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


Skowron, J and Udalski, A and Gould, A and Dong, S and Monard, LAG and Han, C and Nelson, CR and McCormick, J and Moorhouse, D and Thornley, G and Maury, A and Bramich, DM and Greenhill, J and Kozlowski, S and Bond, I and Poleski, R and Wyrzykowski, L and Ulaczyk, K and Kubiak, M and Szymanski, MK and Pietrzynski, G and Soszynski, I and Gaudi, BS and Yee, JC and Hung, LW and Pogge, RW and DePoy, DL and Lee, CU and Park, BG and Allen, W and Mallia, F and Drummond, J and Bolt, G and Allan, A and Browne, P and Clay, N and Dominik, M and Fraser, S and Horne, K and Kains, N and Mottram, C and Snodgrass, C and Steele, I and Street, RA and Tsapras, Y and Abe, F and Bennett, DP and Botzler, CS and Douchin, D and Freeman, M and Fukui, A and Furusawa, K and Hayashi, F and Hearnshaw, JB and Hosaka, S and Itow, Y and Kamiya, K and Kilmartin, PM and Korpela, A and Lin, W and Ling, CH and Makita, S and Masuda, K and Matsubara, Y and Muraki, Y and Nagayama, T and Miyake, N and Nishimoto, K and Ohnishi, K and Perrott, YC and Rattenbury, N and Saito, To and Skuljan, L and Sullivan, DJ and Sumi, T and Suzuki, D and Sweatman, WL and Tristram, PJ and Wada, K and Yock, PCM and Beaulieu, JP and Fouque, P and Albrow, MD and Batista, V and Brillant, S and Caldwell, JAR and Cassan, A and Cole, A and Cook, KH and Coutures, CH and Dieters, S and Dominis Prester, D and Donatowicz, J and Kane, SR and Kubas, D and Marquette, JB and Martin, R and Menzies, J and Sahu, KC and Wambsganss, J and Williams, A and Zub, M, Binary microlensing event OGLE-2009-BLG-020 gives verifiable mass, distance, and orbit predictions, The Astrophysical Journal: An International Review of Astronomy and Astronomical Physics, 738, (1) Article 87. ISSN 0004-637X (2011) [Refereed Article]

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Copyright 2011 American Astronomical Society

DOI: doi:10.1088/0004-637X/738/1/87


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 verconstrained 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 Details

Item Type:Refereed Article
Keywords:binaries: general, 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:Greenhill, J (Dr John Greenhill)
UTAS Author:Cole, A (Associate Professor Andrew Cole)
UTAS Author:Dieters, S (Dr Stefan Dieters)
ID Code:73133
Year Published:2011
Web of Science® Times Cited:96
Deposited By:Mathematics and Physics
Deposited On:2011-09-15
Last Modified:2017-11-03

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