The significance of the integrated Sachs-Wolfe effect revisited

TL;DR

This paper revisits the integrated Sachs-Wolfe effect measurements using updated data, confirming previous results with a 4.4 sigma detection significance and addressing potential systematic errors.

Contribution

It provides an updated analysis of the ISW effect with new data, confirming previous findings and testing for systematic contamination.

Findings

ISW detection significance at 4.4 sigma

No evidence of systematic contamination

Results consistent with previous measurements

Abstract

We revisit the state of the integrated Sachs-Wolfe (ISW) effect measurements in light of newly available data and address criticisms about the measurements which have recently been raised. We update the data set previously assembled by Giannantonio et al. to include new data releases for both the cosmic microwave background (CMB) and the large-scale structure (LSS) of the Universe. We find that our updated results are consistent with previous measurements. By fitting a single template amplitude, we now obtain a combined significance of the ISW detection at the 4.4 sigma level, which fluctuates by 0.4 sigma when alternative data cuts and analysis assumptions are considered. We also make new tests for systematic contaminations of the data, focusing in particular on the issues raised by Sawangwit et al. Amongst them, we address the rotation test, which aims at checking for possible systematics by correlating pairs of randomly rotated maps. We find results consistent with the expected data covariance, no evidence for enhanced correlation on any preferred axis of rotation, and therefore no indication of any additional systematic contamination. We publicly release the results, the covariance matrix, and the sky maps used to obtain them.