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Todays Colloquium: Seeing Sagittarius through the bulge: tracing stellar-stream stars in OGLE

Submitter: Shoko Jin (Kapteyn Institute)
Description: Satellite galaxies and stellar streams are important objects for studying the hierarchical assembly and evolution of their host galaxies, as well as for their potential to help uncover the mass distribution of their host's dark-matter halo. Located behind the Galactic bulge, the Sagittarius (Sgr) dwarf galaxy, together with its stellar stream that wraps multiple times around our Galaxy, is a prime example of such a system that is being tidally destroyed by our Galaxy.

Among the stars monitored by the Optical Gravitational Lensing Experiment (OGLE) for micro-lensing events towards the bulge are RR Lyrae stars, most of which belong to the bulge, but some of which clearly belong to another system, namely the Sgr stream. I will present a new analysis of this data set showing not only the Galactic bulge as seen through these tracers, but also the Sgr stellar stream that is serendipitously aligned along our line of sight towards the Galactic centre.
Copyright: Shoko Jin
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