A systematic fitting scheme for caustic-crossing microlensing events

  1. N. Kains1,2,*,
  2. A. Cassan1,3,
  3. K. Horne1,2,
  4. M. D. Albrow1,4,
  5. S. Dieters1,5,
  6. P. Fouqué1,6,
  7. J. Greenhill1,7,
  8. A. Udalski8,9,
  9. M. Zub1,3,†,
  10. D. P. Bennett1,10,
  11. M. Dominik2,‡,
  12. J. Donatowicz1,11,
  13. D. Kubas1,12,
  14. Y. Tsapras1,13,
  15. T. Anguita3,
  16. V. Batista1,5,
  17. J.-P. Beaulieu1,5,
  18. S. Brillant1,12,
  19. M. Bode1,13,
  20. D. M. Bramich1,14,
  21. M. Burgdorf1,13,
  22. J. A. R. Caldwell1,15,
  23. K. H. Cook1,16,
  24. Ch. Coutures1,17,
  25. D. Dominis Prester1,18,
  26. U. G. Jørgensen1,19,
  27. S. Kane1,20,
  28. J. B. Marquette1,5,
  29. R. Martin1,21,
  30. J. Menzies1,22,
  31. K. R. Pollard1,4,
  32. N. Rattenbury1,23,
  33. K. C. Sahu1,24,
  34. C. Snodgrass1,12,
  35. I. Steele1,11,
  36. C. Vinter1,19,
  37. J. Wambsganss1,3,
  38. A. Williams1,21,
  39. M. Kubiak8,9,
  40. G. Pietrzyński8,9,25,
  41. I. Soszyński8,9,
  42. O. Szewczyk8,9,25,
  43. M. K. Szymański8,9,
  44. K. Ulaczyk8,9,
  45. Ł. Wyrzykowski13,26

Article first published online: 8 APR 2009

DOI: 10.1111/j.1365-2966.2009.14615.x

Issue

Monthly Notices of the Royal Astronomical Society

Monthly Notices of the Royal Astronomical Society

Volume 395, Issue 2, pages 787–796, May 2009

Additional Information

How to Cite

Kains, N., Cassan, A., Horne, K., Albrow, M. D., Dieters, S., Fouqué, P., Greenhill, J., Udalski, A., Zub, M., Bennett, D. P., Dominik, M., Donatowicz, J., Kubas, D., Tsapras, Y., Anguita, T., Batista, V., Beaulieu, J.-P., Brillant, S., Bode, M., Bramich, D. M., Burgdorf, M., Caldwell, J. A. R., Cook, K. H., Coutures, C., Dominis Prester, D., Jørgensen, U. G., Kane, S., Marquette, J. B., Martin, R., Menzies, J., Pollard, K. R., Rattenbury, N., Sahu, K. C., Snodgrass, C., Steele, I., Vinter, C., Wambsganss, J., Williams, A., Kubiak, M., Pietrzyński, G., Soszyński, I., Szewczyk, O., Szymański, M. K., Ulaczyk, K. and Wyrzykowski, Ł. (2009), A systematic fitting scheme for caustic-crossing microlensing events. Monthly Notices of the Royal Astronomical Society, 395: 787–796. doi: 10.1111/j.1365-2966.2009.14615.x

Author Information

  1. 1

    PLANET/RoboNet Collaborations

  2. 2

    SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St Andrews KY16 9SS

  3. 3

    Astronomisches Rechen-Institut (ARI), Zentrum für Astronomie (ZAH), Heidelberg University, Mönchhofstraße 12-14, 69120 Heidelberg, Germany

  4. 4

    Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch, New Zealand

  5. 5

    Institut d'Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie, 98bis Boulevard Arago, 75014 Paris, France

  6. 6

    LATT, Université de Toulouse, CNRS, 14 avenue Edouard Belin, F-31400 Toulouse, France

  7. 7

    School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, Tasmania 7001, Australia

  8. 8

    Optical Gravitational Lens Experiment (OGLE) Collaboration

  9. 9

    Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

  10. 10

    Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556, USA

  11. 11

    Department of Computing, Technical University of Vienna, Wiedner Hauptstr. 10, Vienna A-1040, Austria

  12. 12

    European Southern Observatory, Casilla 19001, Vitacura 19, Santiago, Chile

  13. 13

    Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD

  14. 14

    Isaac Newton Group of Telescopes, Apartado de Correos 321, E-38700 Santa Cruz de La Palma, Spain

  15. 15

    McDonald Observatory, 16120 St Hwy Spur 78, Fort Davis, TX 79734, USA

  16. 16

    Lawrence Livermore National Laboratory, IGPP, PO Box 808, Livermore, CA 94551, USA

  17. 17

    DSM/DAPNIA, CEA Saclay, 91191 Gif-sur-Yvette cedex, France

  18. 18

    Physics Department, Faculty of Arts and Sciences, University of Rijeka, 51000 Rijeka, Croatia

  19. 19

    Niels Bohr Institute, Astronomical Observatory, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark

  20. 20

    NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125, USA

  21. 21

    Perth Observatory, Walnut Road, Bickley, Perth 6076, Australia

  22. 22

    South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa

  23. 23

    Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL

  24. 24

    Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA

  25. 25

    Departamento de Fisica, Astronomy Group, Universidad de Concepción, Casilla 160-C, Concepción, Chile

  26. 26

    Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA

  1. †

    Member of International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg.

  2. ‡

    Royal Society University Research Fellow.

* E-mail: nk87@st-and.ac.uk

Publication History

  1. Issue published online: 24 APR 2009
  2. Article first published online: 8 APR 2009
  3. Accepted 2009 February 9. Received 2009 February 9; in original form 2008 November 12

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Keywords:

  • gravitational lensing;
  • methods: miscellaneous;
  • binaries: general;
  • planetary systems;
  • Galaxy: bulge

ABSTRACT

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.

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