CMB anomalies after Planck
By D. Schwarz, C. Copi, D. Huterer, Glenn Starkman. 2015
334 citations recorded by the source corpus.
Several unexpected features have been observed in the microwave sky at large angular scales, both by WMAP and by Planck. Among those features is a lack of both variance and correlation on the largest angular scales, alignment of the lowest multipole moments with one another and with the motion and geometry of the solar system, a hemispherical power asymmetry or dipolar power modulation, a preference for odd parity modes and an unexpectedly large cold spot in the Southern hemisphere. The individual p-values of the significance of these features are in the per mille to per cent level, when compared to the expectations of the best-fit inflationary ΛCDM model. Some pairs of those features are demonstrably uncorrelated, increasing their combined statistical significance and indicating a significant detection of CMB features at angular scales larger than a few degrees on top of the standard model. Despite numerous detailed investigations, we still lack a clear understanding of these large-scale features, which seem to imply a violation of statistical isotropy and scale invariance of inflationary perturbations. In this contribution we present a critical analysis of our current understanding and discuss several ideas of how to make further progress.
Subfields: Astronomy and Astrophysics, Statistical and Nonlinear Physics
View Paper: https://www.semanticscholar.org/paper/2f0beb68749d3cbc6c55dffa7ef74ab1ae3df639
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Citations in the corpus
- Probing cosmic isotropy with a new X-ray galaxy cluster sample through the LX–T scaling relation (2020, background): “…and the unexpected quadrupole-octopole alignment and the existence of the Cold Spot at (l, b) = (210◦,−57◦) (Tegmark et al. 2003; Vielva et al. 2004; Kim & Naselsky 2010; Aluri & Jain 2012; Cai et al. 2014; Planck Collaboration XXIII 2014; Planck Collaboration XVI 2016; Schwarz et al. 2016).”
- A Test of the Cosmological Principle with Quasars (2020, background): “…the concomitant effects on higher multipoles of the CMB anisotropy (Challinor & van Leeuwen 2002); however, even the precise measurements of these by Planck allow up to 40% of the observed dipole to be due to effects other than the Solar System’s motion (see discussion in Schwarz et al. 2016).”
- Evidence for anisotropy of cosmic acceleration (2018, methodology): “The code used here is available at: https://github.com/ rameez3333/Dipole_JLA perturbations; nevertheless there is no consensus yet on either their physical nature or their origin (Schwarz et al. 2016).”