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Astron. Astrophys. 355, L39-L42 (2000)
Letter to the Editor
Not enough stellar mass Machos in the Galactic halo *
T. Lasserre 1,
C. Afonso 1,
J.N. Albert 2,
J. Andersen 6,
R. Ansari 2,
É. Aubourg 1,
P. Bareyre 1,4,
F. Bauer 1,
J.P. Beaulieu 3,
G. Blanc 1,
A. Bouquet 4,
S. Char
7,
X. Charlot 1,
F. Couchot 2,
C. Coutures 1,
F. Derue 2,
R. Ferlet 3,
J.F. Glicenstein 1,
B. Goldman 1,
A. Gould ** 8,1,
D. Graff 8,1,
M. Gros 1,
J. Ha"
ssinski 2,
J.C. Hamilton 4,
D. Hardin 1,
J. de Kat 1,
A. Kim 4,
É. Lesquoy 1,3,
C. Loup 3,
C. Magneville 1,
B. Mansoux 2,
J.B. Marquette 3,
É. Maurice 5,
A. Milsztajn 1,
M. Moniez 2,
N. Palanque-Delabrouille 1,
O. Perdereau 2,
L. Prévot 5,
N. Regnault 2,
J. Rich 1,
M. Spiro 1,
A. Vidal-Madjar 3,
L. Vigroux 1 and
S. Zylberajch
The EROS collaboration 1
1 CEA, DSM, DAPNIA, Centre d'Études de Saclay, 91191 Gif-sur-Yvette Cedex, France
2 Université de Paris-Sud, Laboratoire de l'Accélérateur Linéaire, IN2P3 CNRS, 91405 Orsay Cedex, France
3 Institut d'Astrophysique de Paris, INSU CNRS, 98 bis Boulevard Arago, 75014 Paris, France
4 Collège de France, Physique Corpusculaire et Cosmologie, IN2P3 CNRS, 11 pl. M. Berthelot, 75231 Paris Cedex, France
5 Observatoire de Marseille, 2 pl. Le Verrier, 13248 Marseille Cedex 04, France
6 Copenhagen University, Astronomical Observatory, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
7 Universidad de la Serena, Facultad de Ciencias, Departamento de Fisica, Casilla 554, La Serena, Chile
8 Ohio State University, Departments of Astronomy and Physics, Columbus, OH 43210, U.S.A.
Received 11 February 2000 / Accepted 23 February 2000
Abstract
We combine new results from the search for microlensing towards the
Large Magellanic Cloud (LMC ) by EROS 2
(Expérience de Recherche d'Objets Sombres) with limits
previously reported by EROS 1 and EROS 2
towards both Magellanic Clouds. The derived upper limit on the
abundance of stellar mass MACHO s rules out such
objects as an important component of the Galactic halo if their mass
is smaller than ![[FORMULA]](img1.gif)
.
Key words: Galaxy:
halo 
Galaxy: kinematics and
dynamics
Galaxy: stellar
content
galaxies: Magellanic
Clouds
cosmology: dark
matter
cosmology: gravitational lensing
* Based on observations made at the European Southern Observatory, La Silla, Chile.
** Alfred P. Sloan Foundation Fellow
Send offprint requests to: Thierry.Lasserre@cea.fr
Contents
- 1. Research context
- 2. Experimental setup and LMC observations
- 3. LMC data analysis
- 4. EROS1 results revisited
- 5. Limits on Galactic halo Machos
- 6. Discussion and conclusion
- Acknowledgements
- References
© European Southern Observatory (ESO) 2000
Online publication: March 21, 2000
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