NOAO >   Observing Info >   Approved Programs >   2004A-0462

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Proposal Information for 2004A-0462


PI: Steven R. Majewski, University of Virginia, srm4n@virginia.edu
Address: Astronomy Department, P.O. Box 3818, Charlottesville, VA 22936-0818, USA

CoI: \v Zeljko Ivezic, Princeton University
CoI: Richard J. Patterson, University of Virginia
CoI: Helio J. Rocha-Pinto, University of Virginia
CoI: Michael F. Skrutskie, University of Virginia
CoI: Martin Weinberg, University of Massachusetts
CoI: Jeffrey Crane, University of Virginia
CoI: Francisco Prada, Instituto de Astrofisica de Andalucia

Title: New Tidal Stream Candidates in the Outer Milky Way

Abstract: \vskip -0.2in 2MASS and SDSS have proven extremely useful databases for finding and tracing halo substructure within 50 kpc. However, we have found very close agreement between the distributions of 2MASS M giants and SDSS RR Lyraes \it beyond 50 kpc in three regions explored by the SDSS, including several significant overdensities of stars that are likely new tidal stream structures. The SDSS-2MASS correspondence in these small SDSS test probes lends great confidence that the 2MASS database can be trusted to at least 100 kpc, opening new volumes of the outer halo where 2MASS studies hint at other large tidal features like the Sgr arms recently mapped with 2MASS M giants by Majewski et al. (2003a). We request Mayall 4-m + RCspec time to verify with radial velocities the reality of these new candidate tidal features and provide strong constraints on the orbit and mass of tidal debris progenitors. The 2MASS M giant database has already placed new constraints on the Galactic potential (e.g., Majewski et al. 2003b, Law et al. 2003a,b); if traced over sufficient length, well-populated, Sgr-like tidal streams in the outer halo will place even stronger constraints on the shape and total mass of the Milky Way and its dark halo.


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