EDP Sciences
Free access
Issue
A&A
Volume 400, Number 3, March IV 2003
Page(s) 951 - 956
Section Stellar clusters and associations
DOI http://dx.doi.org/10.1051/0004-6361:20030087


A&A 400, 951-956 (2003)
DOI: 10.1051/0004-6361:20030087

Limits on Galactic dark matter with 5 years of EROS SMC data

C. Afonso1, 2, 3, J. N. Albert4, J. Andersen5, R. Ansari4, É. Aubourg1, P. Bareyre1, 2, J. P. Beaulieu6, G. Blanc1, X. Charlot1, F. Couchot4, C. Coutures1, R. Ferlet6, P. Fouqué7, 8, J. F. Glicenstein1, B. Goldman1, 2, 3, A. Gould1, 9, D. Graff9, M. Gros1, J. Haissinski4, C. Hamadache1, J. de Kat1, T. Lasserre1, L. Le Guillou1, É. Lesquoy1, 6, C. Loup6, C. Magneville1, J. B. Marquette6, É. Maurice10, A. Maury7, A. Milsztajn1, M. Moniez4, N. Palanque-Delabrouille1, O. Perdereau4, L. Prévot10, Y. R. Rahal4, J. Rich1, M. Spiro1, P. Tisserand1, A. Vidal-Madjar6, L. Vigroux1 and S. Zylberajch1

1  DSM/DAPNIA, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France
2  Collège de France, Physique Corpusculaire et Cosmologie, IN2P3 CNRS, 11 Pl. M. Berthelot, 75231 Paris Cedex, France
3  Department of Astronomy, New Mexico State University, Las Cruces, NM 88003-8001, USA
4  Laboratoire de l'Accélérateur Linéaire, IN2P3 CNRS, Université Paris-Sud, 91405 Orsay Cedex, France
5  Astronomical Observatory, Copenhagen University, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
6  Institut d'Astrophysique de Paris, INSU CNRS, 98bis boulevard Arago, 75014 Paris, France
7  European Southern Observatory (ESO), Casilla 19001, Santiago 19, Chile
8  Observatoire de Paris, LESIA, 92195 Meudon Cedex, France
9  Departments of Astronomy and Physics, Ohio State University, Columbus, OH 43210, USA
10  Observatoire de Marseille, 2 Pl. Le Verrier, 13248 Marseille Cedex 04, France

(Received 16 December 2002 / Accepted 17 January 2003 )

Abstract
Five years of EROS data towards the Small Magellanic Cloud have been searched for gravitational microlensing events, using a new, more accurate method to assess the impact of stellar blending on the efficiency. Four long-duration candidates have been found which, if they are microlensing events, hint at a non-halo population of lenses. Combined with results from other EROS observation programs, this analysis yields strong limits on the amount of Galactic dark matter made of compact objects. Less than 25% of a standard halo can be composed of objects with a mass between $2\times10^{-7}~M_\odot$ and 1  $M_\odot$ at the 95% C.L.


Key words: Galaxy: halo -- Galaxy: kinematics and dynamics -- Galaxy: stellar content -- cosmology: dark matter -- gravitational lensing

Offprint request: N. Palanque-Delabrouille, Nathalie.Palanque-Delabrouille@cea.fr

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© ESO 2003