A weak lensing study of the Coma clusterR. Gavazzi1, C. Adami2, F. Durret1, J.-C. Cuillandre3, O. Ilbert2, A. Mazure2, R. Pelló4, and M. P. Ulmer5
1 Institut d'Astrophysique de Paris, CNRS UMR 7095 & Univ. Paris 6, 98bis Bd Arago, 75014 Paris, France
2 LAM, OAMP, Université Aix-Marseille & CNRS, 38 rue Frédéric Joliot-Curie, 13388 Marseille 13 Cedex, France
3 Canada-France-Hawaii Telescope Corporation, Kamuela, HI 96743, USA
4 Laboratoire d'Astrophysique de Toulouse-Tarbes, Université de Toulouse, CNRS, 14 Av. Edouard Belin, 31400 Toulouse, France
5 Department Physics & Astronomy, Northwestern University, Evanston, IL 60208-2900, USA
Received 12 February 2009 / Accepted 28 March 2009
Context. Due to observational constraints, dark matter determinations in nearby clusters based on weak lensing are still extremely rare, in spite of their importance for the determination of cluster properties independent of other methods.
Aims. We present a weak lensing study of the Coma cluster (redshift ~0.024) based on deep images obtained at the CFHT.
Methods. After obtaining photometric redshifts for the galaxies in our field based on deep images in the u* (1 1 deg2), and in the B, V, R and I bands (42' 52'), allowing us to eliminate foreground galaxies, we apply weak lensing calculations on shape measurements performed in the u* image.
Results. We derive a map of the mass distribution in Coma, as well as the radial shear profile, and the mass and concentration parameter at various radii. We obtain and , in good agreement with previous measurements.
Conclusions. With deep wide field images it is now possible to analyze nearby clusters with weak lensing techniques, thus opening a broad new field of investigation.
Key words: gravitational lensing -- galaxies: clusters: individual: Coma
© ESO 2009