Institute of Astronomy

Finding the Remains of Murdered Haloes and Galaxies: The Streams Going Notts Comparison Study

SpeakerTalk DateTalk Series
Pascal Elahi, Shanghai Astronomical Observatory30 November 2012Institute of Astronomy Galaxies Discussion Group

Abstract

Deep observations show that galaxies have turbulent lives. Some are even completely destroyed such as the Sagittarius stream. Such events are not expected as galaxies simulations show dark matter haloes, which host these galaxies, grow by accreting other haloes and contain a wealth of substructure. Most studies typically focus on intact subhaloes and their luminous counterparts, satellite galaxies. Yet tidal remnants provide another avenue to test the current paradigm of structure formation. Dark matter tidal streams may constitute an important component of our Halo and their properties have important ramifications for direct dark matter detectors. Stellar streams provide a means of doing Galactic Archeology. Unfortunately, the stream content of haloes from cosmological simulations is unknown simply due to the fa! ct that many object finders used to identify subhaloes cannot be used to detect streams. Here I will present the first study examining how well the few code capable of, in principle, identifying streams,such as my own algorithm, recover streams. I will also present preliminary work on how dark matter streams contribute to the make-up of a halo. Time permitting, I will also discuss how these techniques could be adapted to observational searches for stellar streams, which of great relevance for upcoming missions such as GAIA.

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