Experimental limits on the contribution of sub-stellar and stellar objects to the galactic halo

Abstract : EROS (Expérience de Recherche d'Objets Sombres) has been monitoring the luminosity of 4 million stars in the Large Magellanic Cloud in order to search for gravitational microlensing by unseen objects in the galactic halo. We present here the results from 3 years of EROS Schmidt plates data. Two stars exhibit light curves that are consistent with a sizeable microlensing effect. CCD data obtained later on revealed that one of these stars is an eclipsing binary system. Combining Schmidt plates data and the published results from our 16 CCD camera, we set upper limits on the number of unseen objects in the halo in the mass range $[10^{-7},1]\Msol$. (Submitted for publication in Astronomy and Astrophysics)