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Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/46420
Title: Planck early results. V. The Low Frequency Instrument data processing
Authors: Zacchei, A.; López-Caniego, M.; Barreiro, R. Belén; Curto, A.; Diego, J. M.; Herranz, D.; Martínez-González, Enrique; Vielva, P.
Keywords: Methods: data analysis
Cosmic background radiation
Cosmology: observations
Issue Date: Dec-2011
Publisher: EDP Sciences
Citation: Astronomy and Astrophysics 536: A5 (2011)
Abstract: We describe the processing of data from the Low Frequency Instrument (LFI) used in production of the Planck Early Release Compact Source Catalogue (ERCSC). In particular, we discuss the steps involved in reducing the data from telemetry packets to cleaned, calibrated, time-ordered data (TOD) and frequency maps. Data are continuously calibrated using the modulation of the temperature of the cosmic microwave background radiation induced by the motion of the spacecraft. Noise properties are estimated from TOD from which the sky signal has been removed using a generalized least square map-making algorithm. Measured 1/f noise knee-frequencies range from ~100 mHz at 30 GHz to a few tens of mHz at 70GHz. A destriping code (Madam) is employed to combine radiometric data and pointing information into sky maps, minimizing the variance of correlated noise. Noise covariance matrices required to compute statistical uncertainties on LFI and Planck products are also produced. Main beams are estimated down to the ≈−10dB level using Jupiter transits, which are also used for geometrical calibration of the focal plane.
Description: 19 páginas, 18 figuras, 3 tablas.-- et al.
Publisher version (URL): http://dx.doi.org/10.1051/0004-6361/201116484
URI: http://hdl.handle.net/10261/46420
ISSN: 0004-6361
DOI: 10.1051/0004-6361/201116484
E-ISSN: 1432-0746
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