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A Possible Binary System of a Stellar Remnant in the High-magnification Gravitational Microlensing Event OGLE-2007-BLG-514

Miyake, N. and Kane, S. (2012) A Possible Binary System of a Stellar Remnant in the High-magnification Gravitational Microlensing Event OGLE-2007-BLG-514. Astrophysical Journal, 752 (2). Art. No. 82. ISSN 0004-637X.

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We report the extremely high-magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model that includes the effects of parallax (known orbital motion of the Earth) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 ± 0.007 and a projected separation of s = 0.072 ± 0.001 in units of the Einstein radius. The parallax parameters allow us to determine the lens distance D_L = 3.11 ± 0.39 kpc and total mass M_L = 1.40 ± 0.18 M_☉; this leads to the primary and secondary components having masses of M_1 = 1.06 ± 0.13 M_☉ and M_2 = 0.34 ± 0.04 M_☉, respectively. The parallax model indicates that the binary lens system is likely constructed by the main-sequence stars. On the other hand, we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap (possible orbital motion of the source around a companion) and parallax (q = 0.270 ± 0.005, s = 0.083 ± 0.001). The primary component of the binary lens is relatively massive, with M_1 = 0.9^(+4.6)_(–0.3) M_☉ and it is at a distance of D_L = 2.6^(+3.8)_(–0.9) kpc. Given the secure mass ratio measurement, the companion mass is therefore M_2 = 0.2^(+1.2)_(–0.1) M_☉. The xallarap model implies that the primary lens is likely a stellar remnant, such as a white dwarf, a neutron star, or a black hole.

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Kane, S.0000-0002-7084-0529
Additional Information:© 2012 American Astronomical Society. Received 2012 January 11; accepted 2012 April 12; published 2012 May 30. We acknowledge the following support: the OGLE project has received funding from the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No. 246678 to AU. The MOA project is supported by the Grant-in-Aid for Scientific Research (JSPS17340074, JSPS18253002), JSPS Research fellowships and the Global COE Program of Nagoya University “Quest for Fundamental Principles in the Universe” from JSPS and MEXT of Japan. N.M. is supported by the JSPS Research Fellowships for Young Scientists. RoboNet (K.H., D.B., M.D., R.A.S., C.S., Y.T.) acknowledges support from The Qatar Foundation via QNRF grant NPRP-09-476-1-78.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Research Council (ERC)246678
Japan Society for the Promotion of Science (JSPS)JSPS17340074
Japan Society for the Promotion of Science (JSPS)JSPS18253002
Ministry of Education, Culture, Sports, Science and Technology (MEXT)UNSPECIFIED
Qatar Foundation QNRFNPRP-09-476-1-78
Subject Keywords:binaries: general; Galaxy: bulge; gravitational lensing: micro
Issue or Number:2
Record Number:CaltechAUTHORS:20120723-103412077
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Official Citation:A Possible Binary System of a Stellar Remnant in the High-magnification Gravitational Microlensing Event OGLE-2007-BLG-514 N. Miyake et al. 2012 ApJ 752 82
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32634
Deposited By: Jason Perez
Deposited On:23 Jul 2012 20:20
Last Modified:03 Oct 2019 04:02

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