A possible common explanation for several cosmic microwave background (CMB) anomalies: A strong impact of nearby galaxies on observed large-scale CMB fluctuations

Abstract

In Luparello et al. 2023, a new and hitherto unknown CMB foreground was detected. A systematic decrease in Cosmic Microwave Background (CMB) temperatures around nearby large spiral galaxies points to an unknown interaction with CMB photons in a sphere up to several projected Mpc around these galaxies. We investigate to which extent this foreground may impact the CMB fluctuations map and create the so-called CMB anomalies. Using the observed temperature decrements around the galaxies, and making some general assumptions about the unknown interaction, we propose a common radial temperature profile. By assigning this profile to nearby galaxies in the redshift range $z=[0.004,0.02]$ we create a foreground map model. We find a remarkable resemblance between this temperature model map based on nearby galaxies and the Planck CMB map. Out of 1000 simulated maps, none of them show such a strong correlation with the foreground map over both large and small angular scales. In particular, the quadrupole, octopole, as well as $\ell =4$ and $\ell =5$ modes correlate with the foreground map to high significance. Furthermore, one of the most prominent temperature decrements in the foreground map coincides with the position of the CMB cold spot. The largest scales of the CMB and thereby the cosmological parameters, may have important changes after proper corrections of this foreground component. However, a reliable corrected CMB map can only be derived when suitable physical mechanisms are proposed and tested.

5 pages, 4 figures, revised version which is accepted for publication in A&A Letters

References in corpus (4)

• Cosmic Microwave Background Quadrupole and Ellipsoidal Universe
• The DES view of the Eridanus supervoid and the CMB Cold Spot
• The size of our causal Universe
• Unexpected Topology of the Temperature Fluctuations in the Cosmic Microwave Background

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• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Measuring the reionization optical depth without large-scale CMB polarization
• The CMB Cold Spot as predicted by foregrounds around nearby galaxies
• Hemispherical Power Asymmetry in intensity and polarization for Planck PR4 data
• Revisiting the large-scale CMB anomalies: The impact of the SZ signal from the Local Universe
• A p<0.0001 detection of CMB cooling in galactic halos and its possible relation to dark matter
• The anomaly of the CMB power with the latest Planck data
• Unexplained correlation between the Cosmic Microwave Background temperature and the local matter density distribution
• Homology reveals significant anisotropy in the cosmic microwave background
• Far-infrared to centimeter emission of very nearby galaxies with archival data
• Linear perturbations of an exact gravitational wave in the Bianchi IV universe
• Revisiting the CMB homogeneity scale: low multipoles removal effect and extragalactic foreground masking