Truncation of galaxy dark matter halos in high density environments

¹ Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, Denmark e-mail: marceau@dark-cosmology.dk
² Laboratoire d'Astrophysique de Toulouse-Tarbes, CNRS-UMR 5572 & Université Paul Sabatier Toulouse III, 14 avenue Édouard Belin, 31400 Toulouse, France
³ OAMP, Laboratoire d'Astrophysique de Marseille – UMR 6110, Traverse du siphon, 13012 Marseille, France
⁴ L3AB – UMR 5804, 2 rue de l'Observatoire, BP 89, 33270 Floirac, France
⁵ Astronomy Department, Yale University, PO Box 208101, New Haven, CT 06520-8101, USA
⁶ Department of Physics, Yale University, PO Box 208101, New Haven, CT 06520-8101, USA
⁷ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
⁸ Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE, UK
⁹ Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
¹⁰ School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK

Received: 4 May 2006
Accepted: 10 October 2006

Abstract

Aims.Our aim is to constrain the properties of dark matter halos inhabiting high density environments, such as is the case in massive galaxy clusters.

Methods.We use galaxy-galaxy lensing techniques that utilize a maximum likelihood method to constrain the parameters of the lenses. It has been demonstrated that such a technique provides strong constraints on the parameters that characterize a galaxy halo, as well as on the aperture mass of these halos. In this analysis, we only use weak shear data and do not include strong lensing constraints.

Results.We present the results of a study of galaxy-galaxy lensing in a homogeneous sample of massive x-ray luminous clusters at . These have been observed in three bands with the cfh12k instrument. We find dark matter halos in these clusters to be compact compared to those inferred around isolated field galaxies of equivalent luminosity at this redshift: the half mass radius is found to be smaller than 50 kpc, with a mean total mass of order  . This is in good agreement with previous galaxy-galaxy lensing results and with numerical simulations, in particular with the tidal stripping scenario. We thus provide a strong confirmation of tidal truncation from a homogeneous sample of galaxy clusters. Moreover, it is the first time that cluster galaxies are probed successfully using galaxy-galaxy lensing techniques from ground based data.