• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.120.2-120.2
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• 2011

최근 북반구 하늘에 대한 SDSS 관측으로부터 우리은하 주변에서 다수 발견된 Ultra-Faint Dwarf Galaxies (uFDs)는 우주의 차가운 암흑물질 (CDM) 이론에서 예측한 질량이 작은 위성은하의 후보로 알려져 있다. 특히 이 uFDs는 역학적 특성과 관련하여 특이한 특징을 갖는 것으로 알려져 있다. 그러나 아직 그 수가 충분하지 않아 더 많은 수의 uFDs의 발견이 기대되고 있다. 이 연구에서는 남반구에서 가동이 시작된 남반구 전천 탐사 망원경 SkyMapper와 향후 가동하게 될 KMT-Net를 이용하여 남반구 하늘에서 SDSS 보다 더 1~2 등급 깊은 관측을 수행하여 다수의 더 어두운 uFDs를 탐색하고, 그 은하와 CDM의 특성을 연구함으로써 우리은하뿐만 아니라 우주의 구조와 진화에서의 CDM의 역할을 규명하는 프로젝트를 제안하려한다. 이 연구에서는 SkyMapper와 KMT-Net의 상호 역할, 관측전략, 기대효과 등 제반사항을 논의하려 한다.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.149.1-149.1
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• 2011

보현산 천문대의 근적외선 카메라시스템인 KASINICS(KASI Near Infrared Camera System)를 사용하여 다주기 변광성 BL Cam을 관측하였다. BL Cam(${\alpha}=03^h47^m19^s$, ${\delta}=+63^{\circ}22'7"$[J2000.0], V=13.10, ${\Delta}V$=0.33mag)은 광학적 쌍성으로 SX Pheoenics 변광성 중 하나이며 0.03 - 0.08day의 짧은 주기를 갖는 다주기 변광성으로 알려져 있다. 대상 천체의 적외선 관측을 위하여 한국천문연구원에서 개발한 지상 망원경용 근적외선 카메라 시스템 KASINICS를 사용해 J, H, Ks filter로 시계열 관측을 하였다. 대상 천체의 가시광 파장대에서의 관측 자료와 적외선 파장대에서의 관측 자료를 비교 분석함으로써 천체의 외곽층에서 발생하는 상호작용에 대해 알아볼 수 있다.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.116.2-116.2
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• 2011

We investigate Faraday rotation measure (RM) toward high Galactic latitudes due to the Galactic magnetic field (GMF). The Galactic contribution to RM comes from the global component and the turbulent component of the GMF, and we newly model the latter by incorporating data of MHD turbulence simulations. We find that for the turbulent velocity of ~50 km/s, the standard deviation of the RM due to the GMF toward high Galactic latitudes is close to the observed value, several rad m^{-2}. Yet, the predicted second-order structure function (SF) has values substantially smaller than the observed ones at separation angles of <~ several degree. This suggests that the intergalactic magnetic field (IGMF) significantly contributes to RM toward high Galactic latitudes, particularly at small angular scales. Our work proposes a strategy for surveys to explore the IGMF with LOFAR, ASKAP, MeerKAT, and SKA.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.104.2-104.2
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• 2011

We study X-ray characteristics of shocked ambient gas of the Galactic core-collapse supernova remnant Cas A. Using 1 Msec observation with Chandra X-ray Observatory, we identify thermal emissions from the shocked ambient gas along the outer boundary of the remnant. Our results show that Cas A is expanding into a circumstellar wind with a wind density n ~ 1 $cm^{-3}$ at the current outer radius of the remnant (~ 3 pc). We suggest that the progenitor star of Cas A, which exploded as a Type~IIb SN, had an initial mass ~16 Msun, and have lost ~10 Msun as a RSG wind. We discuss the implications of our results for the mass loss of massive stars and the resulting supernova type.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.101.1-101.1
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• 2011

