NOAO >   Observing Info >   Approved Programs >   2011B-0575

Small NOAO Logo

Proposal Information for 2011B-0575


PI: Steven Majewski, University of Virginia, srm4n@virginia.edu
Address: Dept. of Astronomy, P.O. Box 400325, Charlottesville, VA 22904-4325, USA

CoI: Kathryn Johnston, Columbia University
CoI: Helio Rocha-Pinto, UFRJ, Observatorio do Valongo, Brazil
CoI: Richard Patterson, University of Virginia
CoI: Allyson Sheffield, Columbia University
CoI: Guillermo Damke, University of Virginia
CoI: Jeffrey Carlin, Rensselaer Polytechnic Institute
CoI: Ricardo Munoz, Yale University, Universidad de Chile

Title: Testing Dynamical Models of Star Cloud Formation with the Tri-And System

Abstract: This proposal requests time to map the radial velocity structure of the Triangulum-Andromeda cloud --- one of several amorphous stellar structures discovered in recent years in the Galactic halo. Models suggest that, like the more well-known stellar streams, these clouds could result from the disruption of satellites during the hierarchical formation of our Galaxy. The models have definite predictions that differentiate clouds from streams in: velocity (they should exhibit strong velocity gradients), origin (their progenitor objects should be on highly eccentric orbits) and location (the clouds should lie at the orbital apocenter of the parent satellite). Perhaps the most intriguing property of clouds is that their debris is expected to have explored a large a range of radii, and hence should be sensitive to the radial profile of the Galactic dark matter distribution. However, none of these clouds in the Milky Way have yet been extensively mapped. Our program results will be used either to confirm or refute the origin of these structures as suggested by the models, to guide creation of a new model made specifically for the Triangulum-Andromeda system, and to serve as new constraints on the Galactic potential.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2011B-0575

noaoprop-help@noao.edu

Small NOAO Logo