Journal Article

Stellar streams as probes of dark halo mass and morphology: a Bayesian reconstruction

A. Varghese, R. Ibata and G. F. Lewis

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 417, issue 1, pages 198-215
Published in print October 2011 | ISSN: 0035-8711
Published online October 2011 | e-ISSN: 1365-2966 | DOI:
Stellar streams as probes of dark halo mass and morphology: a Bayesian reconstruction

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Tidal streams provide a powerful tool by means of which the matter distribution of the dark matter haloes of their host galaxies can be studied. However, the analysis is not straightforward because streams do not delineate orbits, and for most streams, especially those in external galaxies, kinematic information is absent. We present a method wherein streams are fitted with simple corrections made to possible orbits of the progenitor, using a Bayesian technique known as parallel tempering to efficiently explore the parameter space. We show that it is possible to constrain the shape of the host halo potential or its density distribution using only the projection of tidal streams on the sky, if the host halo is considered to be axisymmetric. By adding kinematic data or the circular velocity curve of the host to the fitting data, we are able to recover other parameters of the matter distribution such as its mass and profile. We test our method on several simulated low-mass stellar streams and also explore the cases for which additional data are required.

Keywords: gravitation; dark matter

Journal Article.  12102 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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