The baryon halo of the milky way: A fossil record of its formation
Astronomers believe that the baryon (stellar) halo of the Milky Way retains a fossil imprint of how it was formed. But a vast literature shows that the struggle to interpret the observations within a consistent framework continues. The evidence indicates that the halo has built up through a process of accretion and merging over billions of years, which is still going on at a low level. Future satellite missions to derive three-dimensional space motions and heavy element (metal) abundances for a billion stars will disentangle the existing web and elucidate how galaxies like our own came into existence.
Bland-Hawthorn
J
Anglo-Australian Observatory, PO Box 296, Epping, NSW 2121, Australia. Mount Stromlo and Siding Spring Observatories, Private Bag, Weston Creek ACT 2611, Australia.
Freeman
K