• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.29.2-29.2
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• 2009

During the last four years, we have performed Sejong/ARCSEC Ca uvby survey using the CTIO-1m telescope aimed at obtaining Ca uvby photometry for about 50 globular clusters and selected fields in Baade's Windows. Our results show that Ca uvby photometric system can provide a powerful method to probe multiple populations in Galactic globular clusters. We will discuss the multiple stellar population in the globular cluster NGC6218 and NGC6752 as illustrations.

• 천문학회지
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• 제38권3호
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• pp.357-363
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• 2005

A deep stellar analysis is introduced for the poorly studied open cluster NGC 2509. The Near-IR database of the digital Two Micron All Sky Survey (2MASS) has been used to re-estimate and refine the fundamental parameters of the cluster, i.e. age, reddening, distance, and diameter. As well as, luminosity function, mass function, total mass, relaxation time, and mass segregation of NGC 2509 have been estimated here for the first time..

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2004년도 정기총회 및 제6최 특별 심포지움
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• pp.157-179
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• 2004

The application of magnetic method for archaeoprospection has been carried out through two archaeological areas in Egypt, Abydos and Abu Sir, In order to find out tile ancient Egyptian archaeological features. The magnetic work at the selected archaeological site of Abydos area was carried out by gradiometer survey, while magnetic work at the selected archaeological site of Abu Sir area was carried out by gradiometer survey and magnetic susceptibility measurements. A gradiometer survey with raster of 0.5 m/0.5 m has been carried out on a surface area of $9600 m^2$ at Abydos area to relocate the buried Solar Boats. The magnetic data were processed using Geoplot software to treat the field noises and enhance the quality of the obtained images. The final magnetic images indicate the existence of 12 Solar Boats as well as tombs, remains of ancient rooms and walls. All of them are expected to belong to the Middle Kingdom, particularly from the 18th to 20th Dynasties. Two magnetic tools have been applied over a selected site of $25600 m^2$ at Abu Sir area in order to detect the hidden archaeological features nearby the Sun Temple. The acquisition of the magnetic data was initiated by the measurements of the topsoil magnetic susceptibility of 272 samples collected from the whole studied area, and then followed by the gradiometer survey to measure tile vertical gradient of the geomagnetic field over an area of $14400 m^2$. The magnetic susceptibility results show the presence of high concentration at the middle part of the study area with a little extension to the south western side, with maximum value of about $36{\times}10^5$ SI. They may indicate the proximity of ritual monuments. Also, they offered the site of interest for carrying out a gradiometer survey. The gradiometer results show tile existence of numerous distributed archaeological features made of mud-bricks with different shapes and sizes. They may indicate tombs, burial rooms, dissected walls; all of them are expected to belong to the 5th Dynasty of pharaohs, who used to build their buildings by mud bricks. The depth of the expected buried archaeological features has been estimated from tihe gradiometer. It is around 1.2m for deep features and 0.42 m for shallow features.

• 우주기술과 응용
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• 제1권2호
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• pp.178-198
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• 2021

국내 태양우주환경 분야에서 널리 이용되는 자료와 모델의 이해와 활용도를 높이고, 세부 분야 간 공동연구의 기회의 장을 마련하고자, 최근 한국우주과학회 태양우주환경분과에서 국내 연구소와 대학을 중심으로 사용되는 태양우주환경 자료와 모델의 보유 및 활용에 대한 조사를 실시했다. 조사 결과를 크게 태양 및 행성간 공간, 자기권, 전리권의 세 분야로 나눠 정리하였고, 본 논문에서는 자기권 분야의 관련 자료와 모델을 소개한다. 자기권 연구의 특성 상 우주공간에서 지점관측을 위한 위성 개발과 운용에 투자가 많이 필요하여 국내 보유 자료는 다른 분야에 비해 상대적으로 적은 편으로 조사됐지만, 국내 지자기관측소를 통한 자기장 변화를 실시간으로 제공하고 있으며, 자기권 모델을 통해 꾸준한 연구를 수행 중이다. 본 논문에서는 자기권 분야 중 국내 위성자료를 이용한 연구들과 제 1원리 물리법칙에 바탕이 된 모델을 대표로 소개한다. 이번 조사 결과와 이를 정리한 논문이 우주과학 관련 자료에 대한 장기적이고 연속적인 관리에 대한 중요성을 인식하며, 우주과학 연구에 참여하는 다양한 인력들이 참조하여 국내에서 생산되고 있는 자료를 활용하여 국내 우주과학 자료의 위상을 높이는데 기여하기를 희망한다. 자료에 대한 조사 내용은 한국우주과학회 홈페이지에서 다운로드할 수 있다(http://ksss.or.kr/).

