ISW in $\Lambda$CDM or something else?
  We investigate a correlation between the Planck's CMB temperature map and
statistics based on the space density of quasars in the SDSS catalogue. It is
shown that the amplitude of the positive correlation imposes a lower limit on
the amplitude of the Integrated Sachs-Wolfe (ISW) effect independent of the
quasar bias factor. Implications of this constraint for the ISW effect in the
LambdaCDM model are examined. Strength of the correlation indicates that the
rms of temperature fluctuations associated with the quasars distributed between
1500 and 3000 Mpc likely exceeds 11-12 {\mu}K. The signal seems to be related
to an overall space distribution of quasars rather than to a few exceptionally
dominant structures like supervoids. Although, the present estimates are
subject to sizable uncertainties, the signal apparently exceeds the model
predictions of the ISW effect for the standard LambdaCDM cosmology. This
conclusion is consistent with several other investigations that also claim some
disparity between the observed ISW signal and the theoretical predictions.
