A dwarf galaxy remnant in Canis Major: the fossil of an in-plane accretion on to the Milky Way

  title={A dwarf galaxy remnant in Canis Major: the fossil of an in-plane accretion on to the Milky Way},
  author={Nicolas F. Martin and Rodrigo A. Ibata and Michele Bellazzini and Michael J. Irwin and Geraint F. Lewis and Walter Dehnen},
  journal={Monthly Notices of the Royal Astronomical Society},
We present an analysis of the asymmetries in the population of Galactic M-giant stars present in the 2MASS All Sky catalogue. Several large-scale asymmetries are detected, the most significant of which is a strong elliptical-shaped stellar over-density, close to the Galactic plane at (l = 240 ◦ , b = 8 ◦ ), in the constellation of Canis Major. A small grouping of globular clusters (NGC 1851, NGC 1904, NGC 2298, and NGC 2808), coincident in position and radial velocity, surround this structure… 
A search for stellar tidal debris of defunct dwarf galaxies around globular clusters in the inner Galactic halo
In the hierarchical formation scenario in which the outer halo of the Milky Way is the result of the continuous accretion of low-mass galaxies, a fraction of the Galactic globular cluster system
On the Accretion Origin of a Vast Extended Stellar Disk around the Andromeda Galaxy
We present the discovery of an inhomogenous, low surface brightness, extended disklike structure around the Andromeda galaxy (M31) based on a large kinematic survey of more than 2800 stars with the
The core of the Canis Major galaxy as traced by red clump stars
The recently discovered stellar system in Canis Major is analysed using He-burning red clump stars as tracers. Canis Major turns out to be the strongest and the most spatially confined overdensity of
Spiral structure of the third galactic quadrant and the solution to the Canis Major debate
ABSTRACT With the discovery of the Sagittarius dwarf spheroidal (Ibata et al. 1994), a galaxycaught in the process of merging with the Milky Way, the hunt for other such ac-cretion events has become
The Galaxy and its stellar halo: insights on their formation from a hybrid cosmological approach
We use a series of high-resolution simulations of a 'Milky Way' halo coupled to semi-analytic methods to study the formation of our own Galaxy and its stellar halo. The physical properties of our
Galactic structure in the outer disk: the field in the line of sight to the intermediate-age open cluster Tombaugh 1
We employ optical photometry and high-resolution spectroscopy to study a field toward the open cluster Tombaugh 1, where we identify a complex population mixture, that we describe in terms of young
A radial velocity survey of low Galactic latitude structures – II. The Monoceros Ring behind the Canis Major dwarf galaxy
An AAT/2dF Spectrograph Survey of low Galactic latitudes targeting the putative Canis Major dwarf galaxy and the (possibly) associated tidal debris of stars known as the Monoceros Ring, covering
The Chemical Evolution of the Monoceros Ring/Galactic Anticenter Stellar Structure
The origin of the Galactic Anticenter Stellar Structure (GASS) or "Monoceros Ring"—a low-latitude overdensity at the edge of the Galactic disk spanning at least the second and third Galactic
A Pilot Survey of Stellar Tidal Streams in Nearby Spiral Galaxies
Within the hierarchical framework for galaxy formation, merging and tidal interactions are expected to shape large galaxies to this day. While major mergers are quite rare at present, minor mergers
The Complex Structure of Stars in the Outer Galactic Disk as Revealed by Pan-STARRS1
We present a panoptic view of the stellar structure in the Galactic disk's outer reaches commonly known as the Monoceros Ring, based on data from Pan-STARRS1. These observations clearly show the


Substructure of the outer Galactic halo from the 2-Micron All-Sky Survey
A pole-count analysis of the infrared 2-Micron All-Sky (2MASS) survey is presented, in order to identify faint stream-like great-circle structures within the halo of the Milky Way. Selecting stars
Tracing the Galactic Anticenter Stellar Stream with 2MASS M Giants
The recently discovered, ringlike structure just outside the Galactic disk in Monoceros is detected and traced among 2MASS M giant stars. We have developed a method to recover the signature of this
Great Circle Tidal Streams: Evidence for a Nearly Spherical Massive Dark Halo around the Milky Way
An all-high-latitude sky survey for cool carbon giant stars in the Galactic halo has revealed 75 such stars, of which the majority are new detections. Of these, more than half are clustered on a
The Ghost of Sagittarius and Lumps in the Halo of the Milky Way
We identify new structures in the halo of the Milky Way from positions, colors, and magnitudes of five million stars detected in the Sloan Digital Sky Survey. Most of these stars are within 126 of
Simulations of Galaxy Formation in a Λ Cold Dark Matter Universe. II. The Fine Structure of Simulated Galactic Disks
We present a detailed analysis of the disk component of a simulated galaxy formed in the ΛCDM cosmogony. At redshift z = 0, two distinct dynamical components are easily identified solely on the basis
The Kinematics, Orbit, and Survival of the Sagittarius Dwarf Spheroidal Galaxy
The Sagittarius galaxy (Sgr), the closest satellite galaxy of the Milky Way, has survived for many orbits about the Galaxy. Extant numerical calculations modeled this galaxy as a system with a
Building Up the Globular Cluster System of the Milky Way: The Contribution of the Sagittarius Galaxy
We demonstrate that there is a clear statistical correlation between the (X, Y, Z, Vr) phase-space distribution of the outer halo Galactic globular clusters (having 10 kpc ≤ RGC ≤ 40 kpc) and the
Galactic Indigestion: Numerical Simulations of the Milky Way's Closest Neighbor
Are dwarf spheroidal galaxies dark matter dominated? We present N-body simulations of the interaction between the Milky Way and its closest companion, the Sagittarius dwarf spheroidal galaxy,
One ring to encompass them all: a giant stellar structure that surrounds the Galaxy
Evidence is presented that the curious stellar population found by the Sloan Digital Sky Survey in the Galactic anticentre direction extends to other distant fields that skirt the plane of the Milky Way, suggesting that the outer rim of the Galaxy ends in a low surface brightness stellar ring.
A Low-Latitude Halo Stream around the Milky Way
We present evidence for a ring of stars in the plane of the Milky Way, extending at least from l = 180° to 227° with turnoff magnitude g ~ 19.5; the ring could encircle the Galaxy. We infer that the