• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.78.3-78.3
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• 2017

The positions of galaxies in comoving Cartesian space varies under different cosmological parameter choices, inducing a redshift-dependent scaling in the galaxy distribution. The shape of the two-point correlation of galaxies exhibits a significant redshift evolution when the galaxy sample is analyzed under a cosmology differing from the true, simulated one. In our previous works, we can made use of this geometrical distortion to constrain the values of cosmological parameters governing the expansion history of the universe. This current work is a continuation of our previous works as a strategy to constrain cosmological parameters using redshift-invariant physical quantities. We now aim to understand the redshift evolution of the full shape of the small scale, anisotropic galaxy clustering and give a firmer theoretical footing to our previous works.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.48.3-48.3
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• 2017

In our recent investigation of the Oosterhoff dichotomy among globular clusters (GCs), we have shown that the RR Lyrae variables in the Oosterhoff groups I, II, and III are produced mostly by first, second, and third generation stars (G1, G2, and G3), respectively. Unlike GCs, RR Lyrae stars in the Local Group dwarf galaxies show Oosterhoff-intermediate characteristics. The origin of this, however, is yet to be understood. In this poster, we will present our progress in understanding the origin of this phenomenon.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.235-235
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• 2012

The "Widefield ASKAP L-band Legacy All-sky Blind surveY" (WALLABY) is an extragalactic HI survey which aims to examine HI properties and large-scale distribution of ~500,000 galaxies out to z ~ 0.27, covering a wide range of science goals associated with galaxy formation and evolution (P.I.: B. Koribalski & L. Staveley-Smith). The combination of ASKAP's exquisite column density sensitivity and a large primary beam will make it possible to systematically investigate the rarely explored low column-density HI in the universe. Ultimately, the largest and most homogeneous data set from WALLABY will drastically improve and broaden our knowledge on galaxy formation and evolution. ASKAP will be on-line in 2013, so to ensure timely and efficient reduction and analysis of the large WALLABY data set, we have been developing and testing reliable source finding tools and data analysis pipelines. In this talk I present recent progress of WALLABY, especially on the kinematic parameterisation pipeline for the spatially resolved galaxies detected by WALLABY.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.73.5-73.5
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• 2019

Studying the amount and kinematics of circumand intergalactic medium (CGM and IGM) is key to understanding the role of feedback and environment (cold streams and galactic winds) in the evolution of galaxies. In particular, $Ly{\alpha}$ emission line has been utilized to investigate the density structure and kinematics of the (most abundant) H I gas in the CGM and IGM around galaxies. Therefore, modeling $Ly{\alpha}$ radiative transfer through multiphase interstellar medium (ISM), CGM and IGM is crucial in understanding the galaxy evolution. As discussed in Kakiichi & Dijkstra (2018), most $Ly{\alpha}$ RT effects would occur on interstellar scales. This is because the main source of $Ly{\alpha}$ photons would be H II regions, which are in most cases, if not all, surrounded by "cold" photo-dissociation regions. However, most $Ly{\alpha}$ RT studies have been performed in the CGM and IGM environments with T ~ 10,000K. In this talk, we present how the $Ly{\alpha}$ RT effect in the cold ISM with T ~ 100 K regulates the $Ly{\alpha}$ spectral properties.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.73.1-73.1
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• 2019

We investigate the evolution of the galactic spin of spiral galaxies in various dynamical situations using the N-body/SPH simulations. To do this we first construct a Milky Way-like galaxy model. Then we perform both prograde and retrograde encounters between the spiral galaxy pair. We also conduct a simulation with our galaxy model in isolation for comparison. We find that the circular motion of the disk stars in the inner region of the galaxy decrease clearly when the galaxy experiences strong prograde interactions. Such decrease has not found when the galaxy experiences weak or no interactions. We compare our simulation results with recent observational studies on the galactic spins.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.118.2-118.2
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• 2014

As the most sensitive radio interferometer ever operated in millimeter/submillimeter, the ALMA has opened a new window on extragalactic astronomy. Its superior resolution and sensitivity allow the community to study the gas kinematics of distant galaxies as well as the molecular gas properties of nearby galaxies in GMC scale, already in its early commissioning stage. Also the ALMA provides a great tool to probe the dust contents of extragalactic sources at all redshifts, which is important in understanding of galaxy formation and evolution history over cosmic time. In this presentation, I will review the ALMA capabilities with the emphasis on the extragalactic science. I will also revisit some highlights from the early science and discuss future perspectives.

• Journal of The Korean Astronomical Society
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• v.34 no.4
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• pp.261-263
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• 2001

Numerical simulations based on the smoothed particle hydrodynamics (SPH) is performed to investigate the dynamical properties of barred galaxies that have nuclear rings. The nuclear ring morphology depends on the relative strength of bar potentials. Nuclear rings form between the two ILRs and align perpendicular to the bars unless the bar potentials are strong enough to allow the x1 orbits near the ILRs. Shock dissipation plays a critical role in the formation of nuclear rings.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.27.2-27.2
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• 2021

The unknown excess emission in the near-infrared is thought to be related to the evolution of galaxies in the early epoch of Universe. Due to its extremely faint brightness, it can be observed only in space. Many infrared space missions have been tried to trace the origin of the Cosmic Infrared Background through the measurement of its absolute brightness and its spatial fluctuation. In addition, the infrared observations can address questions ranging from the origin of first galaxies in the Universe to the formation of stars. I will overview the Korean infrared space missions and introduce the status of the recent international collaboration mission, SPHEREx.

• The Bulletin of The Korean Astronomical Society
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• v.33 no.1
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• pp.34.2-34.2
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• 2008

• Bulletin of the Korean Space Science Society
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• 1999.09a
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• pp.67-67
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• 1999

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