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

S. Picaud (1) , A. Cabrera-Lavers (2) , F. Garzon (2)

1 LAOB - Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091)
2 IAC - Instituto de Astrofisica de Canarias

Garzon et al. (1997), Lopez-Corredoira et al. (1999) and Hammersley et al. (2000)have identified in TMGS and DENIS data a large excess of stars at l=27 deg andb=0 deg which might correspond to an in-plane bar. We compared near infraredCAIN star counts and simulations from the Besancon Model of Galaxy on 15 fieldsbetween 15 deg and 45 deg in longitude and -2 deg and 2 deg in latitude.Comparisons confirm the existence of an overdensity at longitudes lower than 27deg which is inhomogeneous and decreases very steeply off the Galactic plane.The observed excess in the star distribution over the predicted density is evenhigher than 100%. Its distance from the sun is estimated to be lower than 6kpc. If this overdensity corresponds to the stellar population of the bar, weestimate its half-length to 3.9 +/ -0.4 kpc and its angle from the Sun-centerdirection to 45 +/- 9 degrees.

Mots clés: Galaxy: structure; Galaxy: stellar content; Galaxy: disk

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

S. Picaud, A. Cabrera-Lavers, F. Garzon. Stellar density distribution in the NIR on the Galactic plane at longitudes 15-27 deg. Clues for the Galactic bar ?. 2003. ⟨hal-00000461⟩