Rocha, G. and Pagano, L. and Górski, K. M. and Huffenberger, K. M. and Lawrence, C. R. and Lange, A. E. (2010) Markov chain beam randomization: a study of the impact of PLANCK beam measurement errors on cosmological parameter estimation. Astronomy and Astrophysics, 513 . A23. ISSN 0004-6361 http://resolver.caltech.edu/CaltechAUTHORS:20100604-110642522
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We introduce a new method to propagate uncertainties in the beam shapes used to measure the cosmic microwave background to cosmological parameters determined from those measurements. The method, called markov chain beam randomization (MCBR), randomly samples from a set of templates or functions that describe the beam uncertainties. The method is much faster than direct numerical integration over systematic “nuisance” parameters, and is not restricted to simple, idealized cases as is analytic marginalization. It does not assume the data are normally distributed, and does not require Gaussian priors on the specific systematic uncertainties. We show that MCBR properly accounts for and provides the marginalized errors of the parameters. The method can be generalized and used to propagate any systematic uncertainties for which a set of templates is available. We apply the method to the Planck satellite, and consider future experiments. Beam measurement errors should have a small effect on cosmological parameters as long as the beam fitting is performed after removal of 1/f noise.
|Additional Information:||© ESO 2010. Received 31 July; Accepted 13 January 2010. G.R. is grateful to Jeffrey Jewell and Lloyd Knox for insightful discussions. L.P. acknowledges support by ASI contract I/016/07/0 “COFIS”. K.M.H. receives support from NASA via JPL subcontract 1363745. We gratefully acknowledge support by the NASA Science Mission Directorate via the US Planck Project. The research described in this paper was partially carried out at the Jet propulsion Laboratory, California Institute of Technology, under a contract with NASA.|
|Subject Keywords:||cosmic microwave background; cosmology: observations; methods: data analysis|
|Official Citation:||Markov chain beam randomization: a study of the impact of PLANCK beam measurement errors on cosmological parameter estimation G. Rocha, L. Pagano, K. M. Górski, K. M. Huffenberger, C. R. Lawrence and A. E. Lange A&A 513 A23 (2010) DOI: 10.1051/0004-6361/200913032|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||04 Jun 2010 20:18|
|Last Modified:||26 Dec 2012 12:06|
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