Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
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BINARY MICROLENSING EFFECTS I. CAUSTICS AND THE FLUX FACTOR K

  • LEE DONG WOOK (Dept. of Astronomy & Space Science, Kyunghee University) ;
  • CHANG KYONG AE (Dept. of Physics, Chongju University) ;
  • KIM SANG JOON (Dept. of Astronomy & Space Science, Kyunghee University)
  • Published : 1998.04.01
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Abstract

We have made semi-analytical studies to investigate the configurations of caustics and the probability distribution of the flux factor K for the binary microlensing including external shears. A parametric equation of critical curve is derived in a 4th order complex polynomial. We present the topological dependencies of the caustics for selected gamma parameters (0, 0.3, 0.6, 1.3, 2.0, and 2.5) and convergence terms (0., 0.4, 0.8, 1.2, 1.6, and 2.0). For the purpose of analyzing the efficiency of High Amplification Event (HAE) on each caustics, we examine the probability distribution of the flux factor by a Monte Carlo method. Changing the separation of the binary system from 0.8 to 1.3 (in normalied unit), we examine the probability distribution of the K-values in various gamma parameters. The relationship between gamma parameters, seperations and their probabilties of the flux factor K have been studied. Our results show that the relatively higher K values (K>1.5) are increased as increasing the separation of the binary system. We therfore conclude that, in the N-body microlensing, the probabilities of higher HAEs are inversely proportional to the star density as well. We also point out that the present research might be used as a preliminary step toward investigating heavy N-body microlensing simulations.

Keywords

References

  1. Proc. IAU Sympo. v.173 Astrophysical Applications of Gravitational Lensing Alard, C.;C. S. Kochanek(ed.);J. N. Hewitt(ed.)
  2. Nature v.365 Alock, C.;Akerlof, C. W.;Allsman. R. A.(et al)
  3. Nature v.365 Aubourg, E.;Bareyre, P.;Brehin, P.(et al)
  4. Ap.J v.195 Bourassa, R. R.;Kantowski, R.
  5. Nature v.279 Chang, K.;Refsdal, S.
  6. Ph. D thesis Chang, K.
  7. A & A v.130 Chang, K.
  8. A & A v.132 Chang, K.;Refsdal, S.
  9. A & A v.194 Grieger, B.;Kayser, R.;Refsdal, S.
  10. A & A v.221 Kayser, R.;Witt, H. J.
  11. Ap.J v.374 Mao, S.;Paczynski, B.
  12. Ap.J v.301 Paczynski, B.
  13. Proc. IAU Sympo. v.173 Astrophysical Applications of Gravitational Lensing Paczynski, B.;C. S. Kochanek(ed.);J. N. Hewitt(ed.)
  14. Numerical Recipes in C Press, W. H.;Tehkolsky, S. A.;Vettering, W. T.;Flannery, B. P.
  15. MNRAS v.128 Refsdal, S.
  16. A & A v.164 Schneider, P.;Weiss, A.
  17. Gravitational Lenses Schneider, P.;Ehlers, J.;Falco, E. E.
  18. Acta. A. v.42 Udalski, A.;Szymanski, M.;Kaluzny, J;Kubiak, M;Mateo, M
  19. A & A v.236 Witt, H. J.
  20. ApJ v.244 Young, P.