* Astronomy

Title: OGLE-2016-BLG-0168 Binary Microlensing Event: Prediction and Confirmation of the Micorlens Parallax Effect from Space-based Observation
Author: I.-G. Shin, A. Udalski, J. C. Yee, S. Calchi Novati, C. Han, J. Skowron, P. Mróz, I. Soszyski, R. Poleski, M. K. Szymaski, S. Kozowski, P. Pietrukowicz, K. Ulaczyk, M. Pawlak, M. D. Albrow, A. Gould, S.-J. Chung, K.-H. Hwang, Y. K. Jung, Y.-H. Ryu, W. Zhu, S.-M. Cha, D.-J. Kim, H.-W. Kim, S.-L. Kim, C.-U. Lee, Y. Lee, B.-G. Park, R. W. Pogge, C. Beichman, G. Bryden, S. Carey, B. S. Gaudi, C. B. Henderson, Y. Shvartzvald

The microlens parallax is a crucial observable for conclusively identifying the nature of lens systems in microlensing events containing or composed of faint (even dark) astronomical objects such as planets, neutron stars, brown dwarfs, and black holes. With the commencement of a new era of microlensing in collaboration with space-based observations, the microlens parallax can be routinely measured. In addition, space-based observations can provide opportunities to verify the microlens parallax measured from ground-only observations and to find a unique solution of the lensing lightcurve analysis. However, since most space-based observations cannot cover the full lightcurves of lensing events, it is also necessary to verify the reliability of the information extracted from fragmentary space-based lightcurves. We conduct a test based on the microlensing event OGLE-2016-BLG-0168 created by a binary lens system consisting of almost equal mass M-dwarf stars to demonstrate that it is possible to verify the microlens parallax and to resolve degeneracies by using the space-based lightcurve even though the observations are fragmentary. Since space-based observatories will frequently produce fragmentary lightcurves due to their short observing windows, the methodology of this test will be useful for next-generation microlensing experiments that combine space-based and ground-based collaboration.

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