Bibcode
López-Corredoira, M.; Hammersley, P. L.; Garzón, F.; Cabrera-Lavers, A.; Castro-Rodríguez, N.; Schultheis, M.; Mahoney, T. J.
Bibliographical reference
Astronomy and Astrophysics, v.373, p.139-152 (2001)
Advertised on:
7
2001
Journal
Citations
44
Refereed citations
36
Description
New evidence for a long thin Galactic bar (in contradistinction to the
bulge), as well as for the existence of the ring and the truncation of
the inner disc, are sought in the DENIS survey. First, we examine DENIS
and Two Micron Galactic Survey star counts for the characteristic
signatures of an in-plane bar and ring. The star counts in the plane for
30o>l>-30o are shown to be highly asymmetric
with considerably more sources at positive than at negative longitudes.
At |b|~ 1.5o, however, the counts are nearly symmetric.
Therefore, the asymmetry is not due to the disc, which is shown to have
an inner truncation, or to the bulge, so there has to be another major
component in the inner Galaxy that is causing the asymmetries. This
component provides up to 50% of the detected sources in the plane
between the bulge and l=27o or l=-14o. This
component is shown to be consistent with an in-plane bar with a position
angle of 40o and half-length of 3.9 kpc. However, there is
also a major peak in the counts at l=-22o, which coincides
with the tangential point of the so-called 3 kpc arm. This is shown to
be most probably a ring or a pseudo-ring. The extinction in the plane is
also shown to be asymmetric with more extinction at negative than at
positive longitudes. For l<8o the extinction is shown to
be slightly tilted with respect to b=0o in the same manner as
the HI disc. We conclude that the Galaxy is a fairly typical ringed
barred spiral galaxy.