Astronomers who are operating the Green Bank Telescope of the National Science Foundation in West Virginia have discovered that the dwarf galaxies surrounding our Milky Way Galaxy do not contain any of the gases required for the formation of stars. The scientists say it is actually the Milky Way that is sucking out important gases from dwarf galaxies.
Data collected from the Green Bank Telescope and other large radio telescopes led to new radio observations: within a specific boundary surrounding the Milky Way, the dwarf spheroidal galaxies in the area do not contain hydrogen. Beyond the boundary, the dwarf galaxies are found to be abundant in hydrogen.
Our Milky Way Galaxy is the biggest among a compact group of galaxies that are grouped together due to the pull of gravity. Surrounding the Milky Way are several dwarf galaxies, with the smallest ones being the dwarf spheroidal galaxies that are thought to be leftovers from the formation of galaxies. There are also other small but irregularly shaped dwarf galaxies further out that are not bound by the gravitational pull of the Milky Way. These galaxies are believed to be newer members of space.
The irregular dwarf galaxies that are further out from the Milky Way are known to contain huge amounts of the neutral hydrogen gas, which serves as the basis for the formation of stars.
The new research using the GBT, which is the biggest fully steerable radio telescope in the world, and other massive telescopes showed the previously unconfirmed theory that nearby dwarf galaxies within a certain boundary do not contain the star-forming hydrogen.
"What we found is that there is a clear break, a point near our home Galaxy where dwarf galaxies are completely devoid of any traces of neutral atomic hydrogen," said Kristine Spekkens, lead author of the study and an assistant professor in the Royal Military College of Canada.
The boundary in question is about 1,000 light years away from the Milky Way, and all the dwarf galaxies within it are affected by the enormous pull of the Milky Way and the halo of hydrogen plasma where the galaxy is located.
The scientists working on the study think that the density of the halo of the Milky Way is high enough to influence the composition of the neighboring dwarf galaxies, also revealing the size of the galaxy's halo.
Details of the research is published in the Astrophysical Journal Letters.
