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We present limits on the lens flux of OGLE-2007-BLG-224 based on MagAO imaging taken seven years after the microlensing event. At the time of the observations, the lens should have been separated from the microlensing source by 292 mas. However, no new sources are detected with MagAO. We place an upper limit on the lens flux of $H>20.57$. This measurement supports the conclusion of Gould et al. (2009) that the lens in this event should be a brown dwarf. This is the first test of a prediction based on the terrestrial microlens parallax effect and the first AO confirmation of a sub-stellar/dark microlens.
We report a single-lens/single-source microlensing event designated as OGLE-2019-BLG-1058. For this event, the short timescale ($sim 2.5$ days) and very fast lens-source relative proper motion ($mu_{rm rel} sim 17.6, {rm mas, yr^{-1}}$) suggest that
Parallax is the most fundamental technique to measure distances to astronomical objects. Although terrestrial parallax was pioneered over 2000 years ago by Hipparchus (ca. 140 BCE) to measure the distance to the Moon, the baseline of the Earth is so
We present the first space-based microlens parallax measurement of an isolated star. From the striking differences in the lightcurve as seen from Earth and from Spitzer (~1 AU to the West), we infer a projected velocity v_helio,projected ~ 250 km/s,
High-cadence observations of the Galactic bulge by the microlensing surveys led to the discovery of a handful of extremely short-timescale microlensing events that can be attributed to free-floating or wide-orbit planets. Here, we report the discover
In order to exhume the buried signatures of ``missing planetary caustics in the KMTNet data, we conducted a systematic anomaly search to the residuals from point-source point-lens fits, based on a modified version of the KMTNet EventFinder algorithm.