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Astron. Astrophys. 353, 124-128 (2000)

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The X-ray morphology of the lensing galaxy cluster Cl0024+17

H. Böhringer 1, G. Soucail 2, Y. Mellier 3,4, Y. Ikebe 1 and P. Schuecker 1

1 Max-Planck-Institut für Extraterrestrische Physik, 85748 Garching, Germany
2 Observatoire Midi-Pyrénées, Laboratoire d'Astrophysique, UMR 5572, 14 Avenue E. Belin, 31400, Toulouse, France
3 Institut d'Astrophysique, 98 bis Bd. Arago, 75014 Paris, France
4 Observatoire de Paris, DEMIRM, 61 avenue de l'Observatoire, 75014 Paris, France

Received 16 August 1999 / Accepted 30 October 1999


We report the analysis of a very deep ROSAT HRI observation on one of the most interesting, distant lensing clusters, Cl0024+17. Using the X-ray surface brightness we analyse the cluster morphology and constrain the gas and gravitational mass of the cluster. We confirm the small core radius of the mass halo of [FORMULA] kpc for this cluster inferred previously from a detailed strong lensing analysis by Tyson et al. (1998) and Smail et al. (1997). Using estimated gas temperatures we find a cluster mass of about [FORMULA] [FORMULA] for a fiducial radius of [FORMULA] Mpc. This mass is lower than the mass implied by the weak lensing result of Bonnet et al. (1994) and inconsistent with a virial analysis based on the high observed galaxy velocity dispersion. The lower gravitational mass found in the present study implies, however, a gas mass fraction of the cluster e.g. at [FORMULA] Mpc radius of [FORMULA] well consistent with the general observations in rich clusters. This favours a lower mass value for the relaxed part of Cl0024+17 which could still be embedded in a larger structure achieving a consistency with the weak lensing observations.

Key words: galaxies: clusters: individual: Cl0024+17 – cosmology: dark matter – cosmology: gravitational lensing

Send offprint requests to: H. Böhringer

© European Southern Observatory (ESO) 2000

Online publication: December 8, 1999