Based on new observations collected at the European Southern Observatory, Cerro Paranal, Chile; ESO programme 082.B-0897A.
Optical and near-infrared velocity dispersions of early-type galaxies★
Article first published online: 26 JAN 2011
© 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS
Monthly Notices of the Royal Astronomical Society
Volume 412, Issue 3, pages 2017–2025, April 2011
How to Cite
Vanderbeke, J., Baes, M., Romanowsky, A. J. and Schmidtobreick, L. (2011), Optical and near-infrared velocity dispersions of early-type galaxies. Monthly Notices of the Royal Astronomical Society, 412: 2017–2025. doi: 10.1111/j.1365-2966.2010.18036.x
- Issue published online: 4 APR 2011
- Article first published online: 26 JAN 2011
- Accepted 2010 November 16. Received 2010 November 15; in original form 2010 August 31
- galaxies: clusters: individual: Fornax;
- galaxies: elliptical and lenticular, cD;
- galaxies: kinematics and dynamics
We have carried out a systematic, homogeneous comparison of optical and near-infrared dispersions. Our magnitude-limited sample of early-type galaxies (ETGs) 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−1 to over 400 km s−1. We compare our near-infrared velocity dispersions to the optical dispersions measured by Kuntschner. Contrary to previous studies, we find a one-to-one correspondence with a median fractional difference of 6.4 per cent. 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.