The researchers will study our Milky Way galaxy and the great star clouds of Sagittarius, which are easily visible on a dark summer night, low on the Southern horizon, from the anywhere in the United States. Their observation plan is to precisely measure the colors of stars in the brightest part of the Milky Way, including the bulge of stars near the center of our galaxy. Their scientific target is understanding the origin and history of formation of stars in the bulge. The investigators will use the Dark Energy Camera (currently most powerful on any telescope) on the 4m telescope at the Cerro Tololo observatory in Chile. They will produce a sequence of color images, from infrared, optical to ultraviolet wavelengths. The broader impact of this program has several components. Foremost is providing professional astronomers and public with tools to view the multi-color images online. The investigators will give the public access to the same data as are used by professional astronomers. The investigators will report the results via popular journal articles, public lectures and sky viewing events.
The collaboration will use these detailed images of the bulge of our Milky Way to map the structure of its stars, deduce their age and metal content, to shed light on the structure and formation history of the bulge stars. An additional bonus will be detailed images of over 30 globular star clusters in the six filters observed by the collaboration. Over time, the space motions of stars will be measured, enabling study of the stellar orbits that support the structure of the bulge. The bulge of stars surrounding the core of our galaxy was likely formed as the result of three processes, 1) rapid, violent merging within the first billion years after the Big Bang, 2) ongoing mergers of massive stellar clusters and 3) formation from the early disk of the Milky Way, by slower dynamical processes.
The collaboration's images and derived measurements, combined with additional studies, have the potential to transform our understanding of the formation of the Galaxy.
