Many astrophysical fluids are strongly magnetized and in turbulent state. Since magnetic fields affect many physical processes, measuring their strengths is of great importance. First, I will talk about a technique called Davis-Chandrasekhar-Fermi (DCF) method, which is the most popular method for obtaining magnetic field strengths in molecular clouds. The DCF method is based on polarized emission from dust grains. Interstellar dust grains tend to be aligned with magnetic field and thermal emission from aligned grains is polarized in the direction perpendicular to magnetic field. Therefore, if we observe polarization of thermal radiation from dust grains, we can derive information about magnetic field. Second, I will discuss the limitations of the DCF method. Third, I will talk about a modified DCF method. Fourth, I'll talk about a technique that can remove a large-scale (e.g., hourglass-shaped) magnetic field component, which make it difficult to correctly measure the strength of magnetic field in the cloud.

근세에서 근대에 이르는 시기(15~19세기) 동안, 서양은 거의 모든 면에서 동양을 앞질렀다. 이것은 15세기 포르투갈에 의해 시작된 대항해 탐사, 대륙간 무역에서 얻어질 부(富)에 대한 욕망, 미지의 세계에 대한 호기심과 과학적 접근, 신대륙 탐사 비용 마련을 위해 시작된 자본주의 등으로 인한 결과이다. 동서양을 통틀어 현재 우리를 지배하고 있는 경제, 사회, 국가 체계의 대부분이 바로 이 "발견의 시대"에 형성된 것이라 봐도 무방하다. 21세기에 들어서면서 민간 주도의 우주탐사가 본격화 되고 있으며, 이는 근세에 일어났던 민간자본 주도의 신대륙 탐험과 여러 면에서 유사하다. 본 발표에서는 근세 서구 열강들의 신대륙 (New World) 탐사/착취 과정을 되돌아 보고, 이를 21세기의 민간주도 우주탐사 (“New Space”)와 비교해 본다.  

Vast quantities of dust observed in high red-shifted galaxies raise the fundamental astrophysical question of the origin of dust in the early Universe because the timescale of the primary source of dust formation, AGB stars to release their dust is too long. Herschel and Spitzer observations of two young supernova remnants (SNRs) G54.1+0.3 and Cas A provides the total dust-mass estimates, which range 0.1-1 Msun and suggests that supernovae are a significant source of dust in the early Universe. We present Herschel FIR catalog of known SNRs in the Galactic plane and the implication of their far-IR emission. Out of 190 SNR samples, we detect dust signatures in 39 SNRs, including 13 core-collapse SNRs. To understand the gaps of dust mass between supernovae (SNe) and young SNRs, we have started a Gemini observing campaign to observe newly exploded supernovae in nearby galaxies. We present the first example of eleven near-infrared (0.8 − 2.5 microns) Gemini spectra of the Type II-P SN 2017eaw and a set of optical and IRTF spectra of SN 2018hna. The spectra show the onset of CO formation and newly-formed hot dust, in addition to numerous lines of hydrogen and metals, which reveal the change in ionization as the density of much of the ejecta decreases. We will present a plan of Gemini ToO SNe observations during 2020A and a perspective to study dust formation in SN ejecta using GMT. We will also show  SOFIA far-IR [O I] and [O III] maps and possibly polarization map of Cas A. Lastly, I will show ground-based CO millimeter observations and molecular hydrogen detection from SNRs, which are interacting with molecular clouds, which are ideal for follow-up JCMT and ALMA observations. 

Abstract: This talk aims to help researchers in astronomy, space science and engineering understand space economy and the future direction of space exploration from an economical aspect. We will overview the current and future space economy including satellite services, space tourism, and space mining. Then we will examine the NASA commercial space program in the Low Earth Orbit (LEO), the Moon and the Deep Space. To understand the LEO space economy, we will look into NASA’s Commercial Orbital Transportation Services (COTS), Orbital ATK and SpaceX commercial resupply services contracts, and commercial activities at the International Space Station. To understand the space economy in the Moon and the Deep Space, we will exam the NASA Commercial Lunar Payload Services (CLPS), and the commercial partnerships for the Moon and Mars Technologies.

