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Astron. Astrophys. Suppl. Ser. 133, 325-336

Extended stellar kinematics of elliptical galaxies in the Fornax cluster[*][*]

A.W. Graham 1 - M.M. Colless 1 - G. Busarello 2 - S. Zaggia 2 - G. Longo 2

Send offprint request: A.W. Graham,

1 - Mount Stromlo and Siding Spring Observatories, Australian National University, PMB Weston Creek PO, ACT 2611, Australia
2 - Osservatorio Astronomico di Capodimonte, via Moiariello 16, I-80131 Napoli, Italy

Received February 4; accepted June 17, 1998


We present extended stellar kinematics for a sample of elliptical galaxies in the Fornax cluster. Out of the 13 galaxies presented here, five (FCC 119, FCC 136, NGC 1373, NGC 1428, FCC 335) have no previously published kinematical data. Major-axis velocity dispersion profiles (VDPs) and rotation curves (RCs) are given for 12 of the galaxies. A major feature of this data is the spatial extension: for 8 galaxies the data extends beyond 1 $R_{\rm e}$, and for 5 it extends beyond 2 $R_{\rm e}$.Compared to the previously available data, this corresponds to an increase in spatial coverage by a factor from 1 to 5. The present sample represents 86% of the ellipticals in Fornax brighter than $B_{\rm T}$ = 15 mag.

Five of the ellipticals in the sample turn out to be rotationally-supported systems, having positive rotation parameter $\log (\frac{V}{\sigma})^*$.One of these five, and another 3 galaxies from the remaining sample, display evidence for bar-like kinematics.

The data indicate that the true number of "dynamically hot'' stellar systems, is much lower than previously thought: of the Es in the present sample only 1/4 are confirmed as "pressure-supported'' systems.

The data reveal a host of individual peculiarities, like: wiggles, strong gradients, and asymmetries in the rotation curve and/or in the velocity dispersion profile, thus showing that the presence of kinematically distinct components and/or triaxiality is a common characteristic of this class of object.

Key words: galaxies: kinematics and dynamics -- galaxies: elliptical and lenticular, cD -- galaxies: clusters: individual: Fornax -- galaxies: structure -- galaxies: fundamental parameters

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