Optimized in-flight absolute calibration for extended CMB surveys

Abstract

Accurate measurements of the Cosmic Microwave Background (CMB) anisotropy call for high precision and reliability of the in-flight calibration. For extended surveys the CMB dipole provides an excellent calibration source at frequencies lower than 200 GHz; however poorly known foreground emissions, such as diffuse galactic components, complicate the signal and introduce a systematic error in the calibration. We show that introducing a weight function that takes into account the uncertainty in the a priori knowledge of the sky, allows us to substantially improve the calibration accuracy with respect to methods involving galactic latitude cuts. This new method is tested for Planck-LFI radiometers at 30 and 100 GHz. On short time scales (less than 1 day) the absolute calibration of each channel can be recovered with an overall 1-2% accuracy. We also consider the effect of CMB anisotropy itself on the calibration, and find that knowledge of the CMB pattern on large scales is needed to keep the short-time scale calibration accuracy within 1%

11 pages, 15 figures, accepted to Astronomy & Astrophysics

References in corpus (13)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• A Flat Universe from High-Resolution Maps of the Cosmic Microwave Background Radiation
• The Cosmic Microwave Background Spectrum from the Full COBE/FIRAS Data Set
• MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on angular scales of 10 arcminutes to 5 degrees
• DASI First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum
• Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS
• Diffuse Galactic Emission from Spinning Dust Grains
• The Anisotropy of the Microwave Background to l = 3500: Mosaic Observations with the Cosmic Background Imager
• The Cosmic Microwave Background Anisotropy Power Spectrum measured by Archeops
• A radio catalog of Galactic HII regions for applications from decimeter to millimeter wavelengths
• The Planck-LFI instrument: analysis of the 1/f noise and implications for the scanning strategy
• Cosmic Background dipole measurements with Planck-High Frequency Instrument
• SUB--DEGREE ANISOTROPY OBSERVATIONS: GROUND--BASED, BALLOON--BORNE AND SPACE EXPERIMENTS

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• Archeops In-flight Performance, Data Processing and Map Making
• Planck-LFI radiometers' spectral response
• Effects of CMB temperature uncertainties on cosmological parameter estimation
• The linearity response of the Planck-LFI flight model receivers
• On the dipole straylight contamination in spinning space missions dedicated to CMB anisotropy
• On the Transits of Solar System Objects in the Forthcoming PLANCK Mission: Data Flagging and Coeval Multifrequency Observations