ArtDeco: a beam-deconvolution code for absolute cosmic microwave background measurements^⋆

¹ University of HelsinkiDepartment of Physics, PO Box 64 00014, Helsinki Finland
e-mail: elina.keihanen@helsinki.fi
² Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany
e-mail: martin@mpa-garching.mpg.de

Received: 7 August 2012
Accepted: 10 October 2012

Abstract

We present a method for beam-deconvolving cosmic microwave background (CMB) anisotropy measurements. The code takes as input the time-ordered data along with the corresponding detector pointings and known beam shapes, and produces as output the harmonic a_Tlm, a_Elm, and a_Blm coefficients of the observed sky. From these one can derive temperature and Q and U polarisation maps. The method is applicable to absolute CMB measurements with wide sky coverage, and is independent of the scanning strategy. We tested the code with extensive simulations, mimicking the resolution and data volume of Planck 30 GHz and 70 GHz channels, but with exaggerated beam asymmetry. We applied it to multipoles up to l = 1700 and examined the results in both pixel space and harmonic space. We also tested the method in presence of white noise.