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Discovery of an extended, halo-like stellar population around the Large Magellanic Cloud

Published online by Cambridge University Press:  01 July 2008

Steven R. Majewski
Affiliation:
Department of Astronomy, University of Virginia, Charlottesville, VA, 22904-4325, USA email: srm4n@virginia.edu, dnidever@virginia.edu, rrm8f@virginia.edu, rjp0i@virginia.edu, jc4qn@virginia.edu
David L. Nidever
Affiliation:
Department of Astronomy, University of Virginia, Charlottesville, VA, 22904-4325, USA email: srm4n@virginia.edu, dnidever@virginia.edu, rrm8f@virginia.edu, rjp0i@virginia.edu, jc4qn@virginia.edu
Ricardo R. Muñoz
Affiliation:
Department of Astronomy, University of Virginia, Charlottesville, VA, 22904-4325, USA email: srm4n@virginia.edu, dnidever@virginia.edu, rrm8f@virginia.edu, rjp0i@virginia.edu, jc4qn@virginia.edu
Richard J. Patterson
Affiliation:
Department of Astronomy, University of Virginia, Charlottesville, VA, 22904-4325, USA email: srm4n@virginia.edu, dnidever@virginia.edu, rrm8f@virginia.edu, rjp0i@virginia.edu, jc4qn@virginia.edu
William E. Kunkel
Affiliation:
Las Campanas Observatory, Carnegie Institution of Washington, Casilla 601, La Serena, Chile email: kunkel@lco.cl
Jeffrey L. Carlin
Affiliation:
Department of Astronomy, University of Virginia, Charlottesville, VA, 22904-4325, USA email: srm4n@virginia.edu, dnidever@virginia.edu, rrm8f@virginia.edu, rjp0i@virginia.edu, jc4qn@virginia.edu
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Abstract

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We describe an ongoing, large-scale, photometric and spectroscopic survey of the Large Magellanic Cloud (LMC) periphery. This survey uses Washington M, T2 + DDO51 photometry to identify distant LMC red giant branch (RGB) star candidates; multi-object spectroscopy is used to confirm the stellar surface gravities of these RGB stars and their association with the LMC (e.g., through radial velocities). The survey now encompasses hundreds of fields ranging from the LMC center with full azimuthal coverage around the LMC and out to 23° from the LMC center. We have confirmed the existence of RGB stars with (the unusual) Magellanic velocities out to the radial limit of this survey coverage. From data in a subsample of these fields, we show that this extended population of stars makes up a diffuse structure enveloping the LMC with a two-dimensional distribution resembling a classical halo with a shallow de Vaucouleurs profile and a broad metallicity spread around a typical mean value of [Fe/H] ~ −1.0.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2009

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