Interpretation of a short-term anomaly in the gravitational microlensing event MOA-2012-BLG-486
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A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity between the planetary and binary-source interpretations. In this paper, we present the analysis of the microlensing event MOA-2012-BLG-486, for which the light curve exhibits a short-lived perturbation. Routine modeling not considering data taken in different passbands yields a best-fit planetary model that is slightly preferred over the best-fit binary-source model. However, when allowed for a change in the color during the perturbation, we find that the binary-source model yields a significantly better fit and thus the degeneracy is clearly resolved. This event not only signifies the importance of considering various interpretations of short-term anomalies, but also demonstrates the importance of multi-band data for checking the possibility of false-positive planetary signals.
Hwang , K-H , Choi , J-Y , Bond , I A , Sumi , T , Han , C , Gaudi , B S , Gould , A , Bozza , V , Beaulieu , J-P , Tsapras , Y , Abe , F , Bennett , D P , Botzler , C S , Chote , P , Freeman , M , Fukui , A , Fukunaga , D , Harris , P , Itow , Y , Koshimoto , N , Ling , C H , Masuda , K , Matsubara , Y , Muraki , Y , Namba , S , Ohnishi , K , Rattenbury , N J , Saito , T , Sullivan , D J , Sweatman , W L , Suzuki , D , Tristram , P J , Wada , K , Yamai , N , Yock , P C M , Yonehara , A , de Almeida , L A , DePoy , D L , Dong , S , Jablonski , F , Jung , Y K , Kavka , A , Lee , C-U , Park , H , Pogge , R W , Shin , I-G , Yee , J C , Albrow , M D , Bachelet , E , Batista , V , Brillant , S , Caldwell , J A R , Cassan , A , Cole , A , Corrales , E , Coutures , C , Dieters , S , Dominis Prester , D , Donatowicz , J , Fouqué , P , Greenhill , J , Jørgensen , U G , Kane , S R , Kubas , D , Marquette , J-B , Martin , R , Meintjes , P , Menzies , J , Pollard , K R , Williams , A , Wouters , D , Bramich , D M , Dominik , M , Horne , K , Browne , P , Hundertmark , M , Ipatov , S , Kains , N , Snodgrass , C , Steele , I A & Street , R A 2013 , ' Interpretation of a short-term anomaly in the gravitational microlensing event MOA-2012-BLG-486 ' Astrophysical Journal , vol 778 , no. 1 , 55 . DOI: 10.1088/0004-637X/778/1/55
© 2013. The American Astronomical Society. All rights reserved.
D.M.B., M.D., K.H., M.H., S.I., C.S., R.A.S., and Y.T. are supported by NPRP grant NPRP-09-476-1-78 from the Qatar National Research Fund (a member of Qatar Foundation). K.H. is supported by a Royal Society Leverhulme Senior Research Fellowship.
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