A Possible Binary System of a Stellar Remnant in the High-magnification Gravitational Microlensing Event OGLE-2007-BLG-514
Abstract
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.
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.Attached Files
Published - Miyake2012p18914Astrophys_J.pdf
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Additional details
- Eprint ID
- 32634
- Resolver ID
- CaltechAUTHORS:20120723-103412077
- 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)
- Qatar Foundation QNRF
- NPRP-09-476-1-78
- Created
-
2012-07-23Created from EPrint's datestamp field
- Updated
-
2022-11-22Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)