• 천문학회지
• /
• 제24권1호
• /
• pp.13-24
• /
• 1991

We construct a simple photometric evolution model of galaxies based on the evolutionary population synthesis. In our models an exponentially decreasing SFR with a power law IMF is used to compute the UBV colors of galaxies from ellipticals to late type spirals. It is shown that the integrated colors of galaxies with different Hubble type can be explained by one parameter, SFR.

• 한국초등과학교육학회지:초등과학교육
• /
• 제36권4호
• /
• pp.405-427
• /
• 2017

This study aims to describe various teaching cases about 'earth revolution' in terms of PCK; knowledge of curriculum, knowledge of teaching strategies and knowledge of assessment. Based on these various cases we suggested PCK progressions about 'earth revolution'. For these, we recorded 'solar system and star' classes of nine elementary school teachers' in Kangwon, Gyeonggi, Gwangju, and Seoul. We adopted Lee & Lee (2016)'s topic-specific PCK framework to analyze the classes. As results, we suggested topic-specific PCK progression about 'earth revolution'. The results showed the upper anchor of the earth revolution class were exploring the reason of the change of constellation, finding the tendency of constellation change. These teachings were carried by the teachers' adaptive strategies. The upper anchor of the assessment was monitoring students' understanding during the whole class. The PCK progression about 'earth revolution' could help the teachers plan the earth revolution class, and reflect their own teachings.

• 한국지구과학회지
• /
• 제36권5호
• /
• pp.427-436
• /
• 2015

We classified Abell clusters using the magnitude differences between two or three bright member galaxies and investigated how such classification was correlated with the properties of brightest cluster galaxies (BCGs). S-type BCGs being clearly brighter than the rest of the member galaxies were likely to be red, luminous, and evolved as early type galaxies. On the other hand, T-type BCGs being not dominant at all were less luminous than early type galaxies. A small fraction of BCGs was currently forming stars, and all of the star-forming BCGs were T-type BCGs. Active galactic nuclei were most frequent for S-type BCGs. Through these quantitative analyses of the BCG properties, we discussed the possible scenario of BCG formation and the differences between S-type and T-type of BCGs.

• 천문학논총
• /
• 제16권1호
• /
• pp.43-47
• /
• 2001

We developed a CCD camera that can observe wide fields on the sky. We tested the field of views using various lenses. For cooling the CCD chip, we used a thermoelectric cooling device and tested the cooling efficiency. This camera will continuously observe a part of the sky. The data from the camera will be used to decide the current weather condition by the real-time star counting program (SCount) which will be developed later.

• 천문학회보
• /
• 제39권2호
• /
• pp.53.2-53.2
• /
• 2014

Radial color gradient of early type galaxies (ETGs) is a key tool for studying the evolution of these galaxies. In this work, we investigated whether ETGs having negative or positive color gradients show any distinguishable characteristics in the galaxy properties. We selected sample of 211 ETGs at 0.01 < z < 0.5 in the Spitzer FLS field, then we constructed u-R color gradients. We obtained the stellar mass, specific star formation rate and fluxes of emission lines of each ETG from MPA-JHU DR7 catalog. Spitzer IRAC and MIPS 24 micron data were used to detect dust emission from the ETGs. Preliminary result shows that less massive galaxies are likely to have positive color gradients, which is probably due to the ongoing star formation in the galaxy core. Almost all AGNs have negative color gradients. This probably is because AGNs are located in relatively massive galaxies with little ongoing star formation. There exists a marginal difference in the percentage of galaxies with PAH emission between ETGs having positive color gradient and negative color gradient. This also supports that ETGs with positive color gradient are galaxies having enhanced star formation.

• 한국지구과학회지
• /
• 제30권1호
• /
• pp.69-80
• /
• 2009

본 연구에서는 SDSS DR6을 이용하여 별탄생율과 활동성 은하핵의 막대의 특성, 특히 막대의 세기에 대한 의존성을 조사하였다. 막대의 세기를 보다 잘 표현하기 위하여 막대의 길이와 축비를 이용하여 막대를 6개의 군으로 나누었다. $H{\alpha}$ 방출선 세기로부터 구한 별탄생율은 막대의 세기와 좋은 상관관계를 보였으나 활동성 은하핵은 막대와 또렷한 상관관계를 보이지 않았다. 전자의 상관관계는 막대에 의해 유발되는 가스 유입이 막대의 세기에 의존하기 때문이라고 해석되며, 활동성 은하핵이 막대의 특성과 특별한 상관관계를 보이지 않는 것은 초중량 블랙홀로 들어가는 가스의 양이 막대와 초거대 블랙홀과의 상호 작용에 의해 조절된다는 것을 의미한다. 활동성 은하핵은 주변의 밀도에 의해 영향을 받으나 별탄생율은 주변의 밀도와 무관해 보인다. 이것은 별탄생은 은하에서의 가스 밀도에 의해 결정되는 국지적인 현상인데 반해 활동성 은하핵은 질량이나 광도와 같은 은하의 특성이 밀도-광도관계로 표현되는 은하의 환경 의존성과 밀접한 관계가 있음을 암시한다.

