We present the results of an AAT wide-field camera survey of the stars in the Monoceros Ring and purported Canis Major overdensity in the Galactic longitudes of l = ( 193 - 276 ) ^ { \circ } .
Current numerical simulations suggest that both of these structures are the result of a single on-going accretion event , although an alternative solution is that the warped and flared disc of the Galaxy can explain the origin of both of these structures .
Our results show that , with regards the Monoceros Ring , the warped and flared disc is unable to reproduce the locations and strengths of the detections observed around the Galaxy .
This supports a non-Galactic origin for this structure .
We report 8 new detections and 2 tentative detections of the Monoceros Ring in this survey .
The exact nature of the Canis Major overdensity is still unresolved although this survey provides evidence that invoking the Galactic warp is not a sufficient solution when compared with observation .
Several fields in this survey are highly inconsistent with the current Galactic disc models that include a warp and flare , to such an extent that explaining their origins with these structures is problematic .
We also report that the Blue Plume stars previously invoked to support the dwarf galaxy hypothesis is unfounded , and associating them with an outer spiral arm is equally problematic .
Standard Galactic models are unable to accommodate all the observations of these new structures , leading away from a warped/flared disc explanation for their origins and more toward a non-Galactic source .
Additionally , evidence is presented in favour of a detection of the Canis Major dwarf stream away from the Canis Major region .
As the outer reaches of the Galactic disc continue to be probed , the fascinating structures that are the Monoceros Ring and Canis Major overdensity will no doubt continue to inform us of the unique structure and formation of the Milky Way .