Abstract details

The Canis Major overdensity (CMa) was initially proposed to be the remnant of a dSph galaxy in an advanced stage of destruction due to the tidal forces of the Milky Way. However, the nature of CMa is subject of ongoing debate. The CMa overdensity has also been proposed to be signature of the Galactic Warp seen in projection, an outlying part of the larger Argo feature, as well as part of the Outer (Norma-Cygnus) spiral arm. Given the ongoing controversy, the goal of the present work was to conduct a large-scale RR Lyrae survey in CMa, in order to determine the presence or absence of an overdensity of these old, metal-poor stars. The survey spans a total area of $\sim34$sqdeg with observations in V and R filters, made with the 1.0m J\"urgen Stock Schmidt telescope at the National Astronomical Observatory of Venezuela. Spectroscopic follow-up of a subset of the RR Lyrae stars has been obtained. Current results in a subregion show that the small number of RR Lyrae stars found can be accounted for by the halo and thick disk components of our Galaxy.