OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected From Spitzer Only (2018)
AuthorsWang T, Novati SC, Udalski A, Gould A, Mao S, Zang W, Beichman C, Bryden G, Carey S, Gaudi BS, Henderson CB, Shvartzvald Y, Yee JC, Mroz P, Poleski R, Skowron J, Szymanski MK, Soszynski I, Kozlowski S, Pietrukowicz P, Ulaczyk K, Pawlak M, Albrow MD, Chung S-J, Han C, Hwang K-H, Jung YK, Ryu Y-H, Shin I-G, Zhu W, Cha S-M, Kim D-J, Kim H-W, Kim S-L, Lee C-U, Lee D-J, Lee Y, Park B-G, Pogge RWshow all
We analyze the binary gravitational microlensing event OGLE-2017-BLG-1130 (mass ratio q~0.45), the first published case in which the binary anomaly was only detected by the Spitzer Space Telescope. This event provides strong evidence that some binary signals can be missed by observations from the ground alone but detected by Spitzer. We therefore invert the normal procedure, first finding the lens parameters by fitting the space-based data and then measuring the microlensing parallax using ground-based observations. We also show that the normal four-fold space-based degeneracy in the single-lens case can become a weak eight-fold degeneracy in binary-lens events. Although this degeneracy is resolved in event OGLE-2017-BLG-1130, it might persist in other events.
ANZSRC Fields of Research02 - Physical Sciences::0201 - Astronomical and Space Sciences::020102 - Astronomical and Space Instrumentation
02 - Physical Sciences::0201 - Astronomical and Space Sciences