EDP Sciences
Free access
Volume 421, Number 2, July II 2004
Page(s) 583 - 593
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20035925

A&A 421, 583-593 (2004)
DOI: 10.1051/0004-6361:20035925

Collisionless evaporation from cluster elliptical galaxies

A contributor to the intracluster stellar population
V. Muccione1 and L. Ciotti2

1  Observatoire de Genève, chemin des Maillettes 51, 1290 Sauverny, Suisse
2  Dipartimento di Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy
    e-mail: luca.ciotti@unibo.it

(Received 22 December 2003 / Accepted 3 April 2004 )

By means of simple numerical models we discuss whether collisionless stellar evaporation from cluster elliptical galaxies could be an effective mechanism for the production of intracluster stellar populations. The effectiveness of this mechanism is due to the fact that, for realistic galaxy and cluster models, the galaxy oscillation periods near equilibrium configurations in the cluster tidal field are of the same order of stellar orbital times in the external parts of the galaxies themselves. With the aid of Monte-Carlo simulations we explore the evolution of stellar orbits in oscillating galaxies placed near different equilibrium positions. We found that, over an Hubble time, the main effect is a substantial expansion of the galactic outskirts, particularly affecting the galaxy at the cluster center and those orbiting near the cluster core radius: overall, approximately the 10% of the galaxy mass is affected. Thus, the proposed mechanism could be of some importance in the shaping of the halo of cD galaxies and in making easier "galaxy harassment" in the formation of the intracluster stellar population.

Key words: galaxies: elliptical and lenticular, cD -- Galaxy: evolution -- galaxies: interactions -- galaxies: kinematics and dynamics

Offprint request: V. Muccione, veruska.muccione@obs.unige.ch

© ESO 2004