We present the analysis of the caustic-crossing binary microlensing event OGLE-2017-BLG-0039. Thanks to the very long duration of the event, with an event time scale tE∼130 days, the microlens parallax is precisely measured despite its small value of \pie∼0.06. The analysis of the well-resolved caustic crossings during both the source star's entrance and exit of the caustic yields the angular Einstein radius \thetae∼0.6~mas. The measured \pie and \thetae indicate that the lens is a binary composed of two stars with masses ∼1.0M⊙ and ∼0.15M⊙, and it is located at a distance of ∼6 kpc. From the color and brightness of the lens estimated from the determined lens mass and distance, it is expected that ∼2/3 of the I-band blended flux comes from the lens. Therefore, the event is a rare case of a bright lens event for which high-resolution follow-up observations can confirm the nature of the lens.
@article{arxiv.1809.10831,
title = {OGLE-2017-BLG-0039: Microlensing Event with Light from the Lens Identified from Mass Measurement},
author = {C. Han and Y. K. Jung and A. Udalski and I. Bond and V. Bozza and M. D. Albrow and S. -J. Chung and A. Gould and K. -H. Hwang and D. Kim and C. -U. Lee and H. -W. Kim and Y. -H. Ryu and I. -G. Shin and J. C. Yee and Y. Shvartzvald and S. -M. Cha and S. -L. Kim and D. -J. Kim and D. -J. Lee and Y. Lee and B. -G. Park and R. W. Pogge and M. K. Szymański and P. Mróz and J. Skowron and R. Poleski and I. Soszyński and S. Kozłowski and P. Pietrukowicz and K. Ulaczyk and M. Pawlak and F. Abe and R. Barry and D. P. Bennett and A. Bhattacharya and M. Donachie and P. Evans and A. Fukui and Y. Hirao and Y. Itow and K. Kawasaki and N. Koshimoto and M. C. A. Li and C. H. Ling and Y. Matsubara and S. Miyazaki and H. Munakata and Y. Muraki and M. Nagakane and K. Ohnishi and C. Ranc and N. Rattenbury and T. Saito and A. Sharan and D. J. Sullivan and T. Sumi and D. Suzuki and P. J. Tristram and T. Yamada and A. Yonehara},
journal= {arXiv preprint arXiv:1809.10831},
year = {2018}
}