SIMBAD references

The thermal Sunyaev-Zel'dovich (tSZ) effect is expected to provide a low scatter mass proxy for galaxy clusters since it is directly proportional to the cluster thermal energy. The tSZ observations have proven to be a powerful tool for detecting and studying them, but high angular resolution observations are now needed to push their investigation to a higher redshift. In this paper, we report high angular (20-arcsec) resolution tSZ observations of the high-redshift cluster CL J1226.9+3332 (z=0.89). It was imaged at 150 and 260GHz using the NIKA camera at the IRAM 30-m telescope. The 150GHz map shows that CL J1226.9+3332 is morphologically relaxed on large scales with evidence of a disturbed core, while the 260GHz channel is used mostly to identify point source contamination. NIKA data are combined with those of Planck and X-ray from Chandra to infer the cluster's radial pressure, density, temperature, and entropy distributions. The total mass profile of the cluster is derived, and we find M₅₀₀=5.96^+1.02_–0.79x10¹⁴M_☉ within the radius R₅₀₀=930⁺⁵⁰_–43kpc, at a 68% confidence level. (R₅₀₀ is the radius within which the average density is 500 times the critical density at the cluster's redshift.) NIKA is the prototype camera of NIKA2, a KIDs (kinetic inductance detectors) based instrument to be installed at the end of 2015. This work is, therefore, part of a pilot study aiming at optimizing tSZ NIKA2 large programs.