Tidal Dwarf Galaxies Bonn 2009: Ghosts from structure formation

Physics Centre Bad Honnef (Germany), May 25-29, 2009

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Talk

Title: Complex L - an H i structure shed by the Sagittarius dwarf galaxy?

Date: Thursday 28th May

Time: 16:45 - 17:15

Presentation file: talk_Jin.pdf

Abstract:

The tidal stellar stream of the Sagittarius (Sgr) dwarf galaxy is the most significant accretion event of a satellite galaxy onto the Galactic stellar halo. Traced through multiple orbital wraps, it provides important clues to both the formation of the Milky Way’s stellar halo and the shape of its dark matter halo. I will present a novel approach that exploits the large angular extent over which stellar radial velocities are known. Using the gradient in radial velocity along the tidal stream, one can calculate the transverse velocity for a given location on the stream as a function of distance (Jin & Lynden-Bell, 2007). Applying this technique to the trailing stream of Sgr results in an orbit that reproduces well what is currently known about the Sgr stream. It also reveals surprisingly good agreement with the H i structure Complex L if the latter is placed at ∼ 40 kpc, highlighting the possibility that some HVCs could have been brought into the Galactic halo through recent accretion events.

photos by Julia T. Scho (ForeignLight.com) / Marcel S. Pawlowski