MICROLENSING BINARIES DISCOVERED THROUGH HIGH-MAGNIFICATION CHANNEL

Journal Article · Mon Feb 20 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/746/2/127· OSTI ID:22011720

Shin, I -G; Choi, J -Y; Park, S -Y; Han, C ^[1]; Gould, A; Gaudi, B S ^[2]; Sumi, T ^[3]; Udalski, A ^[4]; Beaulieu, J -P ^[5]; Dominik, M ^[6]; Allen, W ^[7]; Bos, M ^[8]; Christie, G W ^[9]; Depoy, D L ^[10]; Dong, S ^[11]; Drummond, J ^[12]; Gal-Yam, A ^[13]; Hung, L -W ^[14]; Janczak, J ^[15]; Kaspi, S ^[16] ; Consortium, MiNDSTEp; others, and

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1. Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of)
2. Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States)
3. Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan)
4. Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)
5. Institut d'Astrophysique de Paris, UMR7095 CNRS-Universite Pierre and Marie Curie, 98 bis Boulevard Arago, 75014 Paris (France)
6. School of Physics and Astronomy, SUPA, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom)
7. Vintage Lane Observatory, Blenheim (New Zealand)
8. Molehill Astronomical Observatory, North Shore (New Zealand)
9. Auckland Observatory, P.O. Box 24-180, Auckland (New Zealand)
10. Department of Physics, Texas A and M University, College Station, TX (United States)
11. Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)
12. Possum Observatory, Patutahi (New Zealand)
13. Benoziyo Center for Astrophysics, the Weizmann Institute (Israel)
14. Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States)
15. Department of Physics, Ohio State University, 191 W. Woodruff, Columbus, OH 43210 (United States)
16. School of Physics and Astronomy, Tel-Aviv University, Tel Aviv 69978 (Israel)

Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturbations, which are confined near the peak of the light curves, can be easily distinguished from the central perturbations caused by planets. However, the degeneracy between close and wide binary solutions cannot be resolved with a 3{sigma} confidence level for three events, implying that the degeneracy would be an important obstacle in studying binary distributions. The dependence of the degeneracy on the lensing parameters is consistent with a theoretical prediction that the degeneracy becomes severe as the binary separation and the mass ratio deviate from the values of resonant caustics. The measured mass ratio of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is q {approx} 0.1, making the companion of the lens a strong brown dwarf candidate.

• OSTI ID: 22011720
• Journal Information: Astrophysical Journal, Vol. 746, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BINARY STARS
MASS
PERTURBATION THEORY
PLANETS
VISIBLE RADIATION