1609.00301
The lensing and temperature imprints of voids on the cosmic microwave background
Cai, et al
Seared for the signature of cosmic voids in the CMB, in both the Planck temperature and lensing-convergence maps; voids should give decrements in both. Use zobov voids from DR12 SDSS CMASS sample. Base the analysis on N-body sims to avoid a posteriori bias. For the first time, detected the signature of voids in CMB lensing: the significance is 4.0 sigma, close to LCDM in both amplitude and projected density-profile shape. A temperature dip is also seen, at models significance (1.6 sigma), with amplitude about 6 times the prediction. This temperature signal is induced mostly by voids with radius between 100 and 150 Mpc/h, while the lensing signal is mostly contributed by smaller voids -- as expected; lensing relates directly to density, while ISW depends on gravitational potential. The void abundance in observations and simulations agree as well. Also repeated the analysis excluding lower-significance voids: no lensing signal is detected, with an upper limit of about 2x the LCDM prediction. But the mean temperature decrement now becomes non-zero at the 3.4 sigma level (similar to that found by Granett+) with amplitude about 20x the prediction. However, the observed dependence of temperature on void size is in poor agreement with simulations, whereas the lensing results are consistent with LCDM theory. Thus, the overall tension between theory and observations does not favor non-standard theories of gravity, despite the hints of an enhanced amplitude for the ISW effect from voids.
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