There are presently some 25 highly r-process-element-enhanced metal-poor (r-II) stars known in the Galactic halo, roughly twenty-five years after their first recognition. These stars exhibit enhancements of their r-process-element to iron ratios, relative to Solar ratios, by a factor of 10 to 100+ ([r-element/Fe] > +1.0). Despite their very low metallicities ([Fe/H < –2.0), these stars exhibit an apparently universal [r-element/Fe] pattern that is very well-matched to the Solar     r-process pattern. As such, they have long been thought to provide fundamental information on the likely astrophysical site of the r-process.  We describe a comparison of the observed properties of halo r-II stars with the remarkable recent detection of a large sample of r-II stars identified in the Ultra Faint Dwarf (UFD) galaxy Reticulum-II, and suggest that the UFD environment is the natural birthplace of essentially all r-II stars. This hypothesis has received support from the identification of lanthanide signatures in photometric and spectroscopic observations of the kilonova associated with the LIGO/Virgo neutron star merger discovery.  A new large-scale effort to dramatically increase the numbers of recognized r-II stars (from ~25-~100-150) is now underway; current results will be reported on, including the identification of numerous new bright r-II stars, several of which have detectable U and Th. 

Stars and planet-forming disks form out of cold and dense clouds. One of the major questions is whether or not the disk inherits the material of the protostellar envelope. Models of the young solar nebula, the disk that formed the Solar System, suggest that the chemical composition has been reset on the way to the disk as the meteoritic studies showed.  However, it has been only recently that it is possible to study the early stages of star formation with the detail required to compare with the young solar nebula models. I will present the on-going projects to understand the disk formation process and its implications on the early stages of planet formation and the origin of the Solar System.

황도광이란 황도면에 주로 분포하는 미세한 고체입자들에 의해 산란된 태양빛으로 야천광의 중요한 성분 중 하나이다. 황도광은 주로 해가 진 후 서쪽 지평선 부근에, 또는 해 뜨기 전 동쪽 지평선 부근에서 황도를 중심으로 삼각형 형태로 희미하게 빛나며 태양에서 멀어질수록 급격히 어두워진다. 황도광의 밝기 분포를 이용하여 행성간 입자의 공간 분포 특성을 이해할 수 있으며 이들의 기원에 관하여 연구할 수 있다. 한편 적외선 망원경을 이용하여 황도 방출광의 관측이 이루어지고 이를 분석하여 행성간 입자의 온도와 적외선 방출도 등 티끌의 물리적 성질에 대한 연구가 이루어지고 있다.   황도광에 관한 연구가 본격적으로 이루어지기 시작한 것은 1960년대 하와이 할레아칼라 관측소에서 다양한 파장대에 대하여 이루어진 편광/측광 전천 스캔 관측 자료의 분석으로부터 시작되었다고 할 수 있다. (Weinberg and Mann, 1968) 이 하와이 야천광 관측 자료의 일부를 분석하여 황도광 밝기 분포의 소규모 구조에 대한 연구 결과를 발표한 것이 우리나라에서 최초의 황도광을 비롯하여 행성간 입자와 관련된 연구라 할 수 있으며(Hong et al. 1985), 그 이후 황도 방출광, 행성간 입자 및 야천광 및 대기광 등 다양한 관련 분야에 대한 연구가 이루어지고 있다. 이 발표에서는 그동안 우리나라에서 이루어진 황도광 및 황도 방출광과 관련된 연구에 대하여 간략히 살펴보고자 한다. 특히 우리나라의 황도광 연구를 개척한 고 홍승수 교수님의 연구 업적을 중심으로 이루어진 연구 성과를 요약하자 한다.

The Las Campanas Observatory (LCO) owned by the Carnegie Institution for Science has been established in Chile in 1969. Two telescopes were commissioned in the 1970s. The Swope 1-meter which began observations in 1971 and  the duPont 2.5-meter that started in 1977. Both telescopes are still routinely used  by Carnegie astronomers  and international collaborations. At the beginning of the 2000s the Carnegie Institution, University of Arizona, Harvard University, University of Michigan and Massachusetts Institute of Technology put in operation the twin 6.5 meter Magellan telescopes. With their excellent optical performances and the superb seeing conditions the Magellan telescopes are being recognized among the best ground based astronomical observing facilities. The success of the project inspired the construction of the 25 meter Giant Magellan Telescope, which is expected to see first light in the next decade. In my  talk I will report  on  the LCO telescopes current and future capabilities  and briefly present some of the research activity  at the observatory. 

