Deep optical observations of the massive galaxy cluster Abell 1413.

Aims. We investigate the morphology and dynamics of the massive nearby galaxy cluster Abell 1413. Methods. Using wide field imaging and spectroscopic data obtained from observations at the Canada-France-Hawaii Telescope and archival SDSS data, we build a sample of more than 250 galaxies covering a region centered on the cluster and extending to its outskirts on large scales. Results. We probe the cluster morphology analyzing the projected density distribution of galaxies and find a strong variation in the ellipticity of the distribution, from 0.8 at the center of the cluster down to ~0.35 at the periphery. This may be the tracer of a prolate global mass distribution, slightly attenuated in the collisional distribution of the gas. We also study the large scale environment, identifying several structures associated to the cluster and organized along the major axis in the North-South direction. From spectroscopic data we derive the velocity dispersion and we investigate the overall dynamics of the cluster. The regular velocity dispersion supports the case for a prolate cluster aligned in the plane of the sky and embedded in a larger scale structure. [ABSTRACT FROM AUTHOR]