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Title: Using gaps in N-body tidal streams to probe missing satellites

We use N-body simulations to model the tidal disruption of a star cluster in a Milky-Way-sized dark matter halo, which results in a narrow stream comparable to (but slightly wider than) Pal-5 or GD-1. The mean Galactic dark matter halo is modeled by a spherical Navarro-Frenk-White potential with subhalos predicted by the ΛCDM cosmological model. The distribution and mass function of the subhalos follow the results from the Aquarius simulation. We use a matched filter approach to look for 'gaps' in tidal streams at 12 length scales from 0.1 kpc to 5 kpc, which appear as characteristic dips in the linear densities along the streams. We find that, in addition to the subhalos' perturbations, the epicyclic overdensities (EOs) due to the coherent epicyclic motions of particles in a stream also produce gap-like signals near the progenitor. We measure the gap spectra—the gap formation rates as functions of gap length—due to both subhalo perturbations and EOs, which have not been accounted for together by previous studies. Finally, we project the simulated streams onto the sky to investigate issues when interpreting gap spectra in observations. In particular, we find that gap spectra from low signal-to-noise observations can be biased by the orbitalmore » phase of the stream. This indicates that the study of stream gaps will benefit greatly from high-quality data from future missions.« less
Authors:
;  [1]
  1. Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S3H4 (Canada)
Publication Date:
OSTI Identifier:
22356537
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 788; 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; COSMOLOGICAL MODELS; DENSITY; DISTRIBUTION; DISTURBANCES; INTERACTIONS; MASS; MILKY WAY; NONLUMINOUS MATTER; PERTURBATION THEORY; SATELLITES; SIMULATION; SPECTRA; SPHERICAL CONFIGURATION; STAR CLUSTERS; STREAMS