Ghostly remnants of galaxy interactions uncovered in a nearby galaxy group

Astronomers have observed the nearby large spiral galaxy M81, together with its two brightest neighbors. The team obtained deep and super wide-field images of the galaxies and discovered that the spatial distribution of the young stars around these galaxies follows very closely that of their distribution of neutral hydrogen. This is the first endeavor beyond the Local Group of galaxies to demonstrate the hierarchical galaxy assembly process on galactic scales. —> Read More