Collaborative Research: Jump Starting LSST Proper Motion Science with 12 Years of DECam Observations

Precise measurements of the motions of stars on the celestial sphere are critical for understanding the formation and content of the Milky Way galaxy. Astronomers create computer models of the motions of stars to help understand assembly history of the Milky Way, the nature of dark matter, and look for planets around nearby stars. However, the motions of stars are extremely and difficult to measure. Moderately bright stars have been measured with exquisite precision by the European Space Agency’s Gaia spacecraft, but larger telescopes are required to measure fainter stars. The investigators will develop and apply new techniques to measure the motions of faint stars using some of the world’s most powerful ground-based survey telescopes. As part of this project, the investigators will provide scientific and technical training for graduate and undergraduate students. Furthermore, the investigators will engage and educate the general public with visualizations of the dynamic motion of stars in the Milky Way. The investigators will measure the astrometric positions of stars in hundreds of thousands of images collected by the Dark Energy Camera (DECam) on NSF’s 4-m Blanco Telescope. The investigators will use the DECam data to perform best-ever measurements of the proper motions of hundreds of millions of stars that are too faint to have been measured previously. The DECam data cover nearly the entire sky area of the Vera C. Rubin Observatory’s unprecedented Legacy Survey of Space and Time (LSST). The investigators will combine the DECam and LSST data to measure the positions and motions of stars much more precisely than would be possible with the first year of LSST alone. This research award is partially funded by a generous gift from Charles Simonyi to the NSF Astronomy division. The project includes significant contributions to Vera C. Rubin Observatory’s Legacy Survey of Space and Time. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.