• The Bulletin of The Korean Astronomical Society
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• v.25 no.1
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• pp.47-47
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• 2000

• The Bulletin of The Korean Astronomical Society
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• v.31 no.1
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• pp.55.1-55.1
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• 2006

• Bulletin of the Korean Space Science Society
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• 1999.09a
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• pp.36-36
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• 1999

No Abstract, See Full Text

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.221-222
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• 2012

We present the results of far-infrared spectral mapping of the Galactic center region with FIS-FTS, which covered the two massive star-forming clusters, Arches and Quintuplet. We find that two dust components with temperatures of about 20 K and 50 K are required to fit the overall continuum spectra. The warm dust emission is spatially correlated with the [OIII] $88{\mu}m$ emission and both are likely to be associated with the two clusters, while the cool dust emission is more widely distributed without any clear spatial correlation with the clusters. We find differences in the properties of the ISM around the two clusters, suggesting that the star-forming activity of the Arches cluster is at an earlier stage than that of the Quintuplet cluster.

• Publications of The Korean Astronomical Society
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• v.16 no.1
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• pp.15-20
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• 2001

We observed the thermal transitions of SiO (J=I-0, 2-1) and $^{29}SiO$ (J=l-O) toward the Sgr A molecular clouds. The distribution and the velocity structure of SiO are very similar to previous results for 'quiet' interstellar molecules. We think· that the SiO has been well mixed with other molecules such as $H_2$ which may indicate that the formation of Sgr A molecular clouds was affected by the activities, such as shock waves or energetic photons, from the Galactic center in large scales. The total column density of SiO is about $4.1\times10^{14} cm^{-2}$ and the fractional abundance $SiO/H_2$ appears to be about 10 times larger than those of other clouds in the central region of our galaxy. The derived values are thought to be lower limits since the optical depths of the observed SiO lines are not very thin. The formation of SiO has been known to be critically related to shocks, and our results provide informative data on the environment of our Galactic center.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.39.1-39.1
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• 2016

We report the discovery of a kiloparsec-size supershell in the outskirts of the Milky Way with the compact high-velocity cloud, HVC 040+01-282 (hereafter, CHVC040), at its geometrical center using the "Inner-Galaxy Arecibo L-band Feed Array" HI 21 cm survey data. Supershells are large gaseous shells, which could be produced by one of most energetic activities with an explosion energy more than $3{\times}1052erg$. The most promising origin is the explosion of multiple supernovae in OB associations, or alternatively, the impact of HVCs falling into the Galactic disk. We found the association between CHVC040 and the Galactic supershell by analysis of their morphological and physical properties. Our results imply that some compact HVCs can survive their trip through the Galactic halo and inject energy and momentum into the Milky Way disk.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.173-174
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• 1996

We have mapped $17 deg^2$ region toward Galactic anticenter in $^{12}CO$ J = 1 - 0 using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory (TRAO). The region mapped in this paper is the first target of the Galactic AntiCenter CO Survey Project (GACCOS) and was selected comparing with IRAS Sky Survey Atlas (ISSA) images at 100${\mu}m$. Molecular emission of the target area is found to be very extended and is well matching with the FIR emission boundary. There are several pieces of clouds, and as some of spectra show several peaks, there seem to be several clouds overlapped in some directions. The Velocity of Local Standard of Rest ($V_{LSR}$) of the CO emission of the mapped region ranges from -20 to +10 km/s. It is also found that the two cloudlets located around I = $180^{\circ}$ have $V_{LSR}$ = -20 km/s, which is very abnormal. The peak antenna temperature of 13 K arises near the H II Region S241.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.249-255
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• 2004

Here we present a linear stability analysis and an MHD 2D model for the Parker-Jeans instability in the Galactic gaseous disk. The magnetic field is assumed parallel to a Galactic spiral arm, and the gaseous disk is modelled as a multi-component, magnetized, and isothermal gas layer. The model employs the observed vertical stratifications for the gas density and the gravitational acceleration in the Solar neighborhood, and the self-gravity of the gas is also included. By solving Poisson's equation for the gas density stratification, we determine the vertical acceleration due to self-gravity as a function of z. Subtracting it from the observed gravitational acceleration, we separate the total acceleration into self and external gravities. The linear stability analysis provides the corresponding dispersion relations. The time and length scales of the fastest growing mode of the Parker-Jeans instability are about 40 Myr and 3.3 kpc, respectively. In order to confirm the linear stability analysis, we have performed two-dimensional MHD simulations. These show that the Parker-Jeans instability under the self and external gravities evolves into a quasi-equilibrium state, creating condensations on the northern and southern sides of the plane, in an alternate manner.

• The Bulletin of The Korean Astronomical Society
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• v.34 no.2
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• pp.48.1-48.1
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• 2009

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.237-242
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• 2012

We have performed a systematic study of interstellar dust grains in various environments of galaxies. AKARI has revealed the detailed properties of dust grains not only in star-forming regions but also in regions not relevant to star formation, some of which are found not to follow our old empirical knowledge. Because of its unique capabilities, AKARI has provided new knowledge on the processing of large grains and polycyclic aromatic hydrocarbons (PAHs). For example, we detect PAHs from elliptical galaxies, which show unusual spectral features and spatial distributions, demonstrating importance of material processing in the interstellar space. We find that copious amounts of large grains and PAHs are flowing out of starburst galaxies by galactic superwinds, which are being shattered and destroyed in galactic haloes. We discover evidence for graphitization of carbonaceous grains near the center of our Galaxy, providing a clue to understanding the activity of the Galactic center. We review the results obtained from our AKARI program, focusing on the processing of carbonaceous grains in various environments of galaxies.