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arXiv · 1011.3665

Optical and near-infrared velocity dispersions of early-type galaxies

Joachim Vanderbeke·Maarten Baes·Aaron J. Romanowsky·Linda Schmidtobreick
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Abstract

We have carried out a systematic, homogeneous comparison of optical and near-infrared dispersions. Our magnitude-limited sample of early-type galaxies in the Fornax cluster comprises 11 elliptical and 11 lenticular galaxies more luminous than MB = -17. We were able to determine the central dispersions based on the near-infrared CO absorption band head for 19 of those galaxies. The velocity dispersions range from less than 70 km/s to over 400 km/s. We compare our near-infrared velocity dispersions to the optical dispersions measured by Kuntschner (2000). Contrary to previous studies, we find a one-to-one correspondence with a median fractional difference of 6.4%. We examine the correlation between the relative dust mass and the fractional difference of the velocity dispersions, but find no significant trend. Our results suggest that early-type galaxies are largely optically thin, which is consistent with recent Herschel observations.

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Joachim Vanderbeke, Maarten Baes, Aaron J. Romanowsky, Linda Schmidtobreick. 2010-11-16. Optical and near-infrared velocity dispersions of early-type galaxies. https://doi.org/10.1111/j.1365-2966.2010.18036.x

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