2018/10/20 by Vipin Sudevan, Sudevan, Vipin, Rajib Saha +1
Earth and Planetary Sciences · Mathematics · Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Geophysics and Gravity Measurements #Statistical and numerical algorithms
paper · pdf · doi:10.48550/arxiv.1810.08872
openalex publication_date 2018/10/20 · openalex created_date 2022/08/02 · openalex updated_date 2026/07/28
In this work, we formalize a new technique to investigate joint posterior\ndensity of Cosmic Microwave Background (CMB) signal and its theoretical angular\npower spectrum given the observed data, using the global\ninternal-linear-combination (ILC) method first proposed by Sudevan & Saha\n(2017). We implement the method on low resolution CMB maps observed by WMAP and\nPlanck satellite missions, using Gibbs sampling, assuming that the detector\nnoise is negligible on large angular scales of the sky. The main products of\nour analysis are best fit CMB cleaned map and its theoretical angular power\nspectrum along with their error estimates. We validate the methodology by\nperforming Monte Carlo simulations that includes realistic foreground models\nand noise levels consistent with WMAP and Planck observations. Our method has\nan unique advantage that the posterior density is obtained without any need to\nexplicitly model foreground components. Secondly, the power spectrum results\nwith the error estimates can be directly used for cosmological parameter\nestimations.\n