Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
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A CHARACTERISTIC PLANETARY FEATURE IN CAUSTIC-CROSSING HIGH-MAGNIFICATION MICROLENSING EVENTS

  • Kim, Do-Eon (Program of Brain Korea 21, Department of Physics, Chungbuk National University) ;
  • Han, Cheong-Ho (Program of Brain Korea 21, Department of Physics, Chungbuk National University)
  • Published : 2009.06.30
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Abstract

We propose a diagnostic that can resolve the planet/binary degeneracy of central perturbations in caustic-crossing high-magnification microlensing events. The diagnostic is based on the difference in the morphology of perturbation inside the central caustics induced by a planet and a wide-separation binary companion. We find that the contours of excess exhibit a concentric circular pattern around the caustic center for the binary-lensing case, while the contours are elongated or off-centered for the planetary case. This difference results in the distinctive features of the individual lens populations in the residual of the trough region between the two peaks of the caustic crossings, where the shape of the residual is symmetric for binary lensing while it tends to be asymmetric for planetary lensing. We determine the ranges of the planetary parameters for which the proposed diagnostic can be used. The diagnostic is complementary to previously proposed diagnostics in the sense that it is applicable to caustic-crossing events with small finite-source effect.

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References

  1. Beaulieu, J.-P., et al., 2006, Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing, Nature, 439, 437 https://doi.org/10.1038/nature04441
  2. Bennett, D. P., et al., 2008, A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192, ApJ, 684, 663 https://doi.org/10.1086/589940
  3. Bond, I. A., et al., 2002, Study by MOA of extrasolar planets in gravitational microlensing events of high magnification, MNRAS, 333, 71 https://doi.org/10.1046/j.1365-8711.2002.05380.x
  4. Bond, I. A., et al., 2004, OGLE 2003-BLG-235/MOA 2003-BLG-53: A Planetary Microlensing Event, ApJ, 606, L155 https://doi.org/10.1086/420928
  5. Chung, S., et al., 2005, Properties of Central Caustics in Planetary Microlensing, ApJ, 630, 535 https://doi.org/10.1086/432048
  6. Dong, S., et al., 2006, Planetary Detection Efficiency of the Magnification 3000 Microlensing Event OGLE-2004-BLG-343, ApJ, 642, 842 https://doi.org/10.1086/501224
  7. Dong, S., et al., 2008, Microlensing Event MOA- 2007-BLG-400: Exhuming the Buried Signature of a Cool, Jovian-Mass Planet, ApJ, submitted (arXiv:0809.2997)
  8. Gaudi, B. S., et al., 2008, Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing, Science, 319, 927 https://doi.org/10.1126/science.1151947
  9. Gould, A., et al., 2006, Microlens OGLE-2005-BLG-169 Implies That Cool Neptune-like Planets Are Common, ApJ, 644, L37 https://doi.org/10.1086/505421
  10. Han, C., 2009a, Distinguishing Between Planetary and Binary Interpretations of Microlensing Central Perturbations Under the Severe Finite-Source Effect, ApJ, 691, 9 https://doi.org/10.1088/0004-637X/691/1/L9
  11. Han, C., 2009b, Microlensing Zone of Planets Detectable Through the Channel of High-Magnification Events, ApJ, 691, 452 https://doi.org/10.1088/0004-637X/691/1/452
  12. Han, C. & Gaudi, B. S., 2008, A Characteristic Planetary Feature in Double-Peaked, High-Magnification Microlensing Events, ApJ, 689, 53 https://doi.org/10.1086/592723
  13. Han, C., Gaudi, B. S., An, J. H., & Gould, A., 2005, Microlensing Detection and Characterization of Wide- Separation Planets, ApJ, 618, 962 https://doi.org/10.1086/426115
  14. Kubas, D., et al., 2008, Limits on additional planetary companions to OGLE 2005-BLG-390L, A&A, 483, 317 https://doi.org/10.1051/0004-6361:20077449
  15. Udalski, A., et al., 2005, INTEGRAL IGR J18135-1751 = HESS J1813-178: A New Cosmic High-Energy Accelerator from keV to TeV Energies, ApJ, 629, L109 https://doi.org/10.1086/447766
  16. Udalski, A., et al., 2008, The Optical Gravitational Lensing Experiment. Final Reductions of the OGLEIII Data, Acta Astronomica, 58, 69