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Binary microlensing event OGLE-2009-BLG-020 gives verifiable mass, distance, and orbit predictions

Skowron, J.; Udalski, A.; Gould, A.; Dong, Subo; Monard, L. A. G.; Han, C.; Nelson, C. R.; McCormick, J.; Moorhouse, D.; Thornley, G.; Maury, A.; Bramich, D. M.; Greenhill, J.; Kozłowski, S.; Bond, I.; Poleski, R.; Wyrzykowski, Ł.; Ulaczyk, K.; Kubiak, M.; Szymański, M. K.; Pietrzyński, G.; Soszyński, I.; Gaudi, B. S.; Yee, J. C.; Hung, L.-W.; Pogge, R. W.; DePoy, D. L.; Lee, C.-U.; Park, B.-G.; Allen, W.; Mallia, F.; Drummond, J.; Bolt, G.; Allan, A.; Browne, P.; Clay, N.; Dominik, M.; Fraser, S.; Horne, K.; Kains, N.; Mottram, C.; Snodgrass, C.; Steele, I.; Street, R. A.; Tsapras, Y.; Abe, F.; Bennett, D. P.; Botzler, C. S.; Douchin, D.; Freeman, M.; Fukui, A.; Furusawa, K.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagayama, T.; Miyake, N.; Nishimoto, K.; Ohnishi, K.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; Beaulieu, J.-P.; Fouqué, P.; Albrow, M. D.; Batista, V.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Cook, K. H.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Kane, S. R.; Kubas, D.; Marquette, J.-B.; Martin, R.; Menzies, J.; Sahu, K. C.; Wambsganss, J.; Williams, A. and Zub, M. (2011). Binary microlensing event OGLE-2009-BLG-020 gives verifiable mass, distance, and orbit predictions. Astrophysical Journal, 738(1), article no. 87.

DOI (Digital Object Identifier) Link: https://doi.org/10.1088/0004-637X/738/1/87
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Abstract

We present the first example of binary microlensing for which the parameter measurements can be verified (or contradicted) by future Doppler observations. This test is made possible by a confluence of two relatively unusual circumstances. First, the binary lens is bright enough (I = 15.6) to permit Doppler measurements. Second, we measure not only the usual seven binary-lens parameters, but also the "microlens parallax" (which yields the binary mass) and two components of the instantaneous orbital velocity. Thus, we measure, effectively, six "Kepler+1" parameters (two instantaneous positions, two instantaneous velocities, the binary total mass, and the mass ratio). Since Doppler observations of the brighter binary component determine five Kepler parameters (period, velocity amplitude, eccentricity, phase, and position of periapsis), while the same spectroscopy yields the mass of the primary, the combined Doppler + microlensing observations would be overconstrained by 6 + (5 + 1) – (7 + 1) = 4 degrees of freedom. This makes possible an extremely strong test of the microlensing solution. We also introduce a uniform microlensing notation for single and binary lenses, define conventions, summarize all known microlensing degeneracies, and extend a set of parameters to describe full Keplerian motion of the binary lenses.

Item Type: Journal Item
Copyright Holders: 2011 The American Astronomical Society
ISSN: 1538-4357
Extra Information: 21 pp.
Keywords: binaries; galaxies; galactic bulge; gravitational lensing
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Research Group: Space
Item ID: 43076
Depositing User: Colin Snodgrass
Date Deposited: 27 May 2015 12:17
Last Modified: 07 Dec 2018 10:31
URI: http://oro.open.ac.uk/id/eprint/43076
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