Millimetric observation of the SZ effect in the Corona Borealis supercluster

We have observed the Corona Borealis supercluster with the Millimeter and Infrared Testa Grigia Observatory (MITO), located in the Italian Alps, at 143, 214, 272, and 353 GHz. We present a description of the measurements, data analysis, and results of the observations together with a comparison with observations performed at 33 GHz with the Very Small Array (VSA) interferometer situated at the Teide Observatory (Tenerife, Spain). Observations have been made in the direction of the supercluster toward a cosmic microwave background (CMB) cold spot previously detected in a VSA temperature map. Observational strategy and data analysis are described in detail, explaining the procedures used to disentangle primary and secondary anisotropies in the resulting maps. From a first level of data analysis, we find evidence in MITO data of primary anisotropy but still with room for the presence of secondary anisotropy, especially when VSA results are included. With a second level of data analysis using map making and the maximum entropy method, we claim a weak detection of a faint signal compatible with a SZ effect, characterized at most by a Comptonization parameter y=(7.8+5.3-4.4)×10-6 68% CL. The low level of confidence in the presence of a SZ signal invites us to study this sky region with higher sensitivity and angular resolution experiments such as the already-planned upgraded versions of VSA and MITO.