NOAO >   Observing Info >   Approved Programs >   2014B-0047

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Proposal Information for 2014B-0047


PI: Thomas de Boer, Institute of Astronomy, University of Cambridge, tdeboer@ast.cam.ac.uk
Address: Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, United Kingdom

CoI: Vasily Belokurov, Institute of Astronomy, University of Cambridge
CoI: Sergey Koposov, Institute of Astronomy, University of Cambridge
CoI: Mike Irwin, Institute of Astronomy, University of Cambridge
CoI: Denis Erkal, Institute of Astronomy, University of Cambridge

Title: Charting the trajectory of the ATLAS stream

Abstract: Stellar streams provide dramatic confirmation that large systems accrete smaller systems, in the context of a hierarchical merging cosmology, and therefore contain important clues about the formation mechanism of the Galactic halo. By studying the detailed properties of streams we can determine how stars are stripped from their hosts due to the Galactic tidal field and how the formation of the Galactic halo may have proceeded. Here we propose to trace the full visible extent of the recently discovered ATLAS stream using deep, wide-field photometry, to determine its path across the sky in 3 dimensions. By utilising the very wide-field capabilities of DECam, we will determine the deep, MW decontaminated CMD in a 30 degree long portion of the stream, allowing us to determine the distance, density profile and stellar population makeup of the stream. The position and density on the sky of kinematically cold structures like the ATLAS stream provides powerful, unbiased constraints on the distribution of dark matter in the Galaxy. Furthermore, deep photometry of the stellar content of the stream will tell us what type of system was the likely progenitor: globular cluster, ultra-faint dwarf or dSph galaxy.


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NOAO >   Observing Info >   Approved Programs >   2014B-0047

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