The latetime integrated SachsWolfe (ISW) imprint of $R\gtrsim 100~h^{1}\, \mathrm{Mpc}$ superstructures is sourced by evolving largescale potentials due to a dominant dark energy component in the ΛCDM model. The aspect that makes the ISW effect distinctly interesting is the repeated observation of strongerthanexpected imprints from supervoids at z ≲ 0.9. Here we analyse the unprobed key redshift range 0.8 < z < 2.2 where the ISW signal is expected to fade in ΛCDM, due to a weakening dark energy component, and eventually become consistent with zero in the matter dominated epoch. On the contrary, alternative cosmological models, proposed to explain the excess lowz ISW signals, predicted a signchange in the ISW effect at z ≈ 1.5 due to the possible growth of largescale potentials that is absent in the standard model. To discriminate, we estimated the highz ΛCDM ISW signal using the Millennium XXL mock catalogue, and compared it to our measurements from about 800 supervoids identified in the eBOSS DR16 quasar catalogue. At 0.8 < z < 1.2, we found an excess ISW signal with AISW ≈ 3.6 ± 2.1 amplitude. The signal is then consistent with the ΛCDM expectation (AISW = 1) at 1.2 < z < 1.5 where the standard and alternative models predict similar amplitudes. Most interestingly, we also observed an oppositesign ISW signal at 1.5 < z < 2.2 that is in 2.7σ tension with the ΛCDM prediction. Taken at face value, these recurring hints for ISW anomalies suggest an alternative growth rate of structure in lowdensity environments at $\sim 100~h^{1}\, \mathrm{Mpc}$ scales.
more » « less NSFPAR ID:
 10405563
 Publisher / Repository:
 Oxford University Press
 Date Published:
 Journal Name:
 Monthly Notices of the Royal Astronomical Society
 Volume:
 513
 Issue:
 1
 ISSN:
 00358711
 Format(s):
 Medium: X Size: p. 1526
 Size(s):
 p. 1526
 Sponsoring Org:
 National Science Foundation
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