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Characterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars

Choi, J.-Y. and Kane, S. R. (2012) Characterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars. Astrophysical Journal, 751 (1). p. 41. ISSN 0004-637X. https://resolver.caltech.edu/CaltechAUTHORS:20120607-094130720

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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 θ_E ~ 0.08 mas combined with the short timescale of t_E ~ 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 Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/0004-637X/751/1/41DOIArticle
http://iopscience.iop.org/0004-637X/751/1/41PublisherArticle
ORCID:
AuthorORCID
Kane, S. R.0000-0002-7084-0529
Additional Information:© 2012 American Astronomical Society. Received 2011 November 17; accepted 2012 March 19; published 2012 May 2. Work by C.H. was supported by the Creative Research Initiative Program (2009-0081561) of the National Research Foundation of Korea. The MOA experiment was supported by JSPS17340074, JSPS18253002, JSPS20340052, JSPS22403003, and JSPS23340064. 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. Work by B.S.G. and A.G. was supported in part by NSF grant AST-1103471. Work by B.S.G., A.G., R.W.P., and J.C.Y. was supported in part by NASA grant NNX08AF40G. Work by J.C.Y. was supported by a National Science Foundation Graduate Research Fellowship under grant No. 2009068160. C.B.H. acknowledges the support of NSF Graduate Research Fellowship 2011082275. T.S. was supported by the grants JSPS18749004, MEXT19015005, and JSPS20740104. F.F., D.R., and J.S. were supported by the Communauté française de Belgique–Actions de recherche concertées–Académie universitaire Wallonie-Europe.
Group:Infrared Processing and Analysis Center (IPAC)
Funders:
Funding AgencyGrant Number
National Research Foundation of Korea2009-0081561
Japan Society for the Promotion of Science (JSPS)JSPS17340074
Japan Society for the Promotion of Science (JSPS)JSPS18253002
Japan Society for the Promotion of Science (JSPS)JSPS20340052
Japan Society for the Promotion of Science (JSPS)JSPS22403003
Japan Society for the Promotion of Science (JSPS)JSPS23340064
European Community Seventh Framework ProgrammeFP7/2007-2013
European Research Council (ERC)246678
NSFAST-1103471
NASANNX08AF40G
NSF Graduate Research Fellowship2009068160
NSF Graduate Research Fellowship2011082275
Japan Society for the Promotion of Science (JSPS)JSPS18749004
Ministry of Education, Culture, Sports, Science and Technology (MEXT), JapanMEXT19015005
Japan Society for the Promotion of Science (JSPS)JSPS20740104
Communauté française de BelgiqueUNSPECIFIED
Subject Keywords:Galaxy: bulge; gravitational lensing: micro
Issue or Number:1
Record Number:CaltechAUTHORS:20120607-094130720
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20120607-094130720
Official Citation:Characterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars J.-Y. Choi et al. 2012 ApJ 751 41
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:31834
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:07 Jun 2012 20:57
Last Modified:03 Oct 2019 03:55

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