• Title/Summary/Keyword: gravitational microlensing

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Gravitational Microlensing Astrophysics

  • Han, Cheongho
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.29.1-29.1
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    • 2016

  • I introduce the field of gravitational microlensing that I have worked on for more than 2 decades. I describe how microlensing can be applied to various fields in astrophysics including dark matter, Galactic structure, binary objects, and extrasolar planets and present my scientific achievements in the individual fields. I start with a description of basic microlensing physics and state how microlensing can be applied to various fields. Finally, I briefly describe ongoing efforts and future projects in microlensing.

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GRAVITATIONAL MICROLENSING (미시중력렌즈)

  • Park Myeong-Gu;Han Cheongho
    • Journal of The Korean Astronomical Society
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    • v.34 no.2
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    • pp.81-97
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    • 2001

  • Since the first proposal by Paczynski, great efforts to detect Galactic dark matter by detecting light variations of stars located in the Magellanic Clouds and Galactic bulge caused by gravitational microlensing have been and are being carried out and more than 1,000 events have been successfully detected. In this paper, we review the progress in the theoretical and experimental progresses in microlensing. We begin with basics of microlensing and summarize the results obtained from the last 8 year observations along with the implications of the results. We also discuss the usefulness of microlensing in other fields of astronomy such as the stellar atmosphere, Galactic binary systems, and extra-solar planets. We finally discuss the problems of the current experiments and the new types of observations that can overcome these problems.

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DETECTION LEVEL ENHANCEMENTS OF GRAVITATIONAL MICROLENSING EVENTS FROM LIGHT CURVES: THE SIMULATIONS

  • IBRAHIM, ICHSAN;MALASAN, HAKIM L.;DJAMAL, MITRA;KUNJAYA, CHATIEF;JELANI, ANTON TIMUR;PUTRI, GERHANA PUANNANDRA
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.235-236
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    • 2015

  • Microlensing can be seen as a version of strong gravitation lensing where the separation angle of the image formed by light deflection by a massive object is too small to be seen by a ground based optical telescope. As a result, what can be observed is the change in light intensity as function of time; the light curve. Conventionally, the intensity of the source is expressed in magnitudes, which uses a logarithmic function of the apparent flux, known as the Pogson formulae. In this work, we compare the magnitudes from the Pogson formulae with magnitudes from the Asinh formulae (Lupton et al. 1999). We found for small fluxes, Asinh magnitudes give smaller deviations, about 0.01 magnitudes smalller than Pogson magnitudes. This result is expected to give significant improvement in detection level of microlensing light curves.

  • https://doi.org/10.5303/PKAS.2015.30.2.235 인용 PDF KSCI