First observation of the thermal Sunyaev-Zel'dovich effect with kinetic
  inductance detectors
  Clusters of galaxies provide valuable information on the evolution of the
Universe and large scale structures. Recent cluster observations via the
thermal Sunyaev-Zel'dovich (tSZ) effect have proven to be a powerful tool to
detect and study them. In this context, high resolution tSZ observations (~
tens of arcsec) are of particular interest to probe intermediate and high
redshift clusters. Observations of the tSZ effect will be carried out with the
millimeter dual-band NIKA2 camera, based on Kinetic Inductance Detectors (KIDs)
to be installed at the IRAM 30-meter telescope in 2015. To demonstrate the
potential of such an instrument, we present tSZ observations with the NIKA
camera prototype, consisting of two arrays of 132 and 224 detectors that
observe at 140 and 240 GHz with a 18.5 and 12.5 arcsec angular resolution,
respectively. The cluster RX J1347.5-1145 was observed simultaneously at 140
and 240 GHz. We used a spectral decorrelation technique to remove the
atmospheric noise and obtain a map of the cluster at 140 GHz. The efficiency of
this procedure has been characterized through realistic simulations of the
observations. The observed 140 GHz map presents a decrement at the cluster
position consistent with the tSZ nature of the signal. We used this map to
study the pressure distribution of the cluster by fitting a gNFW model to the
data. Subtracting this model from the map, we confirm that RX J1347.5-1145 is
an ongoing merger, which confirms and complements previous tSZ and X-ray
observations. For the first time, we demonstrate the tSZ capability of KID
based instruments. The NIKA2 camera with ~ 5000 detectors and a 6.5 arcmin
field of view will be well-suited for in-depth studies of the intra cluster
medium in intermediate to high redshifts, which enables the characterization of
recently detected clusters by the Planck satellite.
