We analyze MOA-2010-BLG-311, a high magnification (A max > 600) microlensing event with complete data coverage over the peak, making it very sensitive to planetary signals. We fit this event with both a point lens and a two-body lens model and find that the two-body lens model is a better fit but with only Δχ2 ∼ 80. The preferred mass ratio between the lens star and its companion is q = 10-3.7 ± 0.1, placing the candidate companion in the planetary regime. Despite the formal significance of the planet, we show that because of systematics in the data the evidence for a planetary companion to the lens is too tenuous to claim a secure detection. When combined with analyses of other high-magnification events, this event helps empirically define the threshold for reliable planet detection in high-magnification events, which remains an open question. © 2013. The American Astronomical Society. All rights reserved.
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Yee, J., Hung, L., Bond, I., Allen, W., Monard, L., Albrow, M., Fouqué, P., Dominik, M., Tsapras, Y., Udalski, A., Gould, A., Zellem, R., Bos, M., Christie, G., Depoy, D., Dong, S., Drummond, J., Gaudi, B., Gorbikov, E., Han, C., Kaspi, S., Klein, N., Lee, C., Maoz, D., McCormick, J., Moorhouse, D., Natusch, T., Nola, M., Park, B., Pogge, R., Polishook, D., Shporer, A., & Shvartzvald, Y. (2013). MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detection. Astrophysical Journal, 769 (1) https://doi.org/10.1088/0004-637X/769/1/77