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OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected from Spitzer Only

Wang, Tianshu and Calchi Novati, S. and Beichman, C. and Carey, S. (2018) OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected from Spitzer Only. Astrophysical Journal, 860 (1). Art. No. 25. ISSN 1538-4357. doi:10.3847/1538-4357/aabcd2.

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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 detected only 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Calchi Novati, S.0000-0002-7669-1069
Beichman, C.0000-0002-5627-5471
Carey, S.0000-0002-0221-6871
Additional Information:© 2018 The American Astronomical Society. Received 2018 February 25; revised 2018 April 4; accepted 2018 April 5; published 2018 June 7. This work has been supported in part by the National Natural Science Foundation of China (NSFC) grants 11333003 and 11390372 (S.M.). This research has made use of the KMTNet system operated by the Korea Astronomy and Space Science Institute (KASI) and the data were obtained at the three host sites of CTIO in Chile, SAAO in South Africa, and SSO in Australia. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U.. Work by W.Z., Y.K.J., and A.G. was supported by AST-1516842 from the US NSF. W.Z., I.G.S., and A.G. were supported by JPL grant 1500811. Work by C.H. was supported by the grant (2017R1A4A101517) of National Research Foundation of Korea. Work by Y.S. was supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, California Institute of Technology, administered by Universities Space Research Association through a contract with NASA. This work is based (in part) on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. Software: VBBinaryLensing (Bozza 2010), Scipy (Jones et al. 2001), Numpy (Oliphant 2006), Matplotlib (Hunter 2007), emcee (Foreman-Mackey et al. 2013).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
National Natural Science Foundation of China11333003
National Natural Science Foundation of China11390372
National Science Centre (Poland)MAESTRO 2014/14/A/ST9/00121
National Research Foundation of Korea2017R1A4A101517
NASA Postdoctoral ProgramUNSPECIFIED
Subject Keywords:binaries: general – gravitational lensing: micro
Issue or Number:1
Record Number:CaltechAUTHORS:20180607-105615895
Persistent URL:
Official Citation:Tianshu Wang et al 2018 ApJ 860 25
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86883
Deposited By: Tony Diaz
Deposited On:07 Jun 2018 18:27
Last Modified:15 Nov 2021 20:43

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