Letter to the Editor

Cosmological constraints from 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: 22 November 2002

Abstract

We analyze the cosmological constraints that Archeops (Benoît et al. 2003) places on adiabatic cold dark matter models with passive power-law initial fluctuations. Because its angular power spectrum has small bins in and large coverage down to COBE scales, Archeops provides a precise determination of the first acoustic peak in terms of position at multipole , height and width. An analysis of Archeops data in combination with other CMB datasets constrains the baryon content of the Universe, , compatible with Big-Bang nucleosynthesis and with a similar accuracy. Using cosmological priors obtained from recent non–CMB data leads to yet tighter constraints on the total density, e.g. using the HST determination of the Hubble constant. An excellent absolute calibration consistency is found between Archeops and other CMB experiments, as well as with the previously quoted best fit model. The spectral index n is measured to be when the optical depth to reionization, τ, is allowed to vary as a free parameter, and when τ is fixed to zero, both in good agreement with inflation.