused on one stream at a time. Scientists said, the properties of stellar streams reveal the presence of the invisible dark matter of the Milky Way.
Scientists have also used their observations to work out the chemical compositions of the stars. This is how they told us where they were born.
Scientists think, these new observations are important to determine how our Milky Way arose from the featureless universe after the Big Bang.
Scientists also said that, a crucial ingredient for the success of S5 were observations from the European Gaia space mission.
Scientists are also thinking about producing more measurements on stellar streams in the Milky Way. But scientists are happy with the results as a starting point.
The study has been published in the American Astronomical Society’s Astrophysical Journal.