Nicky Fox:   Journey to the Sun   Abstract: NASA heliophysics research studies a vast system stretching from the Sun to Earth to far beyond the edge of the planets.  Studying this system – much of it driven by the Sun’s constant outpouring of solar wind -- not only helps us understand fundamental information about how the universe works, but also helps protect our technology and astronauts in space. NASA seeks knowledge of near-Earth space, because -- when extreme -- space weather can interfere with our communications, satellites and power grids. The study of the Sun and space can also teach us more about how stars contribute to the habitability of planets throughout the universe.   Mapping out this interconnected system requires a holistic study of the Sun’s influence on space, Earth and other planets.  NASA has a fleet of spacecraft strategically placed throughout our heliosphere -- from Parker Solar Probe at the Sun observing the very start of the solar wind, to satellites around Earth, to the farthest human-made object, Voyager, which is sending back observations on interstellar space. Each mission is positioned at a critical, well-thought out vantage point to observe and understand the flow of energy and particles throughout the solar system -- all helping us untangle the effects of the star we live with.    Arik Posner:   A Case for a Mission to Earth-Sun L4   The goal of Heliophysics science is to improve understanding of the Heliophysics system. Scientific understanding of coupled processes at the Sun, the Heliosphere and the Magnetosphere/Ionosphere system is best demonstrated by successfully forecasting of the behavior of the entire system. Besides that, a forecasting capability may have important real-world applications. Placing a sentinel spacecraft at Earth-Sun (E/S) L1, ~1.5M km upstream of Earth, has demonstrated utility for forecasting magnetospheric space weather through in-situ measurements of solar wind structures up to one hour before they reach Earth.  The usefulness of E/S L5, 60 degrees behind Earth in its orbit, has recently been argued as important in this context as well, specifically through providing a “side-view” of the Earth-Sun line that can be monitored by heliospheric imagers, potentially extending lead-time, and by “peeking” around the east limb of the Sun in order to have advance knowledge of any active regions before they reach the visible disk as viewed from Earth. A vantage point that not been paid sufficient attention to in the scientific literature is the E/S L4 location, 60 degrees ahead of Earth in its orbit. The considerable advantages of this location for Heliophysics science and associated space weather applications, including a rationale for a subset of the needed scientific payload elements, will be discussed.

- 아카이브란 무엇인가? - 한국천문연구원 기록의 종류 - 아카이브 사례 - 천문아카이브 만들어 보기

- 코스모스 오디세이 영화 내용 간단 소개 - 영화 제작 과정  - 첨단 천문학의 현장 방문기 - 미국 vs 유럽 vs 대한민국 - 어쩌다 천체사진가가 영화까지 만들게 되었나 - 해외 천문 기관의 천체투영관 영상물 활용 사례

Numerous international astronomy reports have recently highlighted the need for fully dedicated, large aperture, massively multiplexed spectroscopy in the optical and near-Infrared wavelength regimes. Such a facility is the most obvious missing link in the emerging network of ground-based observational facilities world-wide. The Maunakea Spectroscopic Explorer (MSE) is a planned 11-m telescope facility designed to fill this scientific gap. MSE is an evolution of the Canada-France-Hawaii Telescope and is completely dedicated to multi-object optical and near-Infrared spectroscopic surveys of millions of astrophysical objects at a range of spectral resolutions. In this talk I will review the current design status of the project and provide an overview of MSE's wide range of scientific capabilities.

