Interpretation of Strong Short-term Central Perturbations in the Light Curves of Moderate-Magnification Microlensing Events
journal contribution
posted on 2023-05-17, 00:34authored byHan, C, Hwang, KH, Kim, D, Udalski, A, Abe, F, Monard, LAB, McCormick, J, Szymanski, MK, Kubiak, M, Pietrzynski, G, Soszynski, I, Szewczyk, O, Wyrzykowski, L, Ulaczyk, K, Bond, IA, Botzler, CS, Fukui, A, Furusawa, K, Hearnshaw, JB, Itow, Y, Kamiya, K, Kilmartin, PM, Korpela, A, Lin, W, Ling, CH, Masuda, K, Matsubara, Y, Miyake, N, Muraki, Y, Nagaya, M, Ohnishi, K, Tokumura, T, Perrott, YC, Rattenbury, N, Saito, T, Sako, T, Skuljan, L, Sullivan, DS, Sumi, T, Sweatman, WL, Tristram, PJ, Yock, PCM, Allen, W, Christie, GW, DePoy, DL, Dong, S, Gaudi, BS, Gould, A, Lee, CU, Natusch, T, Park, BG, Pogge, RW, Albrow, MD, Allan, A, Batista, V, Beaulieu, JP, Bennett, DP, Brilliant, S, Bode, M, Bramich, DM, Burgdorf, M, Caldwell, JAR, Calitz, H, Cassan, A, Corrales, E, Dieters, S, Prester, DD, Dominik, M, Donatowicz, J, Fouque, P, Greenhill, JG, Kym HillKym Hill, Hoffman, M, Horne, K, Jorgensen, UG, Kains, N, Kubas, D, Marquette, JB, Martin, R, Meintjes, P, Menzies, J, Pollard, KR, Sahu, KC, Snodgrass, C, Steele, I, Street, R, Tsapras, Y, Wambsganss, J, Williams, A, Zub, M
To improve the planet detection efficiency, current planetary microlensing experiments are focused on high magnification events searching for planetary signals near the peak of lensing light curves. However, it is known that central perturbations can also be produced by binary companions and thus it is important to distinguish planetary signals from those induced by binary companions. In this paper, we analyze the light curves of microlensing events OGLE-2007-BLG-137/MOA-2007-BLG-091, OGLE-2007-BLG-355/MOA-2007-BLG-278, and MOA- 2007-BLG-199/OGLE-2007-BLG-419, for all of which exhibit short-term perturbations near the peaks of the light curves. From detailed modeling of the light curves, we find that the perturbations of the events are caused by binary companions rather than planets. From a close examination of the light curves combined with the underlying physical geometry of the lens system obtained from modeling, we find that the short timescale caustic-crossing feature occurring at a low or a moderate base magnification with an additional secondary perturbation is a typical feature of binary-lens events and thus can be used for the discrimination between the binary and planetary interpretations.
History
Publication title
The Astrophysical Journal: An International Review of Astronomy and Astronomical Physics
Volume
705
Pagination
1116-1121
ISSN
0004-637X
Department/School
School of Natural Sciences
Publisher
Univ Chicago Press
Place of publication
1427 E 60Th St, Chicago, USA, Il, 60637-2954
Rights statement
C? 2009. The American Astronomical Society. All rights reserved.