Pressure distribution of the high-redshift cluster of galaxies CL
  J1226.9+3332 with NIKA
  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 260
GHz using the NIKA camera at the IRAM 30-meter telescope. The 150 GHz map shows
that CL J1226.9+3332 is morphologically relaxed on large scales with evidence
of a disturbed core, while the 260 GHz 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 $M_{500} = 5.96^{+1.02}_{-0.79} $ x $10^{14} M_{\odot}$ within the radius
$R_{500} = 930^{+50}_{-43}$ kpc, at a 68% confidence level. ($R_{500}$ 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.
