Line-of-sight velocity distributions of low-luminosity elliptical galaxies |
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Authors: | C Halliday † Roger L Davies Harald Kuntschner M Birkinshaw Ralf Bender RP Saglia Glenn Baggley |
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Institution: | 1Department of Physics, University of Durham, Science Labs, South Road, Durham DH1 3LE;2H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL;3Universitäts-Sternwarte, Scheinerstr. 1, D-81679 München, Germany |
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Abstract: | The shape of the line-of-sight velocity distribution (LOSVD) is measured for a sample of 14 elliptical galaxies, predominantly low-luminosity ellipticals. The sample is dominated by galaxies in the Virgo cluster but also contains ellipticals in nearby groups and low-density environments. The parametrization of the LOSVD given by Gerhard and van der Marel & Franx is adopted, which measures the asymmetrical and symmetrical deviations of the LOSVD from a Gaussian by the amplitudes h 3 and h 4 of the Gauss–Hermite series. Rotation, velocity dispersion, h 3 and h 4 are determined as a function of radius for both major and minor axes. Non-Gaussian LOSVDs are found for all galaxies along the major axes. Deviations from a Gaussian LOSVD along the minor axis are of much lower amplitude if present at all. Central decreases in velocity dispersion are found for three galaxies. Two galaxies have kinematically decoupled cores: NGC 4458 and the well-known case of NGC 3608. |
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Keywords: | galaxies: elliptical and lenticular cD galaxies: formation galaxies: kinematics and dynamics |
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