The part and the whole: voids, supervoids, and their ISW imprint
  The integrated Sachs-Wolfe imprint of extreme structures in the cosmic web
probes the dynamical nature of dark energy. Looking through typical cosmic
voids, no anomalous signal has been reported. On the contrary, supervoids,
associated with large-scale fluctuations in the gravitational potential, have
shown potentially disturbing excess signals. In this study, we used the Jubilee
ISW simulation to demonstrate how the stacked signal depends on the void
definition. We found that large underdensities, with at least $\approx5$ merged
sub-voids, show a peculiar ISW imprint shape with central cold spots and
surrounding hot rings, offering a natural way to define supervoids in the
cosmic web. We then inspected the real-world BOSS DR12 data using the simulated
imprints as templates. The imprinted profile of BOSS supervoids appears to be
more compact than in simulations, requiring an extra $\alpha \approx 0.7$
re-scaling of filter sizes. The data reveals an excess ISW-like signal with
$A_{\rm ISW}\approx9$ amplitude at the $\approx2.5\sigma$ significance level,
unlike previous studies that used isolated voids and reported good consistency
with $A_{\rm ISW}=1$. The tension with the Jubilee-based $\Lambda$CDM
predictions is $\sim 2\sigma$, in consistency with independent analyses of
supervoids in Dark Energy Survey data. We show that such a very large
enhancement of the $A_{\rm ISW}$ parameter hints at a possible causal relation
between the CMB Cold Spot and the Eridanus supervoid. The origin of these
findings remains unclear.
