Large scale diffuse light in the Coma cluster: A multi-scale approach

¹ LAM, Traverse du Siphon, 13012 Marseille, France e-mail: christophe.adami@oamp.fr
² Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France
³ Institut d'Astrophysique de Paris, CNRS, Université Pierre et Marie Curie, 98bis Bd Arago, 75014 Paris, France
⁴ Department of Astronomy, Caltech, MS 105-24, Pasadena CA 91125, USA
⁵ Canada-France-Hawaii Telescope Corporation, 65-1238 Mamalahoa Highway, Kamuela, HI 96743
⁶ University of Wisconsin, Department of Astronomy, 475 N. Charter St., Madison, WI 53706, USA
⁷ Observatoire Midi-Pyrénées, 14 Av. Edouard Belin, 31400 Toulouse, France
⁸ NWU, Dearborn Observatory, 2131 Sheridan, 60208-2900 Evanston, USA

Received: 19 May 2004
Accepted: 23 July 2004

Abstract

We have obtained wide field images of the Coma cluster in the B, V, R and I bands with the CFH12K camera at CFHT. To search for large scale diffuse emission, we have applied to these images an iterative multiscale wavelet analysis and reconstruction technique which made it possible to model all the sources (stars and galaxies) and subtract them from the original images. We found various concentrations of diffuse emission present in the central zone around the central galaxies NGC 4874 and NGC 4889. We characterize the positions, sizes and colors of these concentrations. Some sources do not seem to have strong star formation, while one probably exhibits spiral-like colors. One possible origin for the star forming diffuse emission sources is that in the region of the two main galaxies NGC 4874 and NGC 4889 spiral galaxies have recently been disrupted and star formation is still active in the dispersed material. We also use the characteristics of the sources of diffuse emission to trace the cluster dynamics. A scenario in which the group around NGC 4874 is moving north is consistent with our data.