EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 421/2 Article
Free access article

Issue A&A
Volume 421, Number 2, July II 2004
Page(s) L29 - L32
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20040183



A&A 421, L29-L32 (2004)
DOI: 10.1051/0004-6361:20040183

Letter

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

Y. Momany1, S. R. Zaggia2, P. Bonifacio2, G. Piotto1, F. De Angeli1, L. R. Bedin1 and G. Carraro1

1  Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, 35122 Padova, Italy
    e-mail: [momany;piotto;carraro;deangeli;bedin]@pd.astro.it
2  INAF - Osservatrio Astronomico di Trieste, via Tiepolo 11, 34131 Trieste, Italy
    e-mail: [zaggia;bonifacio]@ts.astro.it

(Received 20 April 2004 / Accepted 25 May 2004 )

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. 2004, MNRAS, 348, 12; Bellazzini et al. 2004, [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. 2003, 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. 2002, ApJ, 569, 245; Yanny et al. 2003, ApJ, 588, 824).


Key words: astrometry -- Galaxy: structure -- Galaxy: formation -- Galaxies: interactions

SIMBAD Objects



© ESO 2004


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.