Off-line radiometric analysis of Planck-LFI data

Abstract

The Planck Low Frequency Instrument (LFI) is an array of22 pseudo-correlation radiometers on-board the Planck satellite tomeasure temperature and polarization anisotropies in the CosmicMicrowave Background (CMB) in three frequency bands (30, 44 and70 GHz).To calibrate and verify the performances of the LFI, a software suitenamed LIFE has been developed. Its aims are to provide a commonplatform to use for analyzing the results of the tests performed onthe single components of the instrument (RCAs, Radiometric ChainAssemblies) and on the integrated Radiometric Array Assembly(RAA). Moreover, its analysis tools are designed to be used during theflight as well to produce periodic reports on the status of theinstrument.The LIFE suite has been developed using a multi-layered,cross-platform approach. It implements a number of analysis moduleswritten in RSI IDL, each accessing the data through a portable andheavily optimized library of functions written in C and C++. One ofthe most important features of LIFE is its ability to run the samedata analysis codes both using ground test data and real flight dataas input.The LIFE software suite has been successfully used during the RCA/RAAtests and the Planck Integrated System Tests. Moreover, thesoftware has also passed the verification for its in-flight use duringthe System Operations Verification Tests, held in October 2008.