INTERPRETATION OF STRONG SHORT-TERM CENTRAL PERTURBATIONS IN THE LIGHT CURVES OF MODERATE-MAGNIFICATION MICROLENSING EVENTS

Journal Article · Tue Nov 10 00:00:00 EST 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/705/2/1116· OSTI ID:21378311

Han, C; Hwang, K -H; Kim, D ^[1]; Udalski, A; Szymanski, M K; Kubiak, M; Pietrzynski, G; Soszynski, I; Ulaczyk, K ^[2]; Abe, F; Fukui, A; Furusawa, K; Itow, Y ^[3]; Monard, L A. B. ^[4]; McCormick, J ^[5]; Szewczyk, O ^[6]; Wyrzykowski, L ^[7]; Bond, I A ^[8]; Botzler, C S ^[9]; Hearnshaw, J B ^[10]

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1. Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)
2. Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)
3. Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, 464-8601 (Japan)
4. Bronberg Observatory, Centre for Backyard Astrophysics Pretoria (South Africa)
5. Farm Cove Observatory, Centre for Backyard Astrophysics, Pakuranga, Auckland New Zealand (New Zealand)
6. Universidad de Concepcion, Departamento de fisica, Casilla 160-C, Concepcion (Chile)
7. Institute of Astronomy Cambridge University, Madingley Road, CB3 0HA Cambridge (United Kingdom)
8. Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland (New Zealand)
9. Department of Physics, University of Auckland, Private Bag 92019, Auckland (New Zealand)
10. University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch 8020 (New Zealand)

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.

• OSTI ID: 21378311
• Journal Information: Astrophysical Journal, Vol. 705, Issue 2; Other Information: DOI: 10.1088/0004-637X/705/2/1116; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DIAGRAMS
DISTURBANCES
GEOMETRY
PERTURBATION THEORY
PLANETS
SIGNALS
SIMULATION
VISIBLE RADIATION
ELECTROMAGNETIC RADIATION
INFORMATION
MATHEMATICS
RADIATIONS