Environment of the galaxy cluster XDCP J0044.0-2033 at z = 1.58. Secure spectroscopic cluster members are marked by solid small circles with their object ID number on top, the positions of tentative system members are indicated by small dashed circles. The logarithmically spaced contours show the spatial distribution of the X-ray emission detected with XMM-Newton. Left panel: 3′× 3′ overview image of the combined J + Ks detection band including all currently known secure and tentative cluster member galaxies. The large dashed circles indicate the 30′′ and 60′′ (≃R₅₀₀) radii about the X-ray centroid position. Right panel: color composite image centered on the X-ray centroid (white cross) made up of the Ks (red channel), J (green), and i-band (blue) with dimensions 1.6′×  1.6′.