2002-2005년에 백두산에서 8,000여회의 화산지진이 발생하고 천지가 수cm 부풀어 오르는 화산징후가 있었다. 이 이벤트는 백두산이 활화산임을 일깨워 주었고, 화산분화에 대한 심각성을 인식시켰다. 북측은 2007년, 2011년, 2015년, 3차례에 걸쳐 남측에 백두산 남북공동연구를 제안하였고, 양측 전문가 대표들이 접촉까지 하였으나, 불안정한 남북관계로 인해, 아직 실제 연구단계에 들어가지 못한 실정이다. 3차에서 양측 대표는 백두산 마그마 과학시추연구 추진에 동의하였고, 연구의 지속성과 효율성을 높이기 위해, 국제연구그룹을 결성하는데 합의하였다. 한편 천지아래에 위치한 마그마 가까이 시추공을 뚫고, 화산미그마의 물리적-화학적 움직임 변화를 직접 관측하는 방법은 금세기 화산분화예측연구의 추세로써, 지구촌 첨단과학기술이 집결되어야 가능하다. 현재까지, 전 세계로부터 저명한 전문가들이 백두산 연구그룹에 합류하였으며, 국제적으로 명성이 높은 학술기관인 미국과학진흥협회(AAAS, SCIENCE 지 발간)와 국제대륙과학시추프로그램(ICDP)도 함께 동참하게 된다. 그만큼 이 연구의 백두산 분화예측 성공확률이 높다는 것을 시사한다. 특히 AAAS는 민간차원에서 남한과 북한을 연결해 주는 역할을 자청하여 주었고, ICDP를 통해 지구촌의 주요 화산 마그마 프로젝트들과 과학기술연계가 이루어질 예정이다.   백두산 화산분화 예측 연구는 유사시 소중한 생명을 보호하고, 재산피해를 줄일 수 있다. 이는 우리민족의 안보와 미래를 확보할 수 있고, 중국의 동북공정(장백산 명칭 고착화, 장백산세계자연유산)에 적극 대응하는 일이다. 중국학자들은 이들 결과를 국제학계에 장백산의 이름으로 활발히 보고하고 있어 자연스럽게 백두산 이름을 대체하고 있는 실정이기 때문이다. ‘동해물과 백두산이...’로 시작되는 우리나라의 애국가의 위기이다. 백두산 마그마 과학시추프로젝트는 국내 및 해외 화산전문가들이 제안하여 세계적인 백두산전문가그룹과 국제기구(ICDP, AAAS)가 협력체제를 구축하여 추진되고 있으며, 현재 중국지진국 백두산연구그룹에 절대 우위를 확보하고 있다. 무산 시 우리는 힘들게 이뤄진 절호의 기회를 놓치게 되는 것이다. 이 연구는 남과 북, 그리고 지구촌의 과학기술협력을 통해 남과 북이 신뢰를 회복하고, 북한 과학계를 국제과학교류의 장으로 이끌어내어, 소중한 생명을 구하고 자연 보호의 공통선을 추진함으로써 남북평화에 기여할 것이다.   이 연구는 3단계로, 제1단계(초기 3년)는 화산지질조사, 마그마 지구물리화학탐사, 과학시추/초소형 관측장비 설계 및 안전계획수립, 마그마 모니터링-모델링 설계로 나뉘어 추진한다. 제2단계는 제1단계의 설계에 따라 마그마 가까이 과학시추를 가행하여 심도 별로 초소형 관측장비들을 설치하고, 마그마 모니터링-모델링 설계를 테스트하며, 모니터링 자료들을 실시간으로 받을 수 있는 백두산과학기지를 세우게 된다. 제3단계는 백두산 화산 마그마에서 나오는 다양한 물리화학신호들을 실시간으로 받아 백두산 화산마그마 분화 모델에 적용하고 실제와 가깝게 되도록 모델을 수정해 나간다. 또한 이 자료들을 모아 빅데이터를 구축하여 캄퓨터 AI(인공지능) 결과와 경쟁을 거치고 개선해 나감으로써 분화예측 수준을 높이게 될 것이다. 이 연구가 순조로이 진행된다면 필시 백두산이 10년 이내에 세계에서 모범적인 화산예측-관측기지로 떠오를 것으로 확신하며, 관련된 다양한 분야 및 융합분야에서 우수한 젊은 과학기술자를 계속하여 길러냄으로써 우리나라가 미래극한과학기술분야를 선도할 수 있는 기회를 갖게 될 것이다.

Abstract:  As most of the molecular clouds are filamentary and elongated, the magnetic fields (B-fields) in these clouds are found either parallel or perpendicular to the main axes. In the talk, I will present the B-fields mapped in IRDC G34.43+0.24 using 850 micron polarized dust emission observed with the POL-2 instrument at JCMT. We examine the magnetic field geometries and strengths in the northern, central, and southern regions of the filament. The overall field geometry is ordered and aligned closely perpendicular to the filament's main axis, particularly in regions containing the central clumps MM1 and MM2, whereas MM3 in the north has field orientations aligned with its major axis. The overall field orientations are uniform at large (POL-2 at 14” and SHARP at 10”) to small scales (TADPOL at 2.5” and SMA at 1.5”) in the MM1 and MM2 regions. The SHARP/CSO observations in MM3 at 350 micron from Tang et al. show a similar trend as seen in our POL-2 observations. TADPOL observations demonstrate a well-defined field geometry in MM1/MM2 consistent with MHD simulations of accreting filaments. We obtained a plane-of-sky magnetic field strength of 470+/-190 micG, 100+/-40 micG, and 60+/-34 micG in the central, northern and southern regions of G34, respectively, using the updated Davis-Chandrasekhar-Fermi relation. The estimated value of field strength, combined with column density and velocity dispersion values available in the literature, suggests G34 to be marginally critical with criticality parameter values 0.8+/-0.4, 1.1+/-0.8, and 0.9+/-0.5 in the central, northern, and southern regions, respectively. The turbulent motions in G34 are sub-Alfvénic with Alfvénic Mach numbers of 0.34+/-0.13, 0.53+/-0.30, and 0.49+/-0.26 in the three regions. The observed aligned B-fields in G34.43+0.24 are consistent with theoretical models suggesting that B-fields play an important role in guiding the contraction of the cloud driven by gravity. I will also discuss some of my ongoing projects where I am investigating the dust grain characteristics such as heating, radiative alignment, and collisional disalignment of grains. 

