Institute of Astronomy

Canis Major overdensity and Monoceros ring explained in terms of pure Milky Way structure

SpeakerTalk DateTalk Series
Martin Lopez Corredoira9 May 2014Institute of Astronomy Galaxies Discussion Group

Abstract

Some authors have suggested the existence of a nearby dwarf galaxy associated to the Canis Major overdensity, which was tidally disrupted leaving remnants throughout the Monoceros ring observed along several positions within ~20 degrees from the Galactic plane. Here, we present arguments to think
that the Canis Major overdensity is just a part of the Galactic warp+flare, instead of a dwarf galaxy or a new substructure in the Galaxy, and the Monoceros ring overdensities and its features on color-magnitude diagrams are mainly populations of the most external non-truncated flared thin+thick stellar disc. Failures to fit these features with the Milky structure stem mainly from the use of Galactic models which do not represent appropriately the southern warp, the disc flare, and that set an unrealistic truncation of the stellar populations of the disc at R>=14 kpc, like the Besançon model.

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