2003ApJ...599L..17R

We report the detection of the first two microlensing candidates from the Wendelstein Calar Alto Pixellensing Project (WeCAPP). Both are detected with a high signal-to-noise ratio and were filtered out from 4.5 million pixel light curves using a variety of selection criteria. Here we only consider well-sampled events with timescales of 1 day<t_fwhm<20 days, high amplitudes, and a low χ² of the microlensing fit. The two-color photometry (R,I) shows that the events are achromatic and that giant stars with colors of (R-I)~1.1 mag in the bulge of M31 have been lensed. The magnification factors are 64 and 10, which are obtained for typical giant luminosities of M_I=-2.5 mag. Both lensing events lasted for only a few days (t^GL1_fwhm=1.7 days and t^GL2_fwhm=5.4 days). The event GL1 is likely identical with PA-00-S3 reported by the POINT-AGAPE project. Our calculations favor in both cases the possibility that MACHOs in the halo of M31 caused the lensing events. The most probable masses, 0.08 M_☉for GL1 and 0.02 M_☉for GL2, are in the range of the brown dwarf limit of hydrogen burning. Solar mass objects are a factor of 2 less likely.