Separation of the B component of a cosmic microwave background (CMB) polarization map from the much larger E component is an essential step in CMB polarimetry. For a map with incomplete sky coverage, this separation is necessarily hampered by the presence of ambiguous modes which could be either E or B modes. I present an efficient pixel-space algorithm for removing the ambiguous modes and separating the map into pure E and B components. The method, which works for arbitrary geometries, does not involve generating a complete basis of such modes and scales the cube of the number of pixels on the boundary of the map.

Document Type


Publication Date


Publisher Statement

Copyright © 2011 The American Physical Society. This article first appeared in Physical Review D 83, no. 8 (April 8, 2011): 083003-1-83003-13. doi:10.1103/PhysRevD.83.083003.

Please note that downloads of the article are for private/personal use only.