Issue |
A&A
Volume 404, Number 1, June II 2003
|
|
---|---|---|
Page(s) | 145 - 156 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20030307 | |
Published online | 26 May 2003 |
Bulge microlensing optical depth from EROS 2 observations *
1
CEA, DSM, DAPNIA, Centre d'Études de 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 de Paris-Sud, 91405 Orsay Cedex, France
5
DASGAL, INSU-CNRS, 77 avenue de l'Observatoire, 75014 Paris, France
6
Astronomical Observatory, Copenhagen University, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
7
Institut d'Astrophysique de Paris, INSU CNRS, 98bis boulevard Arago, 75014 Paris, France
8
Universidad de la Serena, Facultad de Ciencias, Departamento de Fisica, Casilla 554, La Serena, Chile
9
Observatoire de Paris, LESIA, 92195 Meudon Cedex, France
10
European Southern Observatory (ESO), Casilla 19001, Santiago 19, Chile
11
Department of Astronomy, Ohio State University, Columbus, OH 43210, USA
12
Observatoire de Marseille, 2 Pl. Le Verrier, 13248 Marseille Cedex 04, France
Corresponding author: C. Afonso, afonso@hep.saclay.cea.fr
Received:
22
August
2002
Accepted:
28
February
2003
We present a measurement of the microlensing optical depth toward the Galactic bulge based on the analysis of 15 contiguous fields centered on and containing clump-giant stars (belonging to the extended clump area) monitored during almost three bulge seasons by EROS (Expérience de Recherche d'Objets Sombres). We find averaged over all fields, based on 16 microlensing events with clump giants as sources. This value is substantially below several other determinations by the MACHO and OGLE groups and is more in agreement with what is expected from axisymmetric and non-axisymmetric bulge models.
Key words: Galaxy: stellar content / Galaxy: structure / gravitational lensing
© ESO, 2003
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