Interpretation of a Short-term Anomaly in the Gravitational Microlensing Event MOA-2012-BLG-486

November 2013 • 2013ApJ...778...55H

Authors • 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, To. • Sullivan, D. J. • Sweatman, W. L. • Suzuki, D. • Tristram, P. J. • Wada, K. • Yamai, N. • Yock, P. C. M. • Yonehara, A. • MOA Collaboration • de Almeida, L. Andrade • DePoy, D. L. • Dong, Subo • Jablonski, F. • Jung, Y. K. • Kavka, A. • Lee, C. -U. • Park, H. • Pogge, R. W. • Shin, I. -G. • Yee, J. C. • μFUN Collaboration • Albrow, M. D. • Bachelet, E. • Batista, V. • Brillant, S. • Caldwell, J. A. R. • Cassan, A. • Cole, A. • Corrales, E. • Coutures, Ch. • 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. • PLANET Collaboration • Bramich, D. M. • Dominik, M. • Horne, K. • Browne, P. • Hundertmark, M. • Ipatov, S. • Kains, N. • Snodgrass, C. • Steele, I. A. • Street, R. A. • RoboNet Collaboration

Abstract • 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.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2013ApJ...778...55H
• PDF https://stacks.iop.org/0004-637X/778/55/pdf
• PREPRINT http://arxiv.org/abs/1308.5762
• ELECTR https://doi.org/10.1088%2F0004-637X%2F778%2F1%2F55