Bibcode
Prada, F.; Gutiérrez, C. M.
Bibliographical reference
Galaxy Interactions at Low and High Redshift, Proceedings of IAU Symposium #186, held at Kyoto, Japan, 26-30 August, 1997. Edited by J. E. Barnes, and D. B. Sanders, 1999., p.161
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1999
Citations
0
Refereed citations
0
Description
There is an increasing observational evidence of the presence of
retrograde motions in ellipticals and early type spiral galaxies.
However, little is known about this phenomenon in barred and late
ordinary spirals. Here, we present the current status of an on-going
research programme at the Observatorio del Roque de los Muchachos (La
Palma) to establish the presence and nature of the counterrotating
phenomenon across the Hubble sequence. We report the discovery of a warm
counterrotating component in the central regions of the late spiral NGC
7331 and the barred NGC 5728 galaxies. The stellar line-of-sight
velocity distribution was determined using near-IR long-slit
spectroscopy of the calcium triplet absorption feature with the William
Herschel Telescope. In NGC 7331 we find the first case of a
counterrotating bulge, while in NGC 5728 a central counterrotating
component was discovered in a barred galaxy. These results show that
retrograde motion extends throughout the Hubble sequence. The
implications of this in the context of the theories of galaxy formation
are discussed.