The Milky Way is believed to be stripping away the star-forming gas of nearby dwarf galaxies.
Data from the National Science Foundation's Green Bank Telescope(GBT) suggests nearby dwarf galaxies are completely devoid of hydrogen gas, and our own galaxy is to blame, the National Radio Astronomy Observatory reported. Galaxies further away from the hungry Milky Way have been proven to be rich in this type of gas.
"Astronomers wondered if, after billions of years of interaction, the nearby dwarf spheroidal galaxies have all the same star-forming 'stuff' that we find in more distant dwarf galaxies," said astronomer Kristine Spekkens, assistant professor at the Royal Military College of Canada and lead author on the paper published in a recent edition of the journal Astrophysical Journal Letters.
Past studies have shown dwarf irregular galaxies across the universe tend to be teeming with neutral hydrogen gas, which spurs star formation. Using the large radio telescope and other equipment from around the world the researchers were finally able to determine that those close to our own galaxy are mysteriously dry of this lifeblood gas.
"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," Spekkens said.
Beyond this point (the border of which is about 1,000 light-years away) there is are very few of these dwarf spheroidals and a good amount of gas-rich dwarf galaxies.
Gas can be lost from galaxies through processes such as jets of material from supermassive black holes and powerful star formation, but the dwarf neighbors of the Milky Way contain neither of these. The researchers believe orbiting dwarf spheroidals near the Milky Way's star-filled disk achieve such a high pressure that gas is stripped away, shutting down star formation.
"These observations therefore reveal a great deal about size of the hot halo and about how companions orbit the Milky Way," Spekkens said.
