• 천문학회지
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• 제29권1호
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• pp.75-81
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• 1996

We mapped the $^{13}CO$ line in the dark nebula L134 using the 14-m Taeduck radio telescope with a 57 arcsec beam and one beam spacing. The cloud has a spherical shape with an intensity peak ridge extended from the northwest to the southeast directions. The halfwidth and the radial velocity of the lines peak at the region of the cloud center. The radial velocity decreases from the cloud center towards the north and south directions. The integrated line intensity distributions in the space-velocity plane show some structure and a velocity gradient. The $^{13}CO$ and $H_2CO$ clouds and dark clouds are closely related in space in shape, outer boundary, and intensity peak positions. The $^{13}CO$ integrated line intensity is linearly proportional to the visual extinction.

• 천문학회보
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• 제46권2호
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• pp.62.3-63
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• 2021

남한과 북한의 천문 R&D 이슈와 협력 방안에 대해 연구하였다. 지난 2015년 과기부 남북과학기술 및 학술협력사업 '남북한 천문분야 활성화 및 협력방안 연구'를 계기로 북한의 천문연구 현황, 천문관측장비, 인력, 발행물, 책자 등의 자료를 수집하고 정리하였다. 이 자료들은 통일부 북한자료센터와 한국과학기술정보연구원 NK Tech에서 소장한 데이터들, 북한출판사 발행 간행물, 중국국가천문대, 네덜란드 레이덴 대학에서 보유한 북한 천문 관련 자료, 조선중앙통신과 노동신문과 같은 북한 언론매체 기사, 미국, 캐나다, 독일의 언론에 소개된 기사, 그리고 인터넷을 통해 수집한 자료들이다. 이 자료들을 통해 북한의 천문연구 현황을 이해하고 R&D 이슈는 무엇인지 살펴보려 한다. 또한, 정부와 과학계에서 진행되고 있는 남북한 연구 협력 노력에 대해서도 논의하려 한다. 이를 통해 북한의 천문연구 현황을 이해하고 남북천문협력 방안에 대해서도 제안하려 한다.

• 천문학회보
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• 제46권2호
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• pp.63.2-63.2
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• 2021

북한의 천문학 연구현황을 살펴보기 위해 북한 학자들의 연구 논문을 조사하였다. 북한 평양천문대에서 발행하는 대표적 천문학 학술지인 천문학통보를 비롯해 과학원 통보, 기상과수문 그리고 김일성종합대학학보인 물리학, 자연과학 등의 학술지에 게재된 천문학 논문을 조사하였다. 지난 10년간 북한 학술지에 실린 논문 중 확인된 150여 편 중에서 2015-2018년 천문학통보에 게재된 47편의 논문을 분석하였다. 그 결과 태양 분야 연구가 가장 활발하게 진행되고 있으며 고천문, 인공위성, 항성 등의 연구도 꾸준히 이어지고 있음을 알 수 있다. 북한 학자들의 해외 저널 논문을 조사한 결과 2007-2020년까지 16편을 확인하였다. 평양천문대, 김일성종합대학, 국가과학원 소속의 학자들이 주로 독일이나 중국의 학자들과 공동 논문을 발표하고 있는 것으로 확인된다.

• 천문학회지
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• 제29권spc1호
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• pp.357-358
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• 1996

Reanalysis of the observations of Mars made at the Hida Observatory in 1975 with a new image processing method is reported. Red filter images taken in the period before vernal equinox (areocentric longitude of the sun Ls=$0^{\circ}$) revealed dark surface features at the northern high latitudes, while blue filter images taken at the same time showed the extensive polar hood. The latitude of the northernmost feature observed was about $67^{\circ}$N. An extensive north polar cap, which is predicted by most of the existing models and observed with Viking, did not exist in our reanalyzed images obtained at the Hida Observatory in 1975.

• 천문학회보
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• 제44권2호
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• pp.74.3-74.3
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• 2019

SCUBA-2 North Ecliptic Pole survey, one of the ongoing JCMT large programs, is designed to obtain 850 ㎛ imaging data over ~4 deg² around the NEP based on the AKARI NEP-Wide survey. By August 2019, the program is 50 % complete in terms of observing time, increasing the submillimeter coverage by a factor of 2 with the comparable depth. The rms measured in the deepest center is 0.92 mJy/beam, slightly above the 850 ㎛ confusion limit. With 4 σ detection, the source count is 50 % complete at 9 mJy. The surface density of submillimeter galaxies at this flux limit is 200 deg^-2. Multi-wavelength identification of the 850 ㎛ sources was done through the likelihood analysis based on the far-infrared (250-500 ㎛), mid-infrared (18 ㎛), near-infrared (2-4 ㎛), and optical (i-band) source catalog. We are going to present morphologies and physical properties of 850 ㎛ selected submillimeter galaxies with the help of ancillary multi-wavelength datasets over the NEP area.

