Interpretation of a short-term anomaly in the gravitational microlensing event MOA-2012-BLG-486

Interpretation of a short-term anomaly in the gravitational microlensing event MOA-2012-BLG-486

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 interp...

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Main Authors: Hwang, K., Choi, J., Bond, I., Sumi, T., Han, C., Gaudi, B., Gould, A., Bozza, V., Beaulieu, J., Tsapras, Y., Abe, F., Bennett, D., Botzler, C., Chote, P., Freeman, M., Fukui, A., Fukunaga, D., Harris, P., Itow, Y., Koshimoto, N., Ling, C., Masuda, K., Matsubara, M., Muraki, Y., Namba, S., Ohnishi, K., Rattenbury, N., Saito, T., Sullivan, D., Sweatman, W., Suzuki, D., Tristram, P., Wada, K., Yamai, N., Yock, P., Yonehara, A., Andrade de Almeida, L., DePoy, D., Dong, S., Jablonski, F., Jung, Y., Kavka, A., Lee, C., Park, H., Pogge, R., Shin, I., Yee, J., Albrow, M., Bachelet, E., Batista, V., Brillant, S., Caldwell, J., Cassan, A., Cole, A., Corrales, E., Coutures, C., Dieters, S., Dominis Prester, D., Donatowicz, J., Fouque, P., Greenhill, J., Jorgensen, U., Kane, S., Kubas, D., Marquette, J., Martin, R., Meintjes, P., Menzies, J., Pollard, K., Williams, Andrew, Wouters, D., Bramich, D., Dominik, M., Horne, K., Browne, P., Hundertmark, M., Ipatov, S., Kains, N., Snodgrass, C., Steele, I., Street, R.
Format: Journal Article
Published: Institute of Physics Publishing 2013
Subjects:
color figures
binaries
detection Online-only material
micro – planets and satellites
general – gravitational lensing
Online Access:http://iopscience.iop.org/0004-637X/778/1/55/pdf/0004-637X_778_1_55.pdf
http://hdl.handle.net/20.500.11937/14093
Description
Summary: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 clearlyresolved. 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.

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