• 한국수학사학회지
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• 제28권3호
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• pp.119-132
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• 2015

This survey is the second part of the history of science of Song and Yuan dynasties and will covers the period from Jin to Yuan. Following the first part, we look at the calendrical astronomy, mathematics and medicine. In this survey we again follow Yabuuchi's work on the history of science of Song and Yuan period and Du Shiran's work on the history of science of China. We start from the sciences and mathematics of Jin which inherited those of Northern Song and see how they influenced the whole China including Yuan and Southern Song. As a conclusion the tendency to practical usages in the Southern Song as well as the suppression of Han people in Yuan prevented developments of theoretical sciences in Yuan and Ming later.

• 천문학회보
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• 제40권2호
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• pp.60.1-60.1
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• 2015

We present the current operation status of StarDB web services by showing its user access statistics. The StarDB web services started its operation in late November, allowing world-wide users to access results of new variability analysis for Northern Sky Variability Survey light curves. New analysis results of various time-series data have been added to the StarDB services. Importantly, our services have supported a simple cone search, which is an internationally well-defined catalog search interface in the international Virtual Observatory systems. We have collected user access statistics such as how users find our analysis data since its operation in later November. We expect our analysis of the StarDB operation to help Korean community members who plan and operate their own web services preparing for a future era of big survey data.

• 천문학회보
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• 제38권2호
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• pp.55.2-55.2
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• 2013

We examine the effect of environment on star formation activity of a sample of a galaxy group catalogue constructed from the Sloan Digital Sky Survey(SDSS DR8) given in Tempel et al.(2012). As an environmental parameter, we use the richness of the galaxy group. According to this parameter, we select 6846 galaxies in dense environment and 297335 galaxies in low environment. By comparing the two samples, we identify the different relationship between star formation rate and stellar mass. In order to compare galaxies in different environment, we fixed other parameters(color, apparent magnitude), which can affect star formation efficiency except for stellar mass. Also, based on HI mass from the ALFALFA survey, we study the environmental dependence of Kennicutt-Schmidt law which show the correlation between star formation rate and gas content.

• 천문학회지
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• 제29권spc1호
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• pp.193-194
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• 1996

A large scale $^{13}CO$(J=1-0) survey was made for CMa OB1/R1 region in $220^{\circ}{\le}{\iota}{\le}230^{\circ}$ and $-10^{\circ}{\le}b{\le}10^{\circ}$ with a 8' spacing by using the 4 m radio telescope of Nagoya University. 34 isolated clouds were identified in this survey. Among them, two clouds were firstly identified by us. The observed LSR velocity indicate that almost of the all clouds are located in the Local arm, except two extreme velocity. The mass spectrum of the clouds in the Local arm is best fitted by a power-law index of 1.6.

• 천문학회보
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• 제35권1호
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• pp.66.2-66.2
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• 2010

We have studied the properties of interstellar turbulence as observed by Boston University-Five College Radio Astronomy Observatory (BU-FCRAO) Galactic Ring Survey (GRS). This observation uses 13CO J=$1{\rightarrow}0$ emission with high spectral resolution of 0.21 kms-1 and covers wide galactic plane regions ($18^{\circ}$ < 1 < $55.7^{\circ}$ and -1 < b < $1^{\circ}$). Firstly, we measured the one dimensional power spectrum of 13CO intensity along the galactic longitude and along the galactic latitude. We found the slope of the power spectrum changes around the molecular ring structure and the center of the galactic plane. Secondly, we explored how the power spectral slope is related with the velocity dispersion of supersonic giant molecular clouds in the GRS. Finally, we suggest the turbulent nature of the interstellar medium is connected with star formation activities in spiral arms.

• 천문학회보
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• 제43권1호
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• pp.59.2-59.2
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• 2018

Recent studies of galaxy clusters have shown that the galaxy clusters in dense environment tend to have lower star formation rate in local universe with z < 1. However, this correlation is not significant in galaxy clusters with z > 1. The study of galaxy clusters around z=1 can yield insight into cosmological galaxy evolution. Nevertheless, the identification of galaxy clusters beyond the scope of immediate local universe requires wide field data in optical and near-infrared bands. By incorporating data from Canada-France-Hawaii Telescope Legacy Survey(CFHTLS) and Infrared Medium-Deep Survey(IMS), the photometric redshifts of galaxies in CFHTLS W2 field were calculated. Using spatial distribution and photometric redshifts, the galaxies in the field were divided into redshift bins. The image of each redshift bin was analyzed by measuring the number density within proper distance of 1Mpc. By comparing high density regions in consecutive redshift bins, we identified the cluster candidates and mapped the large-scale structure within the CFHTLS W2 field.