EDP Sciences
Free access
Volume 382, Number 3, February II 2002
Page(s) 1138 - 1150
Section Instruments, observational techniques and data processing
DOI http://dx.doi.org/10.1051/0004-6361:20011681

A&A 382, 1138-1150 (2002)
DOI: 10.1051/0004-6361:20011681

Non-circular rotating beams and CMB experiments

J. V. Arnau1, A. M. Aliaga2 and D. Sáez2

1  Departamento de Matemática Aplicada, Universidad de Valencia, 46100 Burjassot, Valencia, Spain
    e-mail: jose.arnau@uv.es
2  Departamento de Astronomía y Astrofísica, Universidad de Valencia, 46100 Burjassot, Valencia, Spain

(Received 10 August 2001 / Accepted 22 November 2001 )

This paper is concerned with small angular scale experiments for the observation of cosmic microwave background anisotropies. In the absence of beam, the effects of partial coverage and pixelisation are disentangled and analyzed (using simulations). Then, appropriate maps involving the CMB signal plus the synchrotron and dust emissions from the Milky Way are simulated, and an asymmetric beam - which turns following different strategies - is used to smooth the simulated maps. An associated circular beam is defined to estimate the deviations in the angular power spectrum produced by beam asymmetry without rotation and, afterwards, the deviations due to beam rotation are calculated. For a certain large coverage, the deviations due to pure asymmetry and asymmetry plus rotation appear to be very systematic (very similar in each simulation). Possible applications of the main results of this paper to data analysis in large coverage experiments - as PLANCK - are outlined.

Key words: cosmology: cosmic microwave background -- cosmology: theory -- large-scale structure of the universe  -- methods: numerical -- methods: data analysis

Offprint request: D. Sáez, diego.saez@uv.es

© ESO 2002