Clustering of local extrema in Planck CMB maps
Mar 16, 202015 pages
Published in:
- Mon.Not.Roy.Astron.Soc. 503 (2021) 1, 815-829
- Published: Mar 25, 2021
e-Print:
- 2003.07364 [astro-ph.CO]
View in:
Citations per year
Abstract: (Oxford University Press)
The clustering of local extrema will be exploited to examine Gaussianity, asymmetry, and the footprint of the cosmic-string network on the CMB observed by Planck. The number density of local extrema (n_pk for peak and n_tr for trough) and sharp clipping (n_pix) statistics support the Gaussianity hypothesis for all component separations. However, the pixel at the threshold reveals a more consistent treatment with respect to end-to-end simulations. A very tiny deviation from associated simulations in the context of trough density, in the threshold range ϑ ∈ [−2–0] for NILC and CR component separations, are detected. The unweighted two-point correlation function, Ψ, of the local extrema illustrates good consistency between different component separations and corresponding Gaussian simulations for almost all available thresholds. However, for high thresholds, a small deficit in the clustering of peaks is observed with respect to the Planck fiducial ΛCDM model. To put a significant constraint on the amplitude of the mass function based on the value of Ψ around the Doppler peak (θ ≈ 70–75 arcmin), we should consider ϑ ≲ 0.0. The scale-independent bias factors for the peak above a threshold for large separation angle and high threshold level are in agreement with the value expected for a pure Gaussian CMB. Applying the n_pk, n_tr, Ψ_pk − pk and Ψ_tr − tr measures on the tessellated CMB map with patches of 7.5^2 deg^2 size prove statistical isotropy in the Planck maps. The peak clustering analysis puts the upper bound on the cosmic-string tension, Gμ^(up) ≲ 5.59 × 10^−7, in SMICA.Note:
- 17 pages, 7 figures, and 3 tables. Including major revision and matched to the accepted version that appeared in MNRAS
- methods: data analysis
- methods: numerical
- methods: statistical
- cosmic microwave background
- theory
- early Universe
References(157)
Figures(19)