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

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 <sup>3

1</sup> 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

Abstract

The cluster Abell 2104 is one of the lowest redshift clusters () 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 ergs s^-1 and a high gas temperature of 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 . The gas fraction within a radius of 1.46 Mpc is %. The cluster galaxy velocity distribution has a dispersion of 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 to 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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Contents

• 1. Introduction
• 2. Optical data
  • 2.1. Observations
  • 2.2. Photometric analysis
  • 2.3. Spectroscopy
• 3. X-ray data
  • 3.1. Spectral analysis
  • 3.2. ROSAT HRI data
• 4. Analysis
  • 4.1. Mass estimate from optical data
  • 4.2. Mass estimate from X-ray data
• 5. Discussions
• 6. Conclusions and future prospects
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: December 11, 2000
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