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Astron. Astrophys. 346, 13-32 (1999)

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Probing early-type galaxy evolution with the Kormendy relation *

B.L. Ziegler **  1, R.P. Saglia 1, R. Bender 1, P. Belloni ***  1, L. Greggio 1,2 and S. Seitz 1

1 Universitäts-Sternwarte, Scheinerstrasse 1, D-81679 München, Germany (ziegler@usm.uni-muenchen.de)
2 Dipartimento di Astronomia, Via Zamboni 33, I-40100 Bologna, Italy

Received 17 July 1998 / Accepted 5 March 1999


We investigate the evolution of early-type galaxies in four clusters at [FORMULA] (Abell 370 , Cl 0303+17 , Cl 0939+47 and Cl 1447+26 ) and in one at [FORMULA] (Cl 0016+16 ). The galaxies are selected according to their spectrophotometrically determined spectral types and comprise the morphological classes E, S0 and Sa galaxies. Structural parameters are determined by a two-component fitting of the surface brightness profiles derived from HST images. Exploring a realistic range of K-corrections using Bruzual and Charlot models, we construct the rest-frame B-band Kormendy relations ([FORMULA]) for the different clusters. We do not detect a systematic change of the slope of the relation as a function of redshift. We discuss in detail how the luminosity evolution, derived by comparing the Kormendy relations of the distant clusters with the local one for Coma, depends on various assumptions and give a full description of random and systematic errors by exploring the influences of selection bias, different star formation histories and K-corrections.

Early-type galaxies with modest disk components (S0 and Sa) do not differ significantly in their evolution from disk-less ellipticals.

The observed luminosity evolution is compatible with pure passive evolution models (with redshift of formation [FORMULA]) but also with models that allow ongoing star formation on a low level, like exponentially decaying star formation models with an e-folding time of [FORMULA] Gyr.

Key words: galaxies: clusters: general – galaxies: elliptical and lenticular, cD – galaxies: evolution – galaxies: formation – galaxies: fundamental parameters

* Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.
** Present Address: Department of Physics, South Road, Durham DH1 3LE, United Kingdom
*** Visiting astronomer of the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie, Heidelberg, jointly with the Spanish National Commission for Astronomy.

Send offprint requests to: B.L. Ziegler

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© European Southern Observatory (ESO) 1999

Online publication: May 6, 1999