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Observation of Microlensing towards the Galactic Spiral Arms. EROS II 3 year survey

Authors :
Derue, F.
Afonso, C.
Alard, C.
J-N, Albert
Andersen, J.
Ansari, R.
Aubourg, E.
Bareyre, P.
Bauer, F.
J-P, Beaulieu
Bouquet, A.
Char, S.
Charlot, X.
François Couchot
Coutures, C.
Ferlet, R.
J-F, Glicenstein
Goldman, B.
Gould, A.
Graff, D.
Gros, M.
Haissinski, J.
J-C, Hamilton
Hardin, D.
Kat, J.
Kim, A.
Lasserre, L.
Lesquoy, E.
Loup, C.
Magneville, C.
Mansoux, B.
J-B, Marquette
Maurice, E.
Milsztajn, A.
Moniez, M.
Palanque-Delabrouille, N.
Perdereau, O.
Prevot, L.
Regnault, N.
Rich, J.
Spiro, M.
Vidal-Madjar, A.
Vigrou, L.
Zylberajch, S.
Laboratoire de l'Accélérateur Linéaire (LAL)
Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Physique Corpusculaire et Cosmologie - Collège de France (PCC)
Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
EROS
Source :
Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2001, 373, pp.126-138, HAL
Publication Year :
2000
Publisher :
arXiv, 2000.

Abstract

We present an analysis of the light curves of 9.1 million stars observed during three seasons by EROS (Experience de Recherche d'Objets Sombres), in the Galactic plane away from the bulge. Seven stars exhibit luminosity variations compatible with gravitational microlensing effects due to unseen objects. The corresponding optical depth, averaged over four directions, is tau = 0.45 +0.24 -0.11 x 10^-6. While this value is compatible with expectations from simple galactic models under reasonable assumptions on the target distances, we find an excess of events with short timescale towards the direction closest to the Galactic Centre.<br />Comment: 4 pages, 3 figures, submitted for publication in A&A Letters

Details

ISSN :
00046361
Database :
OpenAIRE
Journal :
Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2001, 373, pp.126-138, HAL
Accession number :
edsair.doi.dedup.....3dfbbfe3bdcc764feebb0799490bc197
Full Text :
https://doi.org/10.48550/arxiv.astro-ph/0001083