The Fermi Gamma-ray Space Telescope with its main instrument onboard, the Large Area Telescope, opened a new era in the study of high-energy emission from Active Galactic Nuclei. When combined with contemporaneous ground- and space-based observations, Fermi-LAT achieves its full capability to characterize the jet structure and the emission mechanisms at work in different classes of radio-loud AGN, i.e. blazars, radio galaxies and narrow-line Seyfert 1 galaxies. In this talk I will discuss the broad-band properties of gamma-ray-emitting AGN, highlighting major findings and open questions regarding the jet physics, cosmological evolution, and accretion processes of super-massive black holes in the Fermi era. Furthermore, I will discuss the perspectives for future studies of relativistic jets in AGN with the Large Synoptic Survey Telescope from near-infrared to ultraviolet and the Cherenkov Telescope Array at Very High Energy.

  조선 중기는 외침이 많고 기아와 전염병으로 많은 사람이 죽어간 살기 어려운 시대였다. 이런 부정적 역사 이미지는 과거 공리공담을 일삼은 성리학이 저지른 인재(人災)의 결과로 보았다. 나는 같은 시기 서양에서도 고난과 혼란의 역사가 있었고 일각에서 그 원인을 자연 이상 현상에서 찾는 연구자들이 있는 것을 알게 되어, 의 자연 이상 현상에 관한 기록 25,000여 건을 발췌 분석하여 1490년부터 1760년까지 무려 260년간 ‘소빙기’ 자연이상 현상이 계속된 것을 확인하였다. 나의 답은 역경의 원인이 인재가 아니라 천재(天災)라는 것이었다.   기온 강하와 관련한 기록과 동시에 잦은 유성 출현에 관한 수많은 기록에 접하여 당황하였지만, 천체 물리학 전공의 소광섭 교수의 안내로 외계충격(Terrestrial Impact) 학설에 접하여 이의 활용을 통해 수많은 연관 현상을 체계적으로 파악할 수 있었다. 이 작업을 진행하던 중에 의 자연 이상 현상과 거의 같은 내용을 담은 독일의 그림 자료(flugblatt)가 있는 것을 알게 되어 약 90여 점을 입수하여 기록의 묘사와 대조하여, 이 시기의 이른바 소빙기(little ice age) 현상이 전 지구적 경험이란 것을 입증할 수 있게 되었다.   태양계 속의 지구는 태양계의 메카니즘으로부터 자유로울 수 없다. 지구 위의 모든 생명체는 태양계의 우주 현상인 ‘외계충격’의 메카니즘의 영향을 받을 수밖에 없다. 생존에 필요한 하드웨어뿐만 아니라 신앙, 종교 등 감각, 정신의 소프트웨어에도 많은 영향을 받아 왔다. 태양계의 메카니즘을 밝히는 우주 과학의 성과로 인류역사에 대한 해석도 새로워 질 수 있게 되었다. 의 충실한 자연이상 기록이 21세기 세계 역사학을 새롭게 바꾸어 놓을 전망이다.

