CERN Accelerating science

Article
Report number astro-ph/9903209 ; CERN-OPEN-99-069 ; LAL-99-12
Title Observation of Microlensing towards the Galactic Spiral Arms : EROS II 2 year survey
Author(s) EROS Collaboration  Mostra tots els 44 autors
Affiliation (CERN)
Publication 1999
Imprint 30 Aug 1999
Number of pages 11
In: Astron. Astrophys.
Subject category Astrophysics and Astronomy
Accelerator/Facility, Experiment EROS
Abstract We present the analysis of the light curves of 8.5 million stars observed during two seasons by EROS (Experience de Recherche d'Objets Sombres), in the galactic plane away from the bulge. Three stars have been found that exhibit luminosity variations compatible with gravitational microlensing effects due to unseen objects. The corresponding optical depth, averaged over four directions, is 0.38 (+0.53, -0.15) 10^{-6}. All three candidates have long Einstein radius crossing times ( 70 to 100 days). For one of them, the lack of evidence for a parallax or a source size effect enabled us to constrain the lens-source % geometric configuration. Another candidate displays a modulation of the magnification, which is compatible with the lensing of a binary source. The interpretation of the optical depths inferred from these observations is hindered by the imperfect knowledge of the distance to the target stars. Our measurements are compatible with expectations from simple galactic models under reasonable assumptions on the target distances.

Corresponding record in: Inspire
Email contact: derue@lal.in2p3.fr


 Registre creat el 1999-03-16, darrera modificació el 2016-06-29


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