NOAO >   Observing Info >   Approved Programs >   2012A-0148

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Proposal Information for 2012A-0148


PI: Ross Fadely, Haverford College, rossfadely@gmail.com
Address: Astronomy Department, 370 Lancaster Ave., Haverford, PA 19102, USA

CoI: Beth Willman, Haverford College
CoI: Marla Geha, Yale University

Title: Searching for Our Faintest Neighbors: Deep Imaging of Candidate Milky Way Dwarf Galaxy Satellites

Abstract: The census of faint galaxy satellites around the Milky Way is far from complete. We have systematically searched the RCS2 imaging survey and identified candidates for ultra-faint Milky Way galaxies at larger distances than previously explored. The RCS2 survey covers 750 sq degrees to a limiting magnitude of r~24, two magnitudes below the Sloan Digital Sky Survey in which all the known ultra-faint galaxies have so far been detected. We identify two promising ultra-faint candidates which appear to lie between 400 kpc < d < 800 kpc based on the presence of red giant branch (RGB) stars. We propose Gemini-N GMOS and NIRI imaging in g, r, and J to confirm each candidate by revealing its stellar sequence down the RGB. Two optical and one near- infrared filters are required to distinguish a low-surface brightness stellar population from the sea of unresolved galaxies at faint magnitudes. If confirmed, these will be the first Milky Way ultra-faint galaxies discovered outside of SDSS data, and will be the most distant of these low luminosity systems. If ruled out, these observations will inform our ongoing and future searches of deep, wide-field data for Milky Way satellites.


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NOAO >   Observing Info >   Approved Programs >   2012A-0148

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