Detection of the old stellar component of the major Galactic bar |
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| Authors: | P L Hammersley F Garzón T J Mahoney M López-Corredoira M A P Torres |
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| Institution: | Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain;Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Tenerife, Spain |
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| Abstract: | 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°. |
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| Keywords: | Galaxy: stellar content Galaxy: structure infrared: stars |
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