Bibcode
Cabrera-Lavers, A.; Hammersley, P. L.; González-Fernández, C.; López-Corredoira, M.; Garzón, F.; Mahoney, T. J.
Bibliographical reference
Astronomy and Astrophysics, Volume 465, Issue 3, April III 2007, pp.825-838
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4
2007
Journal
Citations
109
Refereed citations
94
Description
Context: Over the last decade a series of results have lent support to
the hypothesis of the existence of a long thin bar in the Milky Way with
a half-length of 4.5 kpc and a position angle of around 45°. This is
apparently a very different structure from the triaxial bulge of the
Galaxy. Aims: In this paper, we analyse the stellar distribution
in the inner 4 kpc of the Galaxy to see if there is clear evidence for
two triaxial or barlike structures, or whether there is only one. Methods: By using the red-clump population as a tracer of the
structure of the inner Galaxy we determine the apparent morphology of
the inner Galaxy. Star counts from 2MASS are used to provide additional
support for this analysis. Results: We show that there are two
very different large-scale triaxial structures coexisting in the inner
Galaxy: a long thin stellar bar constrained to the Galactic plane
(|b|<2°) with a position angle of 43.0 ° ± 1.8 °,
and a distinct triaxial bulge that extends to at least |b|≤7.5°
with a position angle of 12.6 ° ± 3.2 °. The scale height
of the bar source distribution is around 100 pc, whereas for the bulge
the value of this parameter is five times larger.