paper

Evidence for a high-z ISW signal from supervoids in the distribution of eBOSS quasars

arXiv:2107.13038 · doi:10.1093/mnras/stac903

Abstract

The late-time integrated Sachs-Wolfe (ISW) imprint of super-structures is sourced by evolving large-scale potentials due to a dominant dark energy component in the CDM model. The aspect that makes the ISW effect distinctly interesting is the repeated observation of stronger-than-expected imprints from supervoids at . Here we analyze the un-probed key redshift range where the ISW signal is expected to fade in CDM, 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 low- ISW signals, predicted a sign-change in the ISW effect at due to the possible growth of large-scale potentials that is absent in the standard model. To discriminate, we estimated the high- CDM 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 , we found an excess ISW signal with amplitude. The signal is then consistent with the CDM expectation () at where the standard and alternative models predict similar amplitudes. Most interestingly, we also detected an opposite-sign ISW signal at that is in tension with the CDM prediction. Taken at face value, these moderately significant detections of ISW anomalies suggest an alternative growth rate of structure in low-density environments at scales.

13 pages, 9 figures, accepted by MNRAS after minor corrections to text and some figures

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