Non-circular beam correction to the CMB power spectrum

被引:8
|
作者
Souradeep, Tarun
Mitra, Sanjit
Sengupta, Anand
Ray, Subharthi
Saha, Rajib
机构
[1] Inter Univ Ctr Astron & Astrophys, Pune 411007, Maharashtra, India
[2] Sch Phys & Astron, Cardiff CF24 3YB, Wales
[3] Indian Inst Technol, Dept Phys, Kanpur 208016, Uttar Pradesh, India
关键词
cosmology; cosmic microwave background; theory; observations;
D O I
10.1016/j.newar.2006.09.011
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
In the era of high precision CMB measurements, systematic effects are beginning to limit the ability to extract subtler cosmological information. The non-circularity of the experimental beam has become progressively important as CMB experiments strive to attain higher angular resolution and sensitivity. The effect of non-circular beam on the power spectrum is important at multipoles larger than the beam-width. For recent experiments with high angular resolution, optimal methods of power spectrum estimation are computationally prohibitive and sub-optimal approaches, such as the Pseudo-C, method are used. We provide an analytic framework for correcting the power spectrum for the effect of beam non-circularity and non-uniform sky coverage (including incomplete/masked sky maps). The approach is perturbative in the distortion of the beam from non-circularity allowing for rapid computations when the beam is mildly non-circular. We advocate that when the non-circular beams are important, it is computationally advantageous to employ 'soft' azimuthally apodized masks whose spherical harmonic transforms die down fast with m. (c) 2006 Elsevier B.V. All rights reserved.
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收藏
页码:1030 / 1035
页数:6
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