EDP Sciences
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Volume 408, Number 1, September II 2003
Page(s) 141 - 151
Section Stellar clusters and associations
DOI http://dx.doi.org/10.1051/0004-6361:20030935

A&A 408, 141-151 (2003)
DOI: 10.1051/0004-6361:20030935

Stellar density distribution in the NIR on the Galactic plane at longitudes 15-27 deg. Clues for the Galactic bar?

S. Picaud1, A. Cabrera-Lavers2 and F. Garzón2, 3

1  CNRS UMR 6091, Observatoire de Besançon, BP 1615, 25010 Besançon Cedex, France
2  Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
3  Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain

(Received 6 March 2003 / Accepted 28 May 2003)

Garzón et al. (1997), López-Corredoira et al. (1999] and Hammersley et al. (2000) have identified in TMGS and DENIS data a large excess of stars at $l=27^{\circ}$ and $b=0^\circ$ which might correspond to an in-plane bar. We compared near infrared CAIN star counts and simulations from the Besançon Model of Galaxy on 15 fields between 15° and 45° in longitude and $-2^\circ$ and 2° in latitude. Comparisons confirm the existence of an overdensity at longitudes lower than 27° which is inhomogeneous and decreases very steeply off the Galactic plane. The observed excess in the star distribution over the predicted density is even higher than 100%. Its distance from the sun is estimated to be lower than 6 kpc. If this overdensity corresponds to the stellar population of the bar, we estimate its half-length to $3.9\pm0.4$ kpc and its angle from the Sun-center direction to $45\pm9$ degrees.

Key words: Galaxy: structure -- Galaxy: stellar content -- Galaxy: disk

Offprint request: S. Picaud, picaud@obs-besancon.fr

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© ESO 2003