2013/09/30 by Sigurd Næss, Sigurd K. Næss, Thibaut Louis
Physics and Astronomy · #Conjugate gradient method #Cosmology and Gravitation Theories #Covariance #Galaxies: Formation, Evolution, Phenomena #Maximum likelihood #Noise (video) #Preconditioner #Radio Astronomy Observations and Technology #Speedup #astro-ph.CO #astro-ph.IM
paper · pdf · doi:10.1088/1475-7516/2014/08/045
6 pages, 9 figures, accepted for publication in JCAP
arxiv created 2014/07/02 · openalex publication_date 2014/08/19 · arxiv updated 2015/06/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
High-resolution Maximum Likelihood map-making of the Cosmic Microwave Background is usually performed using Conjugate Gradients with a preconditioner that ignores noise correlations. We here present a new preconditioner that approximates the map noise covariance as circulant, and show that this results in a speedup of up to 400% for a realistic scanning pattern from the Atacama Cosmology Telescope. The improvement is especially large for polarized maps.