OGLE-2003-BLG-262: Finite-Source Effects from a Point-Mass Lens**Based in part on observations obtained with the 1.3 m Warsaw Telescope at the Las Campanas Observatory of the Carnegie Institution of Washington.

We analyze OGLE-2003-BLG-262, a relatively short (tE = 12.5 0.1 day) microlensing event generated by a point-mass lens transiting the face of a K giant source in the Galactic bulge. We use the resulting finite-source effects to measure the angular Einstein radius, E = 195 17 as, and so constrain the lens mass to the FWHM interval 0.08 < M/M < 0.54. The lens-source relative proper motion is rel = 27 2 km s-1 kpc-1. Both values are typical of what is expected for lenses detected toward the bulge. Despite the short duration of the event, we detect marginal evidence for a "parallax asymmetry" but argue that this is more likely to be induced by acceleration of the source, a binary lens, or possibly by statistical fluctuations. Although OGLE-2003-BLG-262 is only the second published event to date in which the lens transits the source, such events will become more common with the new OGLE-III survey in place. We therefore give a detailed account of the analysis of this event to facilitate the study of future events of this type.

Yoo, J., DePoy, D. L., Gal-Yam, A., Gaudi, B. S., Gould, A., Han, C., ... ebru, K.

Yoo, Jaiyul||DePoy, DL||Gal-Yam, A||Gaudi, BS||Gould, A||Han, C||Lipkin, Y||Maoz, D||Ofek, EO||Park, B-G||Pogge, RW||Udalski, A||Soszyński, I||Wyrzykowski, Ł||Kubiak, M||Szymański, M||Pietrzyński, G||Szewczyk, O||Żebruń, K

OGLE-2003-BLG-262: Finite-Source Effects from a Point-Mass Lens**Based in part on observations obtained with the 1.3 m Warsaw Telescope at the Las Campanas Observatory of the Carnegie Institution of Washington. Academic Article