Stellar Contribution to the Galactic Bulge Microlensing Optical Depth
- Cheongho Han, A. Gould
- Physics
- 13 March 2003
We estimate the optical depth to self-lensing by stars in the Galactic bulge using the Hubble Space Telescope star counts of Holtzman et al. and Zoccali et al. as extrapolated by Gould into the brown…
The Mass Spectrum Of Machos From Parallax Measurements
- Cheongho Han, A. Gould
- Physics
- 14 September 1994
We demonstrate that by making satellite-based parallax measurements of Macho events, it is possible to distinguish disk from bulge Machos and to determine individual masses of disk Machos to an…
Statistical Determination of the MACHO Mass Spectrum
- Cheongho Han, A. Gould
- Physics
- 22 April 1995
The mass function of 51 Massive Compact Objects (MACHOs) detected toward the Galactic bulge is statistically estimated from Einstein ring crossing times $t_{\rm e}$. For a Gaussian mass function, the…
Properties of Planetary Caustics in Gravitational Microlensing
- Cheongho Han
- Physics, Geology
- 7 October 2005
Although some of the properties of the caustics in planetary microlensing have been known, our understanding of them is mostly from scattered information based on numerical approaches. In this paper,…
On the Feasibility of Detecting Satellites of Extrasolar Planets via Microlensing
- Cheongho Han, W. Han
- Geology, Physics
- 17 July 2002
Although many methods of detecting extrasolar planets have been proposed and successful implementation of some of these methods enabled a rapidly increasing number of exoplanet detections, little has…
KMTNET: A NETWORK OF 1.6 M WIDE-FIELD OPTICAL TELESCOPES INSTALLED AT THREE SOUTHERN OBSERVATORIES
- Seung-Lee Kim, Chung-Uk Lee, I. Yuk
- Physics
- 29 February 2016
The Korea Microlensing Telescope Network (KMTNet) is a wide-field photometric system installed by the Korea Astronomy and Space Science Institute (KASI). Here, we present the overall technical…
Microlensing Detections of Moons of Exoplanets
- Cheongho Han
- Physics, Geology
- 17 May 2008
We investigate the characteristic of microlensing signals of Earth-like moons orbiting ice-giant planets. From this, we find that nonnegligible satellite signals occur when the planet-moon separation…
Statistics of Microlensing Optical Depth
- Cheongho Han, A. Gould
- Physics
- 18 October 1994
We show that the statistical error, $\sigma_{\tau}$, in estimating the optical depth, $\tau$, due to microlensing is substantially higher than the naive Poisson estimate: $\sigma_{\tau} = \sqrt{\eta…
Pixel Lensing Experiment Toward the M31 Bulge
- Cheongho Han
- Physics
- 1 November 1995
I demonstrate that one can detect pixel gravitational microlensing events at the rate ∼ 180 events yr-1 and that some fraction of events (∼ 15) will be good enough to measure timescales at the 20%…
Effects of Gas on Formation and Evolution of Stellar Bars and Nuclear Rings in Disk Galaxies
- W. Seo, Woong-Tae Kim, S. Kwak, P. Hsieh, Cheongho Han, P. Hopkins
- PhysicsAstrophysical Journal
- 7 January 2019
We run self-consistent simulations of Milky Way-sized, isolated disk galaxies to study the formation and evolution of a stellar bar as well as a nuclear ring in the presence of gas. We consider two…
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