Probing the Canis Major stellar over-density as due to the Galactic warp

2004/05/26 by Y. Momany, S. Zaggia, P. Bonifacio +4 · 6 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Disc #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #K-type main-sequence star #Milky Way #Physics #Proper motion #Satellite galaxy #Star cluster #Star count #Stars #Stellar density #Stellar kinematics #Stellar, planetary, and galactic studies #T Tauri star #Thick disk #astro-ph

paper · pdf · doi:10.1051/0004-6361:20040183

published as Astron.Astrophys. 421 (2004) L29-L32 · Accepted for publication in A&A Letters, 4 pages

arxiv created 2004/05/26 · openalex publication_date 2004/06/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

Proper-motion, star counts and photometric catalog simulations are used to explain the detected stellar over-density in the region of Canis Major, claimed to be the core of a disrupted dwarf galaxy (CMa, Martin et al. [CITE], MNRAS, 348, 12; Bellazzini et al. [CITE], [arXiv:astro-ph/0311119]), as due to the Galactic warp and flare in the external disk. We compare the kinematics of CMa M-giant selected sample with surrounding Galactic disk stars in the UCAC2 catalog and find no peculiar proper motion signature: CMa stars mimic thick disk kinematics. Moreover, when taking into account the Galactic warp and flare of the disk, 2MASS star count profiles reproduce the CMa stellar over-density. This star count analysis is confirmed by direct comparison with synthetic color-magnitude diagrams simulated with the Besançon models (Robin et al. [CITE], A&A, 409, 523) that include the warp and flare of the disk. The presented evidence casts doubt on the identification of the CMa over-density as the core of a disrupted Milky Way satellite. This however does not make clear the origin of over-densities responsible for the ring structure in the anticenter direction of the Galactic halo (Newberg et al. [CITE], ApJ, 569, 245; Yanny et al. 2003, ApJ, 588, 824).

Citations

• Detection of the Canis Major galaxy at (l;b) = (244°; −8°) and in the background of Galactic open clusters
• A Low‐Latitude Halo Stream around the Milky Way
• Star Clusters in the Galactic Anticenter Stellar Structure and the Origin of Outer Old Open Clusters
• The Globular Cluster System of the Canis Major Dwarf Galaxy
• Simulations of Galaxy Formation in a Λ Cold Dark Matter Universe. I. Dynamical and Photometric Properties of a Simulated Disk Galaxy
• The Second US Naval Observatory CCD Astrograph Catalog (UCAC2)

Cited by

• The old anticentre open cluster Berkeley 32: membership and fundamental parameters
• A revised view of the Canis Major stellar overdensity with DECam and Gaia: new evidence of a stellar warp of blue stars
• Exploring the Perturbed Milky Way Disk and the Substructures of the Outer Disk
• Tombaugh 2: the first open cluster with a significant abundance spread or embedded in a cold stellar stream?★
• Comparing the properties of local globular cluster systems: implications for the formation of the Galactic halo
• A study of the Galactic plane towardsl= 305°