Issue |
A&A
Volume 559, November 2013
|
|
---|---|---|
Article Number | A11 | |
Number of page(s) | 14 | |
Section | Galactic structure, stellar clusters and populations | |
DOI | https://doi.org/10.1051/0004-6361/201219846 | |
Published online | 29 October 2013 |
The long bar as seen by the VVV Survey
II. Star counts⋆
1
UEFS, Departamento de Física, Av. Transnordestina, S/N, Novo Horizonte,
CEP 44036-900, Feira de Santana, Brazil
e-mail:
ebamores@uefs.br
2
UEFS, Observatório Astronômico Antares,
Rua da Barra, 925, Jardim
Cruzeiro, CEP
44024-432, Feira de
Santana, Brazil
3
SIM, Faculdade de Ciências da Universidade de
Lisboa, Ed. C8. Campo
Grande, 1749-016
Lisbon,
Portugal
4
IAC, vía Láctea
s/n, 38200
La Laguna ( Tenerife), Spain
5
Departamento de Astrofísica, Universidad de La
Laguna, 38206, La
Laguna, Tenerife,
Spain
6
Departamento de Física, Ingeniería de Sistemas y Teoría de la
Señal, Universidad de Alicante, Apdo. 99, 03080
Alicante,
Spain
7
Departamento Astronomía y Astrofísica, Pontificia Universidad
Católica de Chile, Av. Vicuña
Mackenna 4860, Santiago, Chile
8
Vatican Observatory, 00120
Vatican City State,
Italy
9
Departamento de Ciencias Físicas, Universidad Andres
Bello, 8370134
Santiago,
Chile
10
Observatorio Astronómico de Córdoba, Universidad Nacional de
Córdoba, Laprida
854, 5000
Córdoba,
Argentina
11
Instituto de Astronomía Teórica y Experimental
(IATE-CONICET), Laprida 922
X5000 BGR Córdoba,
Argentina
Received: 20 June 2012
Accepted: 20 June 2013
Context. There is still some debate about the presence and the morphological properties of the long bar in the inner Galaxy.
Aims. We investigate the morphological properties of the long Galactic bar using the VVV survey extending star counts at least 3 mag deeper than 2MASS. Our study covers the relatively unexplored negative longitudes of the Galactic bar. We obtain a detailed description of the spatial distribution of star counts towards the long Galactic bar as well as to measure its parameters.
Methods. We performed star counts towards −20° < ℓ < 0, |b|≤ 2° using VVV, 2MASS, and GLIMPSE data. We applied an average interstellar extinction correction. We also adjusted latitudinal profiles to obtain the centroid variation and bar thickness.
Results. We probe the structure of long Galactic bar, as well as its far edge at ℓ ≈ −14°. The differences between counts with and without extinction correction allow us to produce a crude extinction map showing regions with high extinction, mainly beyond the end of long Galactic bar. The latitudinal profiles show evidence of the centroid vertical variation with Galactic longitude reaching a minimum at ℓ ≈ −13.8°. The bar has an inclination angle α = 43° ± 5° with respect to the line Sun-Galactic center. In addition, we have determined the bar parameters, such as thickness, length, and stellar distribution.
Key words: ISM: structure / dust, extinction / Galaxy: stellar content / Galaxy: structure / Galaxy: center / Galaxy: general
Appendix A is available in electronic form at http://www.aanda.org
© ESO, 2013
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