The Milky Way belongs to a bigger group of galaxies known as the Laniakea Galactic Supercluster but if this cosmic structure is compared to a group of kids, the Milky Way is one big bully that steals from its smaller and weaker peers.
Our home galaxy is among the largest members of the Laniakea Galactic Supercluster, where it is surrounded by a cluster of smaller dwarf galaxies with the smallest being the relatively near dwarf spheroidals that astronomers believe to be leftover crumbs from the formation of the Milky Way.
Based on observations made by the Green Bank Telescope (GBT) of the National Science foundation and other data from other radio telescopes, astronomers discovered that these dwarf spheroidal galaxies that surround the Milky Way are devoid of hydrogen, a star-forming gas, and it appears that our galaxy is to blame.
The researchers discovered that there is a point near the Milky Way that our small galactic neighbors do not have traces of the star-forming neutral atomic hydrogen, and this has stunted their growth. There appears to be a danger zone where the neutral hydrogen gas from the dwarf spheroids are stripped as they orbit the Milky Way at speed of over a million miles per hours, which helps explain why dwarf spheroid galaxies are rare within a distance of 1,000 light-years from the outer edge of the Milky Way but abound beyond this boundary.
"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, an astronomer from the Royal Military College of Canada and lead researcher of the study that detailed the findings.
"The Dearth of Neutral Hydrogen in Galactic Dwarf Spheroidal Galaxies," was published in the Astrophysical Journal Letters on Oct. 13.
The Milky Way sits within an extended halo of hot hydrogen plasma. Scientists believe that the halo's density is enough to affect the composition of the small galaxies. The pressure produced by the orbital velocities of the dwarf spheroidal galaxies can strip away the detectable traces of hydrogen gas, this indicate that the Milky Way is to blame for shutting down the star-forming abilities of its smaller galactic neighbors.
"These observations therefore reveal a great deal about size of the hot halo and about how companions orbit the Milky Way," Spekkens said.
