Home List of Titles Formation and evolution of dwarf elliptical galaxies I: structural and kinematical properties
Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/55543
- Formation and evolution of dwarf elliptical galaxies I: structural and kinematical properties
- De Rijcke, S.; Michielsen, D.; Dejonghe, H.; Zeilinger, W. W.; Hau, G. K. T.
- This paper is the first in a series in which we present the results of an ESO Large Program on the kinematics and internal dynamics of dwarf elliptical galaxies (dEs). We obtained deep major and minor axis spectra of 15 dEs and broad-band imaging of 22 dEs, Here, we investigate the relations between the parameters that quantify the structure (B-band luminosity LB, half-light radius Re, and mean surface brightness within the half-light radius Ie = LB/2πRe2) and internal dynamics (velocity dispersion σ) of dEs. We confront predictions of the currently popular theories for dE formation and evolution with the observed position of dEs in log LB vs. log σ, log IB vs. log Ie, log Ie vs. log Ie, and log Re vs. log Ie diagrams and in the (log σ, log Re, log Ie) parameter space in which bright and intermediate-luminosity elliptical galaxies and bulges of spirals define a Fundamental Plane (FP). In order to achieve statistical significance and to cover a parameter interval that is large enough for reliable inferences to be made, we merge the data set presented in this paper with two other recently published, equally large data sets. We show that the dE sequences in the various univariate diagrams are disjunct from those traced by bright and intermediate-luminosity elliptical galaxies and bulges of spirals. It appears that semi-analytical models (SAMs) that incorporate quiescent star formation with an essentially z-independent star-formation efficiency, combined with post-merger starbursts and the dynamical response after supernova-driven gas-loss, are able to reproduce the position of the dEs in the various univariate diagrams. SAMs with star-formation efficiencies that rise as a function of redshift are excluded since they leave the observed sequences traced by dEs virtually unpopulated. dEs tend to lie above the FP and the FP residual declines as a function of luminosity. Again, models that take into account the response after supernova-driven mass-loss correctly predict the position of dEs in the (log σ, log Re, log Ie) parameter space as well as the trend of the FP residual as a function of luminosity. While these findings are clearly a success for the hierarchical-merging picture of galaxy formation, they do not necessarily invalidate the alternative "harassment" scenario, which posits that dEs stem from perturbed and stripped late-type disk galaxies that entered clusters and groups of galaxies about 5 Gyr ago.
- Publication type
- Journal article
- Astronomy and Astrophysics, Vol. 438, no. 2 (Aug 2005), pp. 491-505
- Publication year
- FOR Code(s)
- 0201 Astronomical and Space Sciences
- Astrophysics; Computer simulation; Data reduction; Dwarf galaxies; ESO; European Southern Observatory; Fundamental parameters of galaxies; Galaxy evolution; Galaxy formation; Galaxy kinematics and dynamics; Kinematics; Spectroscopic analysis; Surface treatment; Velocity
- EDP Sciences
- Publisher URL
- Copyright © ESO 2005.
- Additional information
- This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
- Peer reviewed