Volume 454, Number 1, July IV 2006
|Page(s)||185 - 199|
|Section||Galactic structure, stellar clusters, and populations|
|Published online||03 July 2006|
Galactic Bulge microlensing optical depth from EROS-2
CEA, DSM, DAPNIA, Centre d'Études de Saclay, 91191 Gif-sur-Yvette Cedex, France
2 Laboratoire de l'Accélérateur Linéaire, IN2P3 CNRS, Université de Paris-Sud, 91405 Orsay Cedex, France
3 The Niels Bohr Institute, Copenhagen University, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
4 Institut d'Astrophysique de Paris, UMR 7095 CNRS, Université Pierre & Marie Curie, 98bis boulevard Arago, 75014 Paris, France
5 Observatoire Midi-Pyrénées, Laboratoire d'Astrophysique (UMR 5572), 14 Av. E. Belin, 31400 Toulouse, France
6 European Southern Observatory (ESO), Casilla 19001, Santiago 19, Chile
7 Department of Astronomy, Ohio State University, Columbus, OH 43210, USA
8 Observatoire de Marseille, 2 place Le Verrier, 13248 Marseille Cedex 04, France
Accepted: 10 April 2006
Aims.We present a new EROS-2 measurement of the microlensing optical depth toward the Galactic Bulge.
Methods.Light curves of clump-giant stars distributed over of the Bulge were monitored during seven Bulge seasons. 120 events were found with apparent amplifications greater than 1.6 and Einstein radius crossing times in the range . This is the largest existing sample of clump-giant events and the first to include northern Galactic fields.
Results.In the Galactic latitude range , we find with . These results are in good agreement with our previous measurement, with recent measurements of the MACHO and OGLE-II groups, and with predictions of Bulge models.
Key words: Galaxy: bulge / Galaxy: stellar contents / Galaxy: structure / gravitational lensing
© ESO, 2006
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