Open AccessDetection of the old stellar component of the major Galactic bar
Author(s) -
Hammersley P. L.,
Garzón F.,
Mahoney T. J.,
LópezCorredoira M.,
Torres M. A. P.
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03858.x
Subject(s) - physics , astrophysics , bulge , stars , galactic plane , astronomy , galactic center , bar (unit) , star count , red clump , longitude , line (geometry) , line of sight , diagram , latitude , k type main sequence star , geometry , t tauri star , meteorology , statistics , mathematics
We present near‐infrared colour–magnitude diagrams and star counts for a number of regions along the Galactic plane. It is shown that along the l =27°, b =0° line of sight there is a feature at 5.7±0.7 kpc with a density of stars at least a factor of 2 and probably more than a factor of 5 times that of the disc at the same position. This feature forms a distinct clump on an H versus J − H diagram and is seen at all longitudes from the bulge to about l =28°, but at no longitude greater than this. The distance to the feature at l =20° is about 0.5 kpc further than at l =27°, and by l =10° it has merged with, or has become, the bulge. Given that at l =27° and l =21° there is also a clustering of very young stars, the only component that can reasonably explain what is seen is a bar with half‐length of around 4 kpc and a position angle of about 43°±7°.