2006A&A...459..415L

We report the discovery of Cl 2334+48, a rich cluster of galaxies in the Zone of Avoidance, identified in public images from the XMM-Newton archive. We present the main properties of this cluster using the XMM-Newton X-ray data, along with new optical spectroscopic and photometric observations. ClG J2334+4851{Cl 2334+48} is located at z=0.271±0.001, as derived from the optical spectrum of the brightest member galaxy. Such redshift agrees with a determination from the X-ray spectrum (z=0.263^+0.012_–0.010), in which an intense emission line is matched to the rest wavelength of the Fe Kα complex. Its intracluster medium has a plasma temperature of 4.92^+0.50_–0.48keV, a sub-solar abundance of 0.38±0.12Z_☉, and a bolometric luminosity of 3.2x10⁴⁴erg/s. A density contrast δ=2500 is reached in a radius of 0.5h₇₀^–1Mpc, and the corresponding enclosed mass is 1.5x10¹⁴M_☉. Optical images show an enhancement of g'-i'>2.5 galaxies around the central galaxy, as expected if these were cluster members. The central object is a luminous E-type galaxy, which is displaced ∼40h₇₀^–1kpc from the cluster X-ray centre. In addition, it has a neighbouring arc-like feature (∼22" or 90h₇₀^–1kpc from it), probably due to strong gravitational lensing. The discovery of Cl 2334+48 emphasises the remarkable capability of the XMM-Newton to reveal new clusters of galaxies in the Zone of Avoidance.