An Investigation of the Canis Major Overdensity

ORAL

Abstract

Using 2MASS colors Martin et al. (2004) uncovered evidence for a remnant dwarf galaxy in Canis Major, in the form of an overdensity of M-giant stars. The spatial distribution of the M-giants indicate an extended, and likely disrupted, group of stars extending over roughly 30 degrees of the sky. The nature of this overdensity would have ramifications to our understanding of our Galaxy's thick disk population and its formation history. We made a photometric survey to find candidate horizontal branch stars that match the characteristics of the Canis Major overdensity. The goal was to find a group of horizontal branch stars, as is expected for an old population, in the Canis Major dwarf. We performed spectroscopy on a group of these candidate stars. We present new photometry and color magnitude diagrams for various Canis fields and include kinematic results.

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Authors

  • W.L. Powell Jr.

  • Ronald Wilhelm

  • Nilanjan Das

    Dept. of Physics, ESFM-IPN, Mexico City, Dept. of Physics, The University of Texas at El Paso, Texas A\&M University, Southeast Missouri State University, Departamento de Fisica, FCEN, Universidad de Buenos Aires, Nunez, Argentina, Cyclotron Institute, Texas A\&M University, University of Houston, Denison U., Advanced Space Propulsion Laboratory, AdAstra Rocket Company, Texas Tech University, Department of Chemistry and Biochemistry, Texas State Unv. - San Marcos, Department of Physics, Texas State Unv. - San Marcos, Rice U., Texas State University - San Marcos, Freescale Semiconductor, Inc., Varian Semiconductor Equipment Associates, Gloucester, MA, University of North Texas, Denton, TX, National Insitute of Standards \& Technology, Gaithersburg, MD, James Madison University, Harrisonburg, VA, Texas A\&M University, College Station, TX, Hong Kong University of Science and Technology; Texas Center for Superconductivity and Advanced Materials, University of Houston, Texas Center for Superconductivity at the University of Houston, University of Houston, University of Idaho, Department of Physics, Istanbul Technical University, University of California at Davis, Physics Department, University of South Florida, FL 33620, Physics Department, Texas A\&M University, TX 77843, Center for Studies in Statistical Mechanics and Complex Systems, The University of Texas at Austin, Rice University, TcSUH, University of Houston, Lawrence Berkeley National Laboratory, Hong Kong University of Science and Technology, Institute of Solid State Physics, Bulgarian Academy of Sciences, Hong Kong University of Science and Technology; Texas Center for Superconductivity, University of Houston; Lawrence Berkeley National Laboratory, Texas Center for Superconductivity, University of Houston

  • Nilanjan Das

    Dept. of Physics, ESFM-IPN, Mexico City, Dept. of Physics, The University of Texas at El Paso, Texas A\&M University, Southeast Missouri State University, Departamento de Fisica, FCEN, Universidad de Buenos Aires, Nunez, Argentina, Cyclotron Institute, Texas A\&M University, University of Houston, Denison U., Advanced Space Propulsion Laboratory, AdAstra Rocket Company, Texas Tech University, Department of Chemistry and Biochemistry, Texas State Unv. - San Marcos, Department of Physics, Texas State Unv. - San Marcos, Rice U., Texas State University - San Marcos, Freescale Semiconductor, Inc., Varian Semiconductor Equipment Associates, Gloucester, MA, University of North Texas, Denton, TX, National Insitute of Standards \& Technology, Gaithersburg, MD, James Madison University, Harrisonburg, VA, Texas A\&M University, College Station, TX, Hong Kong University of Science and Technology; Texas Center for Superconductivity and Advanced Materials, University of Houston, Texas Center for Superconductivity at the University of Houston, University of Houston, University of Idaho, Department of Physics, Istanbul Technical University, University of California at Davis, Physics Department, University of South Florida, FL 33620, Physics Department, Texas A\&M University, TX 77843, Center for Studies in Statistical Mechanics and Complex Systems, The University of Texas at Austin, Rice University, TcSUH, University of Houston, Lawrence Berkeley National Laboratory, Hong Kong University of Science and Technology, Institute of Solid State Physics, Bulgarian Academy of Sciences, Hong Kong University of Science and Technology; Texas Center for Superconductivity, University of Houston; Lawrence Berkeley National Laboratory, Texas Center for Superconductivity, University of Houston

  • Nilanjan Das

    Dept. of Physics, ESFM-IPN, Mexico City, Dept. of Physics, The University of Texas at El Paso, Texas A\&M University, Southeast Missouri State University, Departamento de Fisica, FCEN, Universidad de Buenos Aires, Nunez, Argentina, Cyclotron Institute, Texas A\&M University, University of Houston, Denison U., Advanced Space Propulsion Laboratory, AdAstra Rocket Company, Texas Tech University, Department of Chemistry and Biochemistry, Texas State Unv. - San Marcos, Department of Physics, Texas State Unv. - San Marcos, Rice U., Texas State University - San Marcos, Freescale Semiconductor, Inc., Varian Semiconductor Equipment Associates, Gloucester, MA, University of North Texas, Denton, TX, National Insitute of Standards \& Technology, Gaithersburg, MD, James Madison University, Harrisonburg, VA, Texas A\&M University, College Station, TX, Hong Kong University of Science and Technology; Texas Center for Superconductivity and Advanced Materials, University of Houston, Texas Center for Superconductivity at the University of Houston, University of Houston, University of Idaho, Department of Physics, Istanbul Technical University, University of California at Davis, Physics Department, University of South Florida, FL 33620, Physics Department, Texas A\&M University, TX 77843, Center for Studies in Statistical Mechanics and Complex Systems, The University of Texas at Austin, Rice University, TcSUH, University of Houston, Lawrence Berkeley National Laboratory, Hong Kong University of Science and Technology, Institute of Solid State Physics, Bulgarian Academy of Sciences, Hong Kong University of Science and Technology; Texas Center for Superconductivity, University of Houston; Lawrence Berkeley National Laboratory, Texas Center for Superconductivity, University of Houston