https://phys.org/news/2018-11-small-galaxies-milky.html

These small galaxies have been the subject of the study of an international team of astronomers led by Tobias K. Fritz and Giuseppina Battaglia, both researchers of the Instituto de Astrofísica de Canarias (IAC). Thanks to the data acquired by the ESA Gaia space mission, which became available in a second release in April 2018, the researchers have been able to measure the on-sky motion of 39 dwarf galaxies, determining direction and velocity.

Before the second release of data from the Gaia satellite, it was not possible to perform such measurements for 29 of the galaxies analyzed by the team. The researchers found that many of them are moving in a plane known as the vast polar structure. "It was already known that many of the more massive dwarf galaxies were found in this plane, but now we know that also several of the less massive dwarf galaxies might belong to this structure," says Fritz, main author of the scientific article .