A New Type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-Magnification Gravitational Microlensing Events
J. -Y. Choi, I. -G. Shin, C. Han, A. Udalski, T. Sumi, A. Gould, V. Bozza, M. Dominik, P. Fouqué, K. Horne, M. K. Szymański, M. Kubiak, I. Soszyński, G. Pietrzy… 展开作者
J. -Y. Choi, I. -G. Shin, C. Han, A. Udalski, T. Sumi, A. Gould, V. Bozza, M. Dominik, P. Fouqué, K. Horne, M. K. Szymański, M. Kubiak, I. Soszyński, G. Pietrzyński, R. Poleski, K. Ulaczyk, P. Pietrukowicz, S. Kozłowski, J. Skowron, Ł. Wyrzykowski, F. Abe, D. P. Bennett, I. A. Bond, C. S. Botzler, P. Chote, M. Freeman, A. Fukui, K. Furusawa, Y. Itow, S. Kobara, C. H. Ling, K. Masuda, Y. Matsubara, N. Miyake, Y. Muraki, K. Ohmori, K. Ohnishi, N. J. Rattenbury, To. Saito, D. J. Sullivan, D. Suzuki, K. Suzuki, W. L. Sweatman, S. Takino, P. J. Tristram, K. Wada, P. C. M. Yock, D. M. Bramich, C. Snodgrass, I. A. Steele, R. A. Street, Y. Tsapras, K. A. Alsubai, P. Browne, M. J. Burgdorf, S. Calchi Novati, P. Dodds, S. Dreizler, X. -S. Fang, F. Grundahl, C. -H. Gu, S. Hardis, K. Harpsøe, T. C. Hinse, A. Hornstrup, M. Hundertmark, J. Jessen-Hansen, U. G. Jørgensen, N. Kains, E. Kerins, C. Liebig, M. Lund, M. Lunkkvist, L. Mancini, M. Mathiasen, M. T. Penny, S. Rahvar, D. Ricci, G. Scarpetta, J. Skottfelt, J. Southworth, J. Surdej, J. Tregloan-Reed, J. Wambsganss, O. Wertz, L. A. Almeida, V. Batista, G. Christie, D. L. DePoy, Subo Dong, B. S. Gaudi, C. Henderson, F. Jablonski, C. -U. Lee, J. McCormick, D. McGregor, D. Moorhouse, T. Natusch, H. Ngan, S. -Y. Park, R. W. Pogge, T. -G. Tan, G. Thornley, J. C. Yee, M. D. Albrow, E. Bachelet, J. -P. Beaulieu, S. Brillant, A. Cassan, A. A. Cole, E. Corrales, C. Coutures, S. Dieters, D. Dominis Prester, J. Donatowicz, J. Greenhill, D. Kubas, J. -B. Marquette, J. W. Menzies, K. C. Sahu, M. Zub
High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally distinguished due to the basically different magnification pattern around caustics. In this paper, we present a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations. The peak of a lensing light curve affected by this perturbation appears to be blunt and flat. For a planetary case, this perturbation occurs when the source trajectory passes the negative perturbation region behind the back end of an arrowhead-shaped central caustic. For a binary case, a similar perturbation occurs for a source trajectory passing through the negative perturbation region between two cusps of an astroid-shaped caustic. We demonstrate the degeneracy for 2 high-magnification events of OGLE-2011-BLG-0526 and OGLE-2011-BLG-0950/MOA-2011-BLG-336. For OGLE-2011-BLG-0526, the $χ^2$ difference between the planetary and binary model is $\sim$ 3, implying that the degeneracy is very severe. For OGLE-2011-BLG-0950/MOA-2011-BLG-336, the stellar binary model is formally excluded with $Δχ^2 \sim$ 105 and the planetary model is preferred. However, it is difficult to claim a planet discovery because systematic residuals of data from the planetary model are larger than the difference between the planetary and binary models. Considering that 2 events observed during a single season suffer from such a degeneracy, it is expected that central perturbations experiencing this type of degeneracy is common.
Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. V. Detection Rates of Multiplanetary Systems in High Magnification Microlensing Events
INAF -- IAPS（意大利国家天体物理研究所-国际天体物理学中心）；Università di Napoli Federico II（那不勒斯费德里科二世大学）；INFN -- Sezione di Napoli（意大利国家核物理研究所-那不勒斯分部）；Université Marie et Louis Pasteur, CNRS, Institut UTINAM UMR 6213（玛丽和路易·巴斯德大学、法国国家科学研究中心、UTINAM联合研究实验室）；IPAC, Caltech（加州理工学院红外处理与分析中心）；Università di Salerno（萨莱诺大学）；INAF -- Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所-卡波迪蒙特天文台）；Louisiana State University（路易斯安那州立大学）；University of Canterbury（坎特伯雷大学）；Space Telescope Science Institute（太空望远镜科学研究所）；NASA Exoplanet Science Institute（NASA系外行星科学研究所）；University of Maryland（马里兰大学）；NASA Goddard Space Flight Center（NASA戈达德太空飞行中心）；The Ohio State University（俄亥俄州立大学）；The Johns Hopkins University（约翰斯·霍普金斯大学）；Catholic University of America（美国天主教大学）；Center for Research and Exploration in Space Science and Technology, NASA/GSFC（NASA/戈达德太空飞行中心空间科学与技术探索与研究中心）；University of California Berkeley（加州大学伯克利分校）；University of Manchester（曼彻斯特大学）；Lehigh University（利哈伊大学）；Las Cumbres Observatory（拉斯坎布雷斯天文台）；Observatories of the Carnegie Institution for Science（卡内基科学促进会天文台）；Vanderbilt University（范德堡大学）；Osaka University（大阪大学）；Westlake University（西湖大学）
