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An analysis of binary microlensing event OGLE-2015-BLG-0060

Tsapras, Y. and Calchi Novati, S. (2019) An analysis of binary microlensing event OGLE-2015-BLG-0060. Monthly Notices of the Royal Astronomical Society, 487 (4). pp. 4603-4614. ISSN 0035-8711. doi:10.1093/mnras/stz1404.

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We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes. Intensive coverage of the anomalous parts of the light curve was achieved by automated follow-up observations from the robotic telescopes of the Las Cumbres Observatory. We show that, for the first time, all main features of an anomalous microlensing event are well covered by follow-up data, allowing us to estimate the physical parameters of the lens. The strong detection of second-order effects in the event light curve necessitates the inclusion of longer-baseline survey data in order to constrain the parallax vector. We find that the event was most likely caused by a stellar binary-lens with masses M⋆1 = 0.87±0.12M⊙ and M⋆2 = 0.77±0.11M⊙⁠. The distance to the lensing system is 6.41 ± 0.14 kpc and the projected separation between the two components is 13.85 ± 0.16 au. Alternative interpretations are also considered.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Tsapras, Y.0000-0001-8411-351X
Calchi Novati, S.0000-0002-7669-1069
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 May 16. Received 2019 May 16; in original form 2018 October 18. Published: 30 May 2019. AC acknowledges financial support from Université Pierre et Marie Curie under grant Émergence@Sorbonne Universités 2016. This work was granted access to the HPC resources of the HPCaVe at UPMC-Sorbonne Université. SM was supported by the National Science Foundation of China (Grant No. 11333003, 11390372 to SM). KH acknowledges support from STFC grant ST/M001296/1. YT and JW acknowledge the support of the DFG priority program SPP 1992 Exploring the Diversity of Extrasolar Planets (WA 1047/11-1). The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to AU. Work by RAS and EB was supported by NASA grant NNX15AC97G. This work made use of observations from the LCOGT network, which includes three SUPAscopes owned by the University of St. Andrews. The MOA project is supported by JSPS KAKENHI Grant Number JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, and JP16H06287. The work by CR was supported by an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by USRA through a contract with NASA. 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. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under public survey programme ID, 177.D-3023.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Université Pierre et Marie CurieÉmergence@Sorbonne Universités 2016
National Natural Science Foundation of China11333003
National Natural Science Foundation of China11390372
Science and Technology Facilities Council (STFC)ST/M001296/1
Deutsche Forschungsgemeinschaft (DFG)SPP 1992
Deutsche Forschungsgemeinschaft (DFG)WA 1047/11-1
National Science Centre (Poland)MAESTRO 2014/14/A/ST9/00121
Japan Society for the Promotion of Science (JSPS)24253004
Japan Society for the Promotion of Science (JSPS)26247023
Japan Society for the Promotion of Science (JSPS)23340064
Japan Society for the Promotion of Science (JSPS)15H00781
Japan Society for the Promotion of Science (JSPS)JP16H06287
NASA Postdoctoral ProgramUNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Subject Keywords:gravitational lensing: micro –methods: observational – techniques: photometric – Galaxy: bulge
Issue or Number:4
Record Number:CaltechAUTHORS:20190801-075912418
Persistent URL:
Official Citation:Y Tsapras, A Cassan, C Ranc, E Bachelet, R Street, A Udalski, M Hundertmark, V Bozza, J P Beaulieu, J B Marquette, E Euteneuer, D M Bramich, M Dominik, R Figuera Jaimes, K Horne, S Mao, J Menzies, R Schmidt, C Snodgrass, I A Steele, J Wambsganss, P Mróz, M K Szymański, I Soszyński, J Skowron, P Pietrukowicz, S Kozłowski, R Poleski, K Ulaczyk, M Pawlak, U G Jørgensen, J Skottfelt, A Popovas, S Ciceri, H Korhonen, M Kuffmeier, D F Evans, N Peixinho, T C Hinse, M J Burgdorf, J Southworth, R Tronsgaard, E Kerins, M I Andersen, S Rahvar, Y Wang, O Wertz, M Rabus, S Calchi Novati, G D’Ago, G Scarpetta, L Mancini, F Abe, Y Asakura, D P Bennett, A Bhattacharya, M Donachie, P Evans, A Fukui, Y Hirao, Y Itow, K Kawasaki, N Koshimoto, M C A Li, C H Ling, K Masuda, Y Matsubara, Y Muraki, S Miyazaki, M Nagakane, K Ohnishi, N Rattenbury, To Saito, A Sharan, H Shibai, D J Sullivan, T Sumi, D Suzuki, P J Tristram, T Yamada, A Yonehara, The RoboNet team, The OGLE collaboration, The MiNDSTEp collaboration, The MOA collaboration, An analysis of binary microlensing event OGLE-2015-BLG-0060, Monthly Notices of the Royal Astronomical Society, Volume 487, Issue 4, August 2019, Pages 4603–4614,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97570
Deposited By: Tony Diaz
Deposited On:01 Aug 2019 15:12
Last Modified:16 Nov 2021 17:32

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