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تسجيل مستخدم جديدGalactic Bulge Microlensing Optical Depth from EROS-2
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We present a new EROS-2 measurement of the microlensing optical depth toward the Galactic Bulge. Light curves of $5.6times 10^{6}$ clump-giant stars distributed over $66 deg^2$ of the Bulge were monitored during seven Bulge seasons. 120 events were found with apparent amplifications greater than 1.6 and Einstein radius crossing times in the range $5 {rm d}<t_e <400 {rm d}$. This is the largest existing sample of clump-giant events and the first to include northern Galactic fields. In the Galactic latitude range $1.4degr<|b|<7.0degr$, we find $tau/10^{-6}=(1.62 pm 0.23)exp[-a(|b|-3 {rm deg})]$ with $a=(0.43 pm0.16)deg^{-1}$. These results are in good agreement with our previous measurement, with recent measurements of the MACHO and OGLE-II groups, and with predictions of Bulge models.
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