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A possible cold imprint of voids on the microwave background radiation

Cai, Y.-C.; Neyrinck, M.; Szapudi, I.; Cole, S.; Frenk, C.S.

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Authors

Y.-C. Cai

M. Neyrinck

I. Szapudi

C.S. Frenk



Abstract

We measure the average temperature decrement on the cosmic microwave background (CMB) produced by voids selected in the Sloan Digital Sky Survey Data Release 7 spectroscopic redshift galaxy catalog, spanning redshifts 0 < z < 0.44. We find an imprint amplitude between 2.6 and 2.9 μK as viewed through a compensated top-hat filter scaled to the radius of each void, we assess the statistical significance of the imprint at ~2σ, and we make crucial use of N-body simulations to calibrate our analysis. As expected, we find that large voids produce cold spots on the CMB through the integrated Sachs-Wolfe (ISW) effect. However, we also find that small voids in the halo density field produce hot spots, because they reside in contracting, larger-scale overdense regions. This is an important effect to consider when stacking CMB imprints from voids of different radii. We have found that the same filter radius that gives the largest ISW signal in simulations also yields close to the largest detected signal in the observations. However, although it is low in significance, our measured signal has a much higher amplitude than expected from ISW in the concordance ΛCDM universe. The discrepancy is also at the ~2σ level. We have demonstrated that our result is robust against the varying of thresholds over a wide range.

Citation

Cai, Y., Neyrinck, M., Szapudi, I., Cole, S., & Frenk, C. (2014). A possible cold imprint of voids on the microwave background radiation. Astrophysical Journal, 786(2), Article 110. https://doi.org/10.1088/0004-637x/786/2/110

Journal Article Type Article
Publication Date May 10, 2014
Deposit Date May 14, 2014
Publicly Available Date May 20, 2014
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 786
Issue 2
Article Number 110
DOI https://doi.org/10.1088/0004-637x/786/2/110
Keywords Cosmic background radiation, Cosmology: observations, Large-scale structure of universe, Methods: statistical.

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Copyright Statement
© 2014. The American Astronomical Society. All rights reserved. Printed in the U.S.A.







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