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Characterizing lenses and lensed stars of high-magnification single-lens gravitational microlensing events with lenses passing over source starts
Citation
Choi, J-Y and Shin, I-G and Park, S-Y and Han, C and Gould, A and Sumi, T and Udalski, A and Beaulieu, J-P and Street, R and Dominik, M and Cole, AA and Greenhill, JG and The MuFUN Collaboration, The MOA Collaboration, The OGLE Collaboration, The PLANET Collaboration, The RoboNet Collaboration, The MiNDSTEp Consortium, Characterizing lenses and lensed stars of high-magnification single-lens gravitational microlensing events with lenses passing over source starts, The Astrophysical Journal, 751, (1) Article 41. ISSN 0004-637X (2012) [Refereed Article]
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Copyright Statement
Copyright 2012 The American Astronomical Society
DOI: doi:10.1088/0004-637X/751/1/41
Abstract
We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of θE ~ 0.08 mas combined with the short timescale of tE ~ 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of ~0.84 M☉ is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | Galaxy: bulge; gravitational lensing: micro |
| Research Division: | Physical Sciences |
| Research Group: | Astronomical sciences |
| Research Field: | Stellar astronomy and planetary systems |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding knowledge |
| Objective Field: | Expanding knowledge in the physical sciences |
| UTAS Author: | Cole, AA (Associate Professor Andrew Cole) |
| UTAS Author: | Greenhill, JG (Dr John Greenhill) |
| ID Code: | 79939 |
| Year Published: | 2012 |
| Web of Science® Times Cited: | 25 |
| Deposited By: | Mathematics and Physics |
| Deposited On: | 2012-10-15 |
| Last Modified: | 2017-11-06 |
| Downloads: | 0 |
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