The AAT/WFI survey of the Monoceros Ring and Canis Major Dwarf galaxy: I. from l = (193 - 276)o

Abstract

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 {\it 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. (Abridged)

22 pages, lots of figures (reduced in quality for astro-ph submission). Accepted for publication in MNRAS

References in corpus (8)

• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• Outer structure of the Galactic warp and flare: explaining the Canis Major over-density
• Detection of a 60 Degree-Long Dwarf Galaxy Debris Stream
• The Spiral Structure of the Outer Milky Way in Hydrogen
• Substructure in Tidal Streams; Tributaries in the Anticenter Ring
• A 22 Degree Tidal Tail for Palomar 5
• Spiral structure of the Third Galactic Quadrant and the solution to the Canis Major debate
• Galactic Warp in the overdensity of the Canis Major Region

Cited by in corpus (20)

• The Local Dark Matter Density
• Thin, thick and dark discs in LCDM
• Halo globular clusters observed with AAOmega: dark matter content, metallicity and tidal heating
• Detection of the Keplerian decline in the Milky Way rotation curve
• Revealing Substructure in the Galactic Halo - The SEKBO RR Lyrae Survey
• The Complex Structure of Stars in the Outer Galactic Disk as revealed by Pan-STARRS1
• On the Origin of Dynamically Cold Rings Around the Milky Way
• A search for stellar tidal debris of defunct dwarf galaxies around globular clusters in the inner Galactic halo
• No Excess of RR Lyrae Stars in the Canis Major Overdensity
• Reaffirming the connection between the Galactic stellar warp and the Canis Major overdensity
• Searching for spiral features in the outer Galactic disk. The field towards WR38 and WR38a
• The Metallicity of the Monoceros Stream
• The outer disc in shambles: blind detection of Monoceros and ACS with Gaia's astrometric sample
• Kinematics of Stars in Kapteyn Selected Area 71: Sampling the Monoceros and Sagittarius Tidal Streams
• A Sagittarius-Induced Origin for the Monoceros Ring
• On the Origin of the Monoceros Ring - I: Kinematics, proper motions, and the nature of the progenitor
• Disentangling the Galaxy at low Galactic latitudes
• A Megacam Survey of Outer Halo Satellites. IV. Two foreground populations possibly associated with the Monoceros substructure in the direction of NGC2419 and Koposov2
• The dark connection between the Canis Major dwarf, the Monoceros ring, the gas flaring, the rotation curve and the EGRET excess of diffuse Galactic Gamma Rays
• Indirect Dark Matter Signals