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Title: A ''LIGHT'', CENTRALLY CONCENTRATED MILKY WAY HALO?

We discuss a novel approach to ''weighing'' the Milky Way (MW) dark matter halo, one that combines the latest samples of halo stars selected from the Sloan Digital Sky Survey (SDSS) with state of the art numerical simulations of MW analogs. The fully cosmological runs employed in the present study include ''Eris'', one of the highest resolution hydrodynamical simulations of the formation of a M{sub vir} = 8 Multiplication-Sign 10{sup 11} M{sub Sun} late-type spiral, and the dark-matter-only M{sub vir} = 1.7 Multiplication-Sign 10{sup 12} M{sub Sun} ''Via Lactea II'' (VLII) simulation. Eris provides an excellent laboratory for creating mock SDSS samples of tracer halo stars, and we successfully compare their density, velocity anisotropy, and radial velocity dispersion profiles with the observational data. Most mock SDSS realizations show the same ''cold veil'' recently observed in the distant stellar halo of the MW, with tracers as cold as {sigma}{sub los} Almost-Equal-To 50 km s{sup -1} between 100 and 150 kpc. Controlled experiments based on the integration of the spherical Jeans equation as well as a particle tagging technique applied to VLII show that a ''heavy'' M{sub vir} Almost-Equal-To 2 Multiplication-Sign 10{sup 12} M{sub Sun} realistic host produces a poor fit tomore » the kinematic SDSS data. We argue that these results offer added evidence for a ''light'', centrally concentrated MW halo.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4]
  1. Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
  2. Department of Astronomy and Astrophysics, UCO/Lock Observatory, University of California, Santa Cruz, CA 95064 (United States)
  3. Institute for Astronomy, ETH Zurich, 8093 Zurich (Switzerland)
  4. Institute of Theoretical Physics, University of Zurich, CH-9057 Zurich (Switzerland)
Publication Date:
OSTI Identifier:
22136572
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 773; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; COMPUTERIZED SIMULATION; HYDRODYNAMIC MODEL; MILKY WAY; MONITORING; NONLUMINOUS MATTER; RADIAL VELOCITY; RESOLUTION; SKY; SPHERICAL CONFIGURATION; STARS