X-ray sources overdensity around the 3C 295 galaxy cluster

Abstract We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster ( z =0.46). The logN-logS of this field is in good agreement with that computed for the Chandra Deep Field South in this work and in previous ones. Nevertheless, the logN-logS computed separately for the four ACIS-I chips reveals that there is a significant excess of sources to the North-North East and a void to the South of the central cluster. Such an asymmetric distribution is confirmed by the two-dimensional Kolmogorov-Smirnov test, which excludes ( P ∼3%) a uniform distribution. In addition, a strong spatial correlation emerges from the study of the angular correlation function of the field: the angular correlation function is above that expected for X-ray sources on a few arcmin scales. In synthesis, the present analysis may indicate a filament of the large scale structure of the Universe toward 3C 295. This kind of study may open-up a new way to map (with high efficiency) high-density peaks of large scale structures at high redshift.