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Astron. Astrophys. 326, 897-906 (1997)

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Near-infrared surface photometry of spiral galaxies *

II. Derivation of mass models

Ph. Héraudeau and F. Simien

CRAL-Observatoire de Lyon, F-69561 Saint-Genis-Laval Cedex, France

Received 3 June 1996 / Accepted 9 May 1997


Near-infrared surface photometry of six spiral galaxies is used to separate the main stellar components and derive mass models whose predicted rotation curves are compared to observed gas kinematics. For three of the galaxies, central stellar velocity dispersions are also used. For these intrinsically bright objects, the mass-to-light ratio of the disk, in the K band, is found to be [FORMULA], as expected. In four Sb-Sc galaxies, there is some evidence that the mass-to-light ratio of the bulge may be on average [FORMULA] % smaller, but the a priori assumption that these ratios are identical does not significantly bias the disk masses. Early-type spirals with a prominent bulge, in which the apparent central mass-to-light ratio is known to be often low, can need a significant correction to the bulge mass.

Key words: galaxies: spiral – galaxies: photometry – galaxies: kinematics and dynamics – infrared: galaxies – galaxies: structure

* Based in part on observations collected at the European Southern Observatory, La Silla, Chile, and at the Observatoire de Haute-Provence, France.

Send offprint requests to: F. Simien (simien@obs.univ-lyon1.fr)

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© European Southern Observatory (ESO) 1997

Online publication: April 8, 1998