A recent paper reporting the first major results of the Pan-Andromeda Archaeological Survey provides a striking look at what can be learned from the relatively young field of galactic archaeology. 1 The PANDAS collaboration has undertaken what it calls a “panoramic survey” of the Andromeda galaxy and its extended environs, using a wide-field camera on the 3.6-m-diameter Canada-France-Hawaii Telescope (CFHT) atop Mauna Kea. The survey is archaeology in the sense that a principal goal is to find relics of past cannibalistic encounters between Andromeda and its satellite dwarf galaxies. Favored hierarchical theories of galaxy formation predict the existence of such relics.
At a distance of only 2.5 million light-years, Andromeda, a 1012-star spiral galaxy very much like the Milky Way, is our nearest full-grown galactic neighbor. As such, it presents a unique opportunity for a systematic search for remnants of galaxy formation unbiased by the inevitable limitations of...
