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A systematic fitting scheme for caustic-crossing microlensing events

Kains, N. and Cassan, A. and Horne, K. and Albrow, M. D. and Dieters, S. and Fouqué, P. and Greenhill, J. and Udalski, A. and Zub, M. and Bennett, D. P. and Dominik, M. and Donatowicz, J. and Kubas, D. and Tsapras, Y. and Anguita, T. and Batista, V. and Beaulieu, J. P. and Brillant, S. and Bode, M. and Bramich, D. M. and Burgdorf, M. and Caldwell, J. A. R. and Cook, K. H. and Coutures, Ch. and Dominis-Prester, D. and Jørgensen, U. G. and Kane, S. and Marquette, J. B. and Martin, R. and Menzies, J. and Pollard, K. R. and Rattenbury, N. and Sahu, K. C. and Snodgrass, C. and Steele, I. and Vinter, C. and Wambsganss, J. and Williams, A. and Kubiak, M. and Pietrzyński, G. and Soszyński, I. and Szewczyk, O. and Szymański, M. K. and Ulaczyk, K. and Wyrzykowski, Ł. (2009) A systematic fitting scheme for caustic-crossing microlensing events. Monthly Notices of the Royal Astronomical Society, 395 (2). pp. 787-796. ISSN 0035-8711.

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We outline a method for fitting binary-lens caustic-crossing microlensing events based on the alternative model parametrization proposed and detailed by Cassan. As an illustration of our methodology, we present an analysis of OGLE-2007-BLG-472, a double-peaked Galactic microlensing event with a source crossing the whole caustic structure in less than three days. In order to identify all possible models we conduct an extensive search of the parameter space, followed by a refinement of the parameters with a Markov Chain Monte Carlo algorithm. We find a number of low- χ2 regions in the parameter space, which lead to several distinct competitive best models. We examine the parameters for each of them, and estimate their physical properties. We find that our fitting strategy locates several minima that are difficult to find with other modelling strategies and is therefore a more appropriate method to fit this type of event.

Item Type:Article
Related URLs:
URLURL TypeDescription
Albrow, M. D.0000-0003-3316-4012
Udalski, A.0000-0001-5207-5619
Bennett, D. P.0000-0001-8043-8413
Dominik, M.0000-0002-3202-0343
Tsapras, Y.0000-0001-8411-351X
Batista, V.0000-0002-9782-0333
Beaulieu, J. P.0000-0003-0014-3354
Bode, M.0000-0001-7514-5560
Kane, S.0000-0002-7084-0529
Sahu, K. C.0000-0001-6008-1955
Steele, I.0000-0001-8397-5759
Ulaczyk, K.0000-0001-6364-408X
Additional Information:© 2009 RAS. Accepted 2009 February 9. Received 2009 February 9; in original form 2008 November 12. NK acknowledges STFC studentship PA/S/S/2006/04497 and an STFC travel grant covering his observing run at La Silla. We thank David Warren for financial support for the Mt Canopus Observatory. NK thanks Pascal Fouqué for organizing a workshop in Toulouse in 2007 November, and Joachim Wambsganss and Arnaud Cassan for their invitation to visit the Astronomisches Rechen-Institut in Heidelberg in 2008 April. We would like to thank the anonymous referee for helpful comments on the manuscript. We also thank the University of Tasmania for access to their TPAC supercomputer on which part of the calculations were carried out. PF expresses his gratitude to ESO for a two months invitation at Santiago headquarters, Chile, in 2008 October and November. The OGLE project is partially supported by the Polish MNiSW grant N20303032/4275.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)PA/S/S/2006/04497
Ministerstwo Nauki i Szkolnictwa Wyższego (MNiSW)N20303032/4275
Subject Keywords:gravitational lensing; methods: miscellaneous; binaries: general; planetary systems; Galaxy: bulge
Issue or Number:2
Record Number:CaltechAUTHORS:20090904-142928631
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15635
Deposited By: Ruth Sustaita
Deposited On:14 Sep 2009 16:36
Last Modified:09 Mar 2020 13:19

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