• 한국지구과학회지
• /
• 제32권2호
• /
• pp.200-211
• /
• 2011

본 연구는 애니메이션 모듈을 활용한 수업이 학생들의 별의 일주운동 개념변화에 얼마나 효과적인지 알아보기 위한 것이다. 이를 위해 별의 일주운동을 학습하지 않은 학생 4명을 연구 대상으로 선정하였다. 애니메이션 모듈은 Flash MX를 사용하여 3차원적 공간개념을 이해하기 쉽게 개발하였다. 또한, 개별학습이 용이하도록 교사가 육성 녹음한 내용을 삽입하였고, 보충 학습자료를 제시하였다. 애니메이션 모듈은 태양계의 운동 단원으로 지구의 운동, 달의 운동, 행성의 운동으로 구성되었다. 애니메이션 모듈을 적용하기 전에 질문지와 면담을 통해 학생들의 별의 일주운동에 대한 선개념을 분석하였다. 애니메이션 모듈을 활용한 학습 후 사후 검사를 실시하고 사전 검사와 비교하여 개념 변화를 알아보았다. 그 결과, 중위도 방위별 별의 움직임을 제대로 표현하지 못한 3명의 학생은 모든 방향에 걸쳐 정확하게 나타냈다. 그리고 4명의 학생들이 별의 일주운동 모습이 모든 방향에서 직선 형태로 움직인다고 생각하였다. 또한, 중위도에서 별이 움직이는 각도가 직각으로 움직인다고 생각했던 4명의 학생 모두 비스듬하게 움직이는 것으로 개념이 변화하였다.

• 천문학회지
• /
• 제52권6호
• /
• pp.235-244
• /
• 2019

We present the results of near-infrared imaging observations of the galaxy overdensity around the z = 1.44 radio-loud active galactic nucleus (AGN) 6CE1100+3505, which was carried out with the purpose of sampling the redshifted Hα emission from the actively star-forming galaxies that could constitute the overdensity. The existence of the structure around this AGN was spectroscopically confirmed by previous grism observations which are however limited to the central region. Using the CH4Off narrow/medium-band and H broad band filters in the Wide Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT), we constructed a sample of objects that show a flux excess in the CH4Off band due to line emission. The emission line flux is ~ 4.9 × 10^-16 erg s^-1 cm^-2, corresponding to a star formation rate (SFR) of ~ 50 M_⊙ yr^-1 for galaxies at redshifts z ~ 1.4. None of the galaxies with medium-band flux excess is located within 1 Mpc from the central AGN, and there is no evidence that the selected galaxies are associated with the proposed cluster. Along with the star formation quenching near the center that was found from the previous grism observations, the lack of extreme starbursts in the structure suggests that at z ~ 1.4, overdense regions are no longer favorable locations for vigorous star formation.

• 천문학논총
• /
• 제32권1호
• /
• pp.1-4
• /
• 2017

Some after-dinner thoughts on the giants of infrared space astronomy. I here describe important events in infrared astronomy starting from 1964 when I started working on my PhD. Here I describe how I became involved in IRAS, Infrared Space Observatrory (ISO), Herschel, Spitzer and AKARI, together with important events that led to these great missions.

• 한국초등과학교육학회지:초등과학교육
• /
• 제34권3호
• /
• pp.288-296
• /
• 2015

This study aimed to analysis of concepts and inquiry activities related to the 'Earth Science' area in the South Korean elementary school textbooks to the current and to seek the improvement of future textbook. For the study, we were collected South Korean elementary school textbooks to the current. After the collection had been made, we were analyzed related to the 'Earth' area in the South Korean elementary school textbooks and were extracted central concepts and inquiry activities. The result of this study: First, there were 'A change in the land', 'Strata and Fossil', 'Volcanoes and Earthquakes', 'Earth and Moon', 'The weather', 'The Solar system and the Star', and 'Seasonal Change' in the central concepts related to the 'Earth' area in the South Korean elementary school textbooks to the current. Second, central concepts were almost the same but the curriculum was changed. Third, inquiry activities also were confirmed to be maintained with little change. This result was believed that it can provide a variety of suggestions at this point in changing the curriculum.