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Astron. Astrophys. 319, 435-449 (1997)

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Kinematics of the local universe

IV. Type dependence in the diameter Tully-Fisher relation and implications
on the mass-luminosity structure

G. Theureau 1, M. Hanski 2, P. Teerikorpi 2, L. Bottinelli 1, 3, T. Ekholm 2, L. Gouguenheim 1, 3 and G. Paturel 4

1 Observatoire de Paris-Meudon, CNRS URA1757, F-92195 Meudon Principal Cedex, France
2 Tuorla Observatory, FIN-21500 Piikkiö, Finland
3 Université Paris-Sud, F-91405 Orsay, France
4 Observatoire de Lyon, F-69230 Saint-Genis Laval, France

Received 8 December 1995 / Accepted 14 August 1996


There is a type dependence in the diameter (Tully-Fisher) TF relation in the spiral galaxy range [FORMULA]. This dependence appears as a zero-point shift from one type to another, while the slope seems to remain constant, close to 0.5 (inverse relation) as expected from our simple disc + bulge + dark halo model. The model also predicts well the amount of the shifts, when reasonable values of the mass-to-luminosity ratios of the disc and bulge components are used. A method to study the dark mass fraction [FORMULA] in different galaxy types, based on the model, is introduced. First applications suggest that in the range [FORMULA] the value of [FORMULA] within the radius [FORMULA] that the TF-measurements refer to. There are also zero-point shifts in the B -magnitude TF-relation (the inverse slope [FORMULA] 0.1 according to our work), though smaller than in the diameter relation, as expected from the model. The found type dependencies will diminish the scatter in the TF-relations and facilitate their use in our KLUN programme for measuring the kinematics of the local galaxy universe.

Key words: galaxies: spiral – galaxies: photometry – galaxies: distances and redshifts – galaxies: structure – astronomical data bases: miscellaneous

Send offprint requests to: G. Theureau


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© European Southern Observatory (ESO) 1997

Online publication: July 3, 1998