Lyman-$\alpha$ Forest Constraints on Decaying Dark Matter and Implications for Galactic Substructure Properties

ORAL

Abstract

I present an analysis of high-resolution N-body simulations of decaying dark matter (DDM) cosmologies which focuses on the statistical properties of the transmitted Lyman-$\alpha$ (Ly$\alpha$) flux in the high-redshift intergalactic medium (IGM). In this type of model, a dark matter particle decays into a slightly less massive stable dark matter particle and a massless particle. The small mass splitting will provide a non-relativistic kick velocity $V_k$ to the daughter particle and result in free-streaming effect. I especially focus on late decay scenario with decay lifetime around the order of the age of the Universe. I present new limits on unstable dark matter models using current Ly$\alpha$ forest data sets combined with the WMAP7 data. I also use zoom-in numerical simulations to explore the ability of DDM models to solve the small scale problem in galactic halos. I have found that these particular DDM models may provide a solution to both the Galactic subhalo abundance and core/cusp problems, and also that they are consistent with current Ly$\alpha$ limits.

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Authors

  • Mei-Yu Wang

    Indiana Univ - Bloomington

  • John Royston

    Ball State University, Naval Research Laboratory, Washington, DC 20375, USA, Univ of Cincinnati, KITP China, U.C. Berkeley, FNAL, Cornell, West Virginia University, University of Pittsburgh, The Ohio State University, Carnegie Mellon University, Miami University, University of Notre Dame, University of Nebraska-Lincoln, Miami Univ, Australia National Univ., Miami Univ., Univ. of Cincinnati, Physics and Astronomy Department, Ohio University, Athens, OH 45701, Australian National University, University of Toledo, The University of Toledo, University of Toledo, Wright Center for Photovoltaics Innovation and Commercialization, University of Cincinnati, University of California, Davis

  • John Royston

    Ball State University, Naval Research Laboratory, Washington, DC 20375, USA, Univ of Cincinnati, KITP China, U.C. Berkeley, FNAL, Cornell, West Virginia University, University of Pittsburgh, The Ohio State University, Carnegie Mellon University, Miami University, University of Notre Dame, University of Nebraska-Lincoln, Miami Univ, Australia National Univ., Miami Univ., Univ. of Cincinnati, Physics and Astronomy Department, Ohio University, Athens, OH 45701, Australian National University, University of Toledo, The University of Toledo, University of Toledo, Wright Center for Photovoltaics Innovation and Commercialization, University of Cincinnati, University of California, Davis

  • John Royston

    Ball State University, Naval Research Laboratory, Washington, DC 20375, USA, Univ of Cincinnati, KITP China, U.C. Berkeley, FNAL, Cornell, West Virginia University, University of Pittsburgh, The Ohio State University, Carnegie Mellon University, Miami University, University of Notre Dame, University of Nebraska-Lincoln, Miami Univ, Australia National Univ., Miami Univ., Univ. of Cincinnati, Physics and Astronomy Department, Ohio University, Athens, OH 45701, Australian National University, University of Toledo, The University of Toledo, University of Toledo, Wright Center for Photovoltaics Innovation and Commercialization, University of Cincinnati, University of California, Davis

  • John Royston

    Ball State University, Naval Research Laboratory, Washington, DC 20375, USA, Univ of Cincinnati, KITP China, U.C. Berkeley, FNAL, Cornell, West Virginia University, University of Pittsburgh, The Ohio State University, Carnegie Mellon University, Miami University, University of Notre Dame, University of Nebraska-Lincoln, Miami Univ, Australia National Univ., Miami Univ., Univ. of Cincinnati, Physics and Astronomy Department, Ohio University, Athens, OH 45701, Australian National University, University of Toledo, The University of Toledo, University of Toledo, Wright Center for Photovoltaics Innovation and Commercialization, University of Cincinnati, University of California, Davis