National Meteorological Satellite Center(NMSC) of Korea Meteorological Administration(KMA) is collecting GNSS data in near-real time for about 80 GNSS stations operated by multiple agencies. (eg. National Geographic Information Institute (NGII), Korea Astronomy and Space Science Institute (KASI), DGNSS Central Office) Using these GNSS data, NMSC developed automatic Total Electron Contents(TEC) derivation system over the Korean peninsular every 1-hour based on single station data processing. We present the TEC result and validation of TEC using International GNSS Service(IGS) global TEC data for the case of quiet time and storm time. The future plans for the system improvement will be discussed.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2005.10a
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• pp.547-559
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• 2005

본 연구는 혁신목적과 사회적 자본간의 관계를 탐색적으로 고찰하친 있다. 기업의 혁신목적 유형에 따라 사회적 자본의 특성이 다르게 나타나는가를 분석한다. 이를 검증하기 위해 본 연구에서는 2005년 6월에서 7월 사이에 실시된 $\ulcorner$경북 IT기업 기술혁신활동 조사$\lrcorner$ 에서 나타난 176개 기업자료를 실증적으로 분석하였다. 분석은 IT기업의 기술혁신 유형변수로 '탐색형 기업', '활용형 기업'으로 구분하였고, 사회적 자본은 네트워크의 범위를 나타내는 '구조적 변수'와 강도를 나타내는 '관계적 변수'로 구분하여 구성형태를 분석하였다. 분석 결과, 탐색형 기업에서는 네트워크의 범위가 넓고(sparse network) 약한 연계(weak tie) 관계를 가지는 반면, 활용형 기업에서는 네트워크가 범위를 좁고(dense network) 강한 연계(strong tie) 관계를 가지는 것으로 나타났다.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.37.1-37.1
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• 2009

Solar type II radio burst is regarded as a signature of coronal shock. However its association with coronal mass ejections (CMEs)-driven shock and/or flare blast waves remains controversial. On December 31 2007, SOHO/LASCO and STEREO/COR observed a CME that occurred on the east limb of the Sun. Meanwhile, two type II bursts were observed sequently by KASI/E-Callisto and the Culgoora radio observatory during the CME apparence time. In this study, we estimate kinematics of the two coronal shocks from dynamic spectrum of the multiple type II bursts and compare with the kinematics of the CME derived from the space observations. An origin of the multiple type II bursts is inspected and discussed briefly.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.42.1-42.1
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• 2014

A gravitational weak-lensing map provides a weighted "picture" of the projected surface mass density and is to be an important tool for identifying "mass-selected" clusters of galaxies. However, weak-lensing maps have a limitation due to the projection of large-sclae structure along the line-of-sight. Geller et al. (2010) and Kurtz et al. (2012) compared massive clusters identified in a dense redshift survey with significant weak-lensing map convergence peaks. Both assessments of the efficiency of weak-lensing map for cluster identification did not draw a general conclusion, because the sample is so small. Thus, we additionally perform deep imaging observations of fields in a dense galaxy redshift survey that contain galaxy clusters at z~0.2-0.5, using CFHT Megacam. Our study will provide an important opportunity to examine the efficiency and completeness of a weak-lensing selection, and further to improve the method of cluster identification in future weak-lensing surveys.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.58.1-58.1
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• 2016

K-GMT Science Program, operated by Center for Large Telescopes (CfLAT) in Korea Astronomy and Space Science Institute (KASI), aims to promote the scientific researches by providing the access to the observational facilities such as 4-8m class telescopes and specialized instruments. In 2016, we plan to make various instruments with MMT and Gemini Observatory as well as IGRINS with 2.7m HJS Telescope in McDonald Observatory available to Korean Astronomical Community. We will present the current status and future prospect as well as some early results made from the K-GMT Science Program in past years.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.81.1-81.1
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• 2016

A total solar eclipse occurs on March 9 along the path through Indonesia and the Pacific. KASI organized an expedition team for total solar eclipse observation. The main purpose of this observation is to test the coronal temperature and outflow velocity diagnostics based on filter observation, which is proposed for the next generation coronagraph. In addition, various white light observations including automatic programmed observation, manual observation, linear polarization, and time-lapse movie will be tried. We report the preliminary result of the expedition.