Sky distribution of the data. The small grey dots represent the positions of 105 783 quasars from the S11 catalogue. The small blue crosses indicate the 1218 CLASH FSRQs. Black circles mark the 33 IceCAT-1 events in the northern sky with the required positional accuracy. Circles with a red centre represent the 15 neutrinos located within our area of interest uniformly covered by the CLASH objects. A red square around a circle indicates that a CLASH FSRQ is included in the nominal error region.