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

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.

Citation

Tsapras , Y , Cassan , A , Ranc , C , Bachelet , E , Street , R , Udalski , A , Hundertmark , M , Bozza , V , Beaulieu , J P , Marquette , J B , Euteneuer , E , Bramich , D M , Dominik , M , Figuera Jaimes , R , Horne , K , Mao , S , Menzies , J , Schmidt , R , Snodgrass , C , Steele , I A , Wambsganss , J , Mróz , P , Szymański , M K , Soszyński , I , Skowron , J , Pietrukowicz , P , Kozłowski , S , Poleski , R , Ulaczyk , K , Pawlak , M , Jørgensen , U G , Skottfelt , J , Popovas , A , Ciceri , S , Korhonen , H , Kuffmeier , M , Evans , D F , Peixinho , N , Hinse , T C , Burgdorf , M J , Southworth , J , Tronsgaard , R , Kerins , E , Andersen , M I , Rahvar , S , Wang , Y , Wertz , O , Rabus , M , Calchi Novati , S , D'Ago , G , Scarpetta , G , Mancini , L , Abe , F , Asakura , Y , Bennett , D P , Bhattacharya , A , Donachie , M , Evans , P , Fukui , A , Hirao , Y , Itow , Y , Kawasaki , K , Koshimoto , N , Li , M C A , Ling , C H , Masuda , K , Matsubara , Y , Muraki , Y , Miyazaki , S , Nagakane , M , Ohnishi , K , Rattenbury , N , Saito , T , Sharan , A , Shibai , H , Sullivan , D J , Sumi , T , Suzuki , D , Tristram , P J , Yamada , T & Yonehara , A 2019 , ' An analysis of binary microlensing event OGLE-2015-BLG-0060 ' , Monthly Notices of the Royal Astronomical Society , vol. 487 , no. 4 , pp. 4603–4614 . https://doi.org/10.1093/mnras/stz1404

Publication

Monthly Notices of the Royal Astronomical Society

Status

Peer reviewed

DOI

https://doi.org/10.1093/mnras/stz1404

ISSN

0035-8711

Type

Journal article

Rights

Copyright 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This work has been made available online in accordance with the publisher's policies. This is the final published version of the work, which was originally published at https://doi.org/10.1093/mnras/stz1404

Description

Funding: UK STFC grant ST/M001296/1 (KH).