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Title: Milky Way mass and potential recovery using tidal streams in a realistic halo

We present a new method for determining the Galactic gravitational potential based on forward modeling of tidal stellar streams. We use this method to test the performance of smooth and static analytic potentials in representing realistic dark matter halos, which have substructure and are continually evolving by accretion. Our FAST-FORWARD method uses a Markov Chain Monte Carlo algorithm to compare, in six-dimensional phase space, an 'observed' stream to models created in trial analytic potentials. We analyze a large sample of streams that evolved in the Via Lactea II (VL2) simulation, which represents a realistic Galactic halo potential. The recovered potential parameters are in agreement with the best fit to the global, present-day VL2 potential. However, merely assuming an analytic potential limits the dark matter halo mass measurement to an accuracy of 5%-20%, depending on the choice of analytic parameterization. Collectively, the mass estimates using streams from our sample reach this fundamental limit, but individually they can be highly biased. Individual streams can both under- and overestimate the mass, and the bias is progressively worse for those with smaller perigalacticons, motivating the search for tidal streams at galactocentric distances larger than 70 kpc. We estimate that the assumption of a staticmore » and smooth dark matter potential in modeling of the GD-1- and Pal5-like streams introduces an error of up to 50% in the Milky Way mass estimates.« less
Authors:
;  [1] ; ;  [2] ;  [3] ;  [4]
  1. Department of Astronomy, Yale University, New Haven, CT 06511 (United States)
  2. Department of Astronomy, Columbia University, New York, NY 027 (United States)
  3. Institute for Computational Sciences, University of Zürich, 8057 Zurich (Switzerland)
  4. Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place # 424, New York, NY 10003 (United States)
Publication Date:
OSTI Identifier:
22370278
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; ALGORITHMS; COMPARATIVE EVALUATIONS; DISTANCE; GALAXIES; GRAVITATION; MARKOV PROCESS; MASS; MILKY WAY; MONTE CARLO METHOD; NONLUMINOUS MATTER; PHASE SPACE; SIMULATION; STELLAR WINDS; STREAMS