The phrase "home galaxy" refers to the galaxy where a person or thing belongs or originates from. It is like saying the galaxy where a person feels most familiar or comfortable, just like someone's home. Full definition
At the eyepiece of its own telescope, the intelligent extraterrestrial might likewise be ogling Disney's smaller, fainter home galaxy, the Milky Way. (discovermagazine.com)
«This particular FRB is the first detected to date to contain detailed information about the cosmic web — regarded as the fabric of the Universe — but it is also unique because its travel path can be reconstructed to a precise line of sight and back to an area of space about a billion light years away that contains only a small number of possible home galaxies.» (icrar.org)
Its home galaxy, which has yielded unique pairings previously, is sure to keep her busy. (sciencedaily.com)