• 천문학논총
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• 제32권1호
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• pp.263-265
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• 2017

We present the mid-infrared (MIR) luminosity function (LF) of local (z < 0.3) star-forming (SF) galaxies in the North Ecliptic Pole (NEP) field. This work is based on the NEP-Wide point source catalogue and the spectroscopic redshift (z) data for ~ 1700 galaxies obtained by the optical follow-up survey with MMT/Hectospec and WIYN/Hydra. The AKARI's continuous $2-24{\mu}m$ coverage and the spectroscopic redshifts enable us to determine the spectral energy distribution (SED) in the mid-infrared and derive the luminosity functions of galaxies. Our $8{\mu}m$ LF finds good agreements with the results from SWIRE field over the wide luminosity range, while showing significant difference from the NOAO deep data in the faint end. The comparison with higher-z sample shows significant luminosity evolution from z > 0.3 to local universe. $12{\mu}m$ LF also shows a clear indication of luminosity evolution.

• 천문학회보
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• 제41권1호
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• pp.61.3-62
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• 2016

An asteroid family is a group of asteroidal objects in the proper orbital element space (a, e, and i), considered to have been produced by a disruption of a large parent body through a catastrophic collision. Family members usually have similar surface properties such as spectral taxonomy types, colors, and visible geometric albedo with a same dynamical age. Therefore an asteroid family could be called as a natural Solar System laboratory and is also regarded as a powerful tool to investigate space weathering and non-gravitational phenomena such as the Yarkovsky/YORP effects. We carry out time series photometric observations for a number of asteroid families to obtain their physical properties, including sizes, shapes, rotational periods, spin axes, colors, and H-G parameters based on nearly round-the-clock observations, using several 0.5-2 meter class telescopes in the Northern hemisphere, including BOAO 1.8 m, LOAO 1.0 m, SOAO 0.6 m facilities in KASI, McDonald Observatory 2.1 m instrument, NARIT 2.4 m and TUG 1.0 m telescopes. This study is expected to find, for the first time, some important clues on the collisional history in our Solar System and the mechanisms where the family members are being transported from the resonance regions in the Main-belt to the near Earth space.

• 천문학논총
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• 제30권2호
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• pp.741-743
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• 2015

We have designed and built three cost effective observatories, in distinct models, which can house Schmidt-Cassegrain type small telescopes having aperture sizes up to 16 inches. Using the available small telescopes, we provided the people of Manipura State in the far north-east corner of India the opportunity to observe directly with their own eyes the rare, spectacular events of the solar eclipse of January 15, 2010, lunar eclipse of December 10, 2011 and the transit of Venus of June 6, 2012. Apart from sharing a platform with the public for astronomy education and popularization through public outreach programs such as workshops, seminars and night watch programs, we have also developed a laboratory infrastructure and gained expertise in observational techniques based on photoelectric photometry, CCD imaging, CCD photometry and spectroscopy. Our team has become a partner in the ongoing international 'Orion project' headquartered in Phoenix, Arizona, USA which will be producing high quality photometric and spectroscopic data for five stars in the Orion constellation, namely Betelgeuse (alpha Orionis), Rigel (beta Orionis), Mintaka (delta Orionis), Alnilam (epsilon Orionis) and Alnitak (zeta Orionis). In the present paper, the authors would like to give a detailed report of their activities for the growth of astronomy in the state of Manipur, India.

• 천문학회보
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• 제43권2호
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• pp.33.3-34
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• 2018

Galaxy clusters contain a diffuse component of stars outside galaxies, that is observed as intracluster light (ICL). Since the ICL abundance increases during various dynamical exchanges of galaxies, the amount of ICL can act as a measurement tool for the dynamical stage of galaxy clusters. There are two prominent ICL formation scenarios; one is related to the brightest cluster galaxy (BCG) major mergers, and the other to the tidal stripping of galaxies. However, it is still under debate as to which is the main ICL formation mechanism. In this study we improve on earlier observational constraints of the ICL origin, by investigating it in a massive fossil cluster at z~0.47. Fossil clusters are believed to be dynamically matured galaxy clusters which have dominant BCGs. Recent simulation studies imply that, BCGs have assembled 85~90% of their mass by z~0.4 (e.g., Contini et al. 2014). Thus our target is an optimal test bed to examine the BCG-related scenario. Our deep images and Multi-Object Spectroscopic observations of the target fossil cluster (Gemini North 2018A) allow us to extract the ICL distribution, ICL color map and ICL fraction to cluster light. We will present a possible constraint of the ICL origin and discuss its connection to the BCG and the host galaxy cluster.

• 천문학논총
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• 제32권1호
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• pp.201-203
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• 2017

There exists strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies; however it is still under debate how such a relation comes about and whether it is relevant for all or only a subset of galaxies. An important mechanism connecting AGN to their host galaxies is AGN feedback, potentially heating up or even expelling gas from galaxies. AGN feedback may hence be responsible for the eventual quenching of star formation and halting of galaxy growth. A rich multi-wavelength dataset ranging from the X-ray regime (Chandra), to far-IR (Herschel), and radio (WSRT) is available for the North Ecliptic Pole field, most notably surveyed by the AKARI infrared space telescope, covering a total area on the sky of 5.4 sq. degrees. We investigate the star formation properties and possible signatures of radio feedback mechanisms in the host galaxies of 237 radio sources below redshift z = 2 and at a radio 1.4 GHz flux density limit of 0.1 mJy. Using broadband SED modelling, the nuclear and host galaxy components of these sources are studied simultaneously as a function of their radio luminosity. Here we present results concerning the AGN content of the radio sources in this field, while also offering evidence showcasing a link between AGN activity and host galaxy star formation. In particular, we show results supporting a maintenance type of feedback from powerful radio-jets.