Testing Gaussianity on Archeops data

¹ Instituto de Física de Cantabria, CSIC-Universidad de Cantabria, Avda. de los Castros s/n, 39005 Santander, Spain
² Dpto. de Física Moderna, Universidad de Cantabria, Avda. los Castros s/n, 39005 Santander, Spain
³ Laboratoire de Physique Subatomique et de Cosmologie, 53 avenue des Martyrs, 38026 Grenoble Cedex, France
⁴ Laboratoire d'Astrophysique, Obs. de Grenoble, BP 53, 38041 Grenoble Cedex 9, France e-mail: reprints@archeops.org

Received: 5 December 2006
Accepted: 16 July 2007

Abstract

Aims.We performed a Gaussianity analysis using a goodness-of-fit test and the Minkowski functionals on the sphere to study the measured Archeops Cosmic Microwave Background (CMB) temperature anisotropy data for a 143 GHz Archeops bolometer. We consider large angular scales, greater than 1.8 degrees, and a large fraction of the North Galactic hemisphere, around 16%, with a galactic latitude degrees.

Methods. The considered goodness-of-fit test, first proposed by Rayner & Best (1989, Smooth Tests of Goodness of Fit), was applied to the data after a signal-to-noise decomposition. The three Minkowski functionals on the sphere were used to construct a statistic using different thresholds. The former method was calibrated using simulations of Archeops data containing the CMB signal and instrumental noise in order to check its asymptotic convergence. Two kind of maps produced with two different map-making techniques (coaddition and Mirage) are analysed.

Results. Archeops maps for both Mirage and coaddition map-making, are compatible with Gaussianity. From these results we can exclude a dust and atmospheric contamination larger than 7.8% (90% CL). Also the non-linear coupling parameter f_nl can be constrained to be at the 95% CL and on angular scales of 1.8 degrees. For comparison, the same method was applied to data from the NASA WMAP satellite in the same region of sky. The 1-year and 3-year releases were used. Results are compatible with those obtained with Archeops, implying in particular an upper limit for f_nl on degree angular scales.