Letter to the Editor

The cosmic microwave background anisotropy power spectrum measured by Archeops

¹ Centre de Recherche sur les Très Basses Températures, BP 166, 38042 Grenoble Cedex 9, France
² Cardiff University, Physics Department, PO Box 913, 5 The Parade, Cardiff, CF24 3YB, UK
³ Physique Corpusculaire et Cosmologie, Collège de France, 11 Pl. M. Berthelot, 75231 Paris Cedex 5, France
⁴ Fédération de Recherche APC, Université Paris 7, Paris, France
⁵ Laboratoire de l'Accélérateur Linéaire, BP 34, Campus Orsay, 91898 Orsay Cedex, France
⁶ CEA-CE Saclay, DAPNIA, Service de Physique des Particules, Bât. 141, 91191 Gif sur Yvette Cedex, France
⁷ Institut d'Astrophysique Spatiale, Bât. 121, Université Paris XI, 91405 Orsay Cedex, France
⁸ Centre d'Étude Spatiale des Rayonnements, BP 4346, 31028 Toulouse Cedex 4, France
⁹ California Institute of Technology, 105-24 Caltech, 1201 East California Blvd, Pasadena CA 91125, USA
¹⁰ Laboratoire d'Astrophysique de l'Obs. Midi-Pyrénées, 14 avenue E. Belin, 31400 Toulouse, France
¹¹ Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109, USA
¹² IROE–CNR, via Panciatichi, 64, 50127 Firenze, Italy
¹³ Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
¹⁴ Gruppo di Cosmologia Sperimentale, Dipart. di Fisica, Univ. “La Sapienza”, P. A. Moro, 2, 00185 Roma, Italy
¹⁵ Laboratoire d'Astrophysique, Obs. de Grenoble, BP 53, 38041 Grenoble Cedex 9, France
¹⁶ Centre de Recherche sur les Très Basses Températures, BP 166, 38042 Grenoble Cedex 9, France Cardiff University, Physics Department, PO Box 913, 5 The Parade, Cardiff, CF24 3YB, UK Physique Corpusculaire et Cosmologie, Collège de France, 11 Pl. M. Berthelot, 75231 Paris Cedex 5, France Laboratoire de l'Accélérateur Linéaire, BP 34, Campus Orsay, 91898 Orsay Cedex, France CEA-CE Saclay, DAPNIA, Service de Physique des Particules, Bât. 141, 91191 Gif sur Yvette Cedex, France Laboratoire d'Astrophysique de l'Obs. Midi-Pyrénées, 14 avenue E. Belin, 31400 Toulouse, France Institut d'Astrophysique Spatiale, Bât. 121, Université Paris XI, 91405 Orsay Cedex, France California Institute of Technology, 105-24 Caltech, 1201 East California Blvd, Pasadena CA 91125, USA Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109, USA IROE–CNR, via Panciatichi, 64, 50127 Firenze, Italy Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France Gruppo di Cosmologia Sperimentale, Dipart. di Fisica, Univ. “La Sapienza”, P. A. Moro, 2, 00185 Roma, Italy Laboratoire d'Astrophysique, Obs. de Grenoble, BP 53, 38041 Grenoble Cedex 9, France Nuclear and Astrophysics Laboratory, Keble Road, Oxford, OX1 3RH, UK CSNSM–IN2P3, Bât. 108, Campus Orsay, 91405 Orsay Cedex, France Centre d'Étude Spatiale des Rayonnements, BP 4346, 31028 Toulouse Cedex 4, France Institut des Sciences Nucléaires, 53 avenue des Martyrs, 38026 Grenoble Cedex, France Infrared Processing and Analysis Center, Caltech, 770 South Wilson Avenue, Pasadena, CA 91125, USA School of Physics and Astronomy, 116 Church St. S.E., University of Minnesota, Minneapolis MN 55455, USA Experimental Physics, National University of Ireland, Maynooth, Ireland Landau Institute for Theoretical Physics, 119334 Moscow, Russia Space Research Institute, Profsoyuznaya St. 84/32, Moscow, Russia CEA-CE Saclay, DAPNIA, Service d'Astrophysique, Bât. 709, 91191 Gif sur Yvette Cedex, France Fédération de Recherche APC, Université Paris 7, Paris, France LERMA, Observatoire de Paris, 61 Av. de l'Observatoire, 75014 Paris, France

Corresponding author: A. Benoît, benoit@grenoble.cnrs.fr

Received: 16 October 2002
Accepted: 15 December 2002

Abstract

We present a determination by the Archeops experiment of the angular power spectrum of the cosmic microwave background anisotropy in 16 bins over the multipole range . Archeops was conceived as a precursor of the Planck HFI instrument by using the same optical design and the same technology for the detectors and their cooling. Archeops is a balloon–borne instrument consisting of a 1.5 m aperture diameter telescope and an array of 21 photometers maintained at  mK that are operating in 4 frequency bands centered at 143, 217, 353 and 545 GHz. The data were taken during the Arctic night of February 7, 2002 after the instrument was launched by CNES from Esrange base (Sweden). The entire data cover ~30% of the sky. This first analysis was obtained with a small subset of the dataset using the most sensitive photometer in each CMB band (143 and 217 GHz) and 12.6% of the sky at galactic latitudes above 30 degrees where the foreground contamination is measured to be negligible. The large sky coverage and medium resolution (better than 15 arcmin) provide for the first time a high signal-to-noise ratio determination of the power spectrum over angular scales that include both the first acoustic peak and scales probed by COBE/DMR. With a binning of to 25 the error bars are dominated by sample variance for  below 200. A companion paper details the cosmological implications.