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Astron. Astrophys. 363, 440-450 (2000)

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Probing the gravitational potential of a nearby lensing cluster Abell 2104

H. Liang 1, L. Lémonon 2, I. Valtchanov 2, M. Pierre 2 and G. Soucail 3

1 University of Bristol, Department of Physics, Tyndall Avenue, Bristol BS8 1TL, UK (h.liang@bristol.ac.uk)
2 CEA Saclay DSM/DAPNIA/SAp, Service d'Astrophysique, 91191 Gif sur Yvette, France
3 Observatoire Midi Pyrénées, Laboratoire d'Astrophysique de Toulouse, URA 285, 14 Avenue E. Belin, 31400 Toulouse, France

Received 3 May 1999 / Accepted 12 October 2000


The cluster Abell 2104 is one of the lowest redshift clusters ([FORMULA]) known to have a gravitational lensing arc. We present detailed analysis of the cluster properties such as the gravitational potential using the X-ray data from ROSAT (HRI) and ASCA , as well as optical imaging and spectroscopic data from the CFHT. The cluster is highly luminous in the X-ray with a bolometric luminosity of [FORMULA] ergs s-1 and a high gas temperature of [FORMULA] keV. The X-ray emission extending out to at least a radius of 1.46 Mpc, displays significant substructure. The total mass deduced from the X-ray data under the assumption of hydrostatic equilibrium and isothermal gas, is found to be [FORMULA]. The gas fraction within a radius of 1.46 Mpc is [FORMULA]%. The cluster galaxy velocity distribution has a dispersion of [FORMULA] km s-1 with no obvious evidence for substructure. The total mass within 1.46 Mpc, deduced from Jean's equation using the observed galaxy number density distribution and velocity dispersion, is found to be [FORMULA] to [FORMULA] marginally consistent with the X-ray deduced total mass.

Key words: galaxies: clusters: general – galaxies: clusters: individual: A 2104 – cosmology: dark matter – cosmology: gravitational lensing

Send offprint requests to: H. Liang

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© European Southern Observatory (ESO) 2000

Online publication: December 11, 2000