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OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing

Li, S.-S. and Shvartzvald, Y. and Calchi Novati, S. and Beichman, C. A. and Carey, S. and Henderson, C. B. (2019) OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing. Monthly Notices of the Royal Astronomical Society, 488 (3). pp. 3308-3323. ISSN 0035-8711. doi:10.1093/mnras/stz1873.

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We present the analysis of the event OGLE-2017-BLG-1186 from the 2017 Spitzer microlensing campaign. This is a remarkable microlensing event because its source is photometrically bright and variable, which makes it possible to perform an asteroseismic analysis using ground-based data. We find that the source star is an oscillating red giant with average time-scale of ∼9 d. The asteroseismic analysis also provides us source properties including the source angular size (∼27 μas) and distance (∼11.5 kpc), which are essential for inferring the properties of the lens. When fitting the light curve, we test the feasibility of Gaussian processes (GPs) in handling the correlated noise caused by the variable source. We find that the parameters from the GP model are generally more loosely constrained than those from the traditional χ^2 minimization method. We note that this event is the first microlensing system for which asteroseismology and GPs have been used to account for the variable source. With both finite-source effect and microlens parallax measured, we find that the lens is likely a ∼0.045 M⊙ brown dwarf at distance ∼9.0 kpc, or a ∼0.073 M⊙ ultracool dwarf at distance ∼9.8 kpc. Combining the estimated lens properties with a Bayesian analysis using a Galactic model, we find a ∼35 per cent probability for the lens to be a bulge object and ∼65 per cent to be a background disc object.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Li, S.-S.0000-0001-9952-7408
Shvartzvald, Y.0000-0003-1525-5041
Calchi Novati, S.0000-0002-7669-1069
Beichman, C. A.0000-0002-5627-5471
Carey, S.0000-0002-0221-6871
Henderson, C. B.0000-0001-8877-9060
Additional Information:© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2019 July 3. Received 2019 July 1; in original form 2019 April 16. Published: 10 July 2019. S-SL, WZ, and SM acknowledge support by the National Science Foundation of China (Grant No. 11821303 and 11761131004). The OGLE has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to AU. Work by YS 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. DH acknowledges support by the National Science Foundation (AST-1717000). 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 three host sites of CTIO in Chile, SAAO in South Africa, and SSO in Australia. The MOA project is supported by JSPS KAKENHI Grant Number JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, JP16H06287, and JP17H02871. Work by AG was supported by AST-1516842 from the US NSF and JPL grant 1500811. Work by PF and WZ was supported by Canada-France-Hawaii Telescope (CFHT). SD acknowledges Projects 11573003 supported by the National Science Foundation of China (NSFC). Work by CH was supported by the grant (2017R1A4A1015178) of National Research Foundation of Korea. The research has made use of data obtained at the Danish 1.54 m telescope at ESOs La Silla Observatory. YT acknowledges the support of DFG priority program SPP 1992 ‘Exploring the Diversity of Extrasolar Planets’ (WA 1047/11-1). CITEUC is funded by National Funds through FCT – Foundation for Science and Technology (project: UID/Multi/00611/2013) and FEDER – European Regional Development Fund through COMPETE 2020 – Operational Programme Competitiveness and Internationalization (project: POCI-01-0145-FEDER-006922). LM acknowledges support from the Italian Minister of Instruction, University and Research (MIUR) through FFABR 2017 fund. J-PB was supported by the University of Tasmania through the UTAS Foundation and the endowed Warren Chair in Astronomy. J-PB acknowledges the financial support of the CNES and the ANR COLD-WORLDS, ANR-18-CE31-0002. Development of the Greenhill Observatory was supported under the Australian Research Council’s LIEF funding scheme (project LE110100055). We thank C. Harlingten for the use of the H127 Telescope. This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC, Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
National Natural Science Foundation of China11821303
National Natural Science Foundation of China11761131004
National Science Centre (Poland)MAESTRO 2014/14/A/ST9/00121
NASA Postdoctoral ProgramUNSPECIFIED
Japan Society for the Promotion of Science (JSPS)JSPS24253004
Japan Society for the Promotion of Science (JSPS)JSPS26247023
Japan Society for the Promotion of Science (JSPS)JSPS23340064
Japan Society for the Promotion of Science (JSPS)JSPS15H00781
Japan Society for the Promotion of Science (JSPS)JP16H06287
Japan Society for the Promotion of Science (JSPS)JP17H02871
Canada-France-Hawaii Telescope (CFHT)UNSPECIFIED
National Natural Science Foundation of China11573003
National Research Foundation of Korea2017R1A4A1015178
Deutsche Forschungsgemeinschaft (DFG)SPP 1992
Fundação para a Ciência e a Tecnologia (FCT)UID/Multi/00611/2013
Fondo Europeo de Desarrollo Regional (FEDER)POCI-01-0145-FEDER-006922
European Regional Development FundUNSPECIFIED
Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR)FFABR 2017
University of TasmaniaUNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Agence Nationale pour la Recherche (ANR)ANR-18-CE31-0002
Australian Research CouncilLE110100055
Gaia Multilateral AgreementUNSPECIFIED
Subject Keywords:asteroseismology – gravitational lensing: micro – stars: fundamental parameters – stars: oscillations
Issue or Number:3
Record Number:CaltechAUTHORS:20190927-083917871
Persistent URL:
Official Citation:S-S Li, W Zang, A Udalski, Y Shvartzvald, D Huber, C-U Lee, T Sumi, A Gould, S Mao, P Fouqué, T Wang, S Dong, U G Jørgensen, A Cole, P Mróz, M K Szymański, J Skowron, R Poleski, I Soszyński, P Pietrukowicz, S Kozłowski, K Ulaczyk, K A Rybicki, P Iwanek, J C Yee, S Calchi Novati, C A Beichman, G Bryden, S Carey, B S Gaudi, C B Henderson, W Zhu, M D Albrow, S-J Chung, C Han, K-H Hwang, Y K Jung, Y-H Ryu, I-G Shin, S-M Cha, D-J Kim, H-W Kim, S-L Kim, D-J Lee, Y Lee, B-G Park, R W Pogge, I A Bond, F Abe, R Barry, D P Bennett, A Bhattacharya, M Donachie, A Fukui, Y Hirao, Y Itow, I Kondo, N Koshimoto, M C A Li, Y Matsubara, Y Muraki, S Miyazaki, M Nagakane, C Ranc, N J Rattenbury, H Suematsu, D J Sullivan, D Suzuki, P J Tristram, A Yonehara, G Christie, J Drummond, J Green, S Hennerley, T Natusch, I Porritt, E Bachelet, D Maoz, R A Street, Y Tsapras, V Bozza, M Dominik, M Hundertmark, N Peixinho, S Sajadian, M J Burgdorf, D F Evans, R Figuera Jaimes, Y I Fujii, L K Haikala, C Helling, T Henning, T C Hinse, L Mancini, P Longa-Peña, S Rahvar, M Rabus, J Skottfelt, C Snodgrass, J Southworth, E Unda-Sanzana, C von Essen, J-P Beaulieu, J Blackman, K Hill, OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing, Monthly Notices of the Royal Astronomical Society, Volume 488, Issue 3, September 2019, Pages 3308–3323,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:98897
Deposited By: Tony Diaz
Deposited On:27 Sep 2019 18:05
Last Modified:16 Nov 2021 17:42

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