TITLE1: European Solar Telescope: Recent progress ABSTRACT1: The main goal of EST is the simultaneous observation of the solar photosphere and chromosphere to understand the complex interaction between the plasma and the magnetic field. The drastic changes in the plasma beta parameter between these two layers affect drastically the way this interaction takes place and has profound implications on the required spatial and temporal scales of the observations, as well as on the polarimetric sensitivity that is needed to adequately detect the polarization signals. In this talk, we will summarize the most stringent requirements and how the suite of instruments of EST have been defined. A number of recent instrumental and numerical developments carried out by members of the project have paved the way for the practical implementation of novel instruments that will make possible for EST to be at the frontier of technological development since first light. These have especial relevance in the field of adaptive optics, integral field units and applications of neural networks. In this talk, all these concepts will be revised, together with the timeline of the project. ================================================================================ TITLE2: Impact of partial ionization on the solar atmosphere ABSTRACT2: The partial ionization of the solar atmosphere has been receiving increasing attention in recent years. The presence of neutrals can, for instance, modify the equilibrium of magnetic structures, introduce instabilities under certain magnetic configurations, lead to plasma heating, or change the way the various wave modes transform into each other and propagate through the atmosphere. These are aspects that, in some cases, have been studied in simple scenarios to find analytical expressions that determine the plasma and the field behavior. More recently, advanced numerical simulations have allowed to gain insight into them with more complex magnetic and plasma configurations. Under an observational point of view, there is little evidence of these phenomena or of the potential decoupling between the neutral and ionized species in some circumstances. With the advent of new large aperture telescopes, some of these effects may be observable. In this talk, I will comment some observational and numerical results obtained by the IAC group related to the impact of partial ionization on solar phenomena.

The next decade will see the arrival of three 30m-class Extremely Large Telescopes (ELTs). These giants are promising profound transformation of our understanding of the universe through large-scale surveys of a myriad of previously unseen astronomical objects across vast areas of sky and cosmic space-time. To carry out such surveys, the ELTs must have i) a super-efficient wide-field corrector (WFC) that can expand their field of view (FOV) over a broad wavelength range and ii) highly multiplexed multi-object spectrographs to target a number of objects simultaneously. The McDonald Observatory (MDO) has a strong heritage not only in designing and building traditional astronomical instruments, but also in developing novel instruments and technologies that are directly scalable to the ELT-class wide field survey sciences. I will highlight some of the scientific opportunities brought forth by the ELT Wide-Field MOS (WfMOS) capability and the MDO’s instrument programs that can enable such capability in the era of ELTs and beyond.

The evaluation of the global atmospheric structure, variation, and loss rate is key to a better understanding of the physics that drives the current state of the Martian atmosphere. Operating for more than 2 Mars years, the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission has provided an unprecedented opportunity to study the spatial and temporal variability of the Martian upper atmosphere and ionosphere and their interaction with the solar wind under both nominal and disturbed conditions. One of the primary goals of the MAVEN mission is to characterize the atmospheric loss rates at Mars and understand the relations between those escape rates and solar drivers. Among the dominant atmospheric loss processes, photochemical escape is the major loss process of heavy atomic species, where the escape rate is not directly measured by MAVEN, requiring numerical models to constrain. This talk will present comprehensive modeling efforts of photochemical escape process and formation of the hot atomic coronae at Mars for various atmospheric conditions. The talk will also present the observed and modeled characteristics of the Martian upper atmosphere and ionosphere, that are relevant to the photochemical escape process.

The studies of planet formation have been heavily dominated by theoretical work because observing planets in formation was not possible. The situation is however gradually changing. Thanks to increasingly powerful observing facilities and techniques, we are now able to peer into the birthplaces of planets – so-called circumstellar disks – and routinely find signatures hinting at, and for a few systems direct evidence of, on-going planet formation. In this talk I will introduce how planet formation theories are being tested with and improved by observational data. In particular, I will present a specific example PDS 70, a 5-million-year-old young star surrounded by a disk of gas and dust with two accreting giant protoplanets detected across a broad range of wavelengths from optical to millimeter, offering a perfect test bed for planet-disk interaction and planet formation theories.

천문학은 우리 역사에 깊이 관여돼 있다. 그 중요성은 라대일 박사와 박창범 박사가 『단군세기』에서 ‘戊辰五十年五星聚婁’ 기록을 발굴하고 이를 천문학적으로 증명하면서 크게 부각됐다. 이것은 ‘BC 1733년 오성이 루 주위에 모였다’ 같이 해석되는 단군조선시대의 천문기록이다. 이런 사실이 우리 역사에 미치는 영향에 대해 알아보기로 한다. 또한 지금까지 우주의 역사는 대부분 서양의 관점에서 기술됐다는 점도 짚고 넘어가기로 한다. 가장 좋은 예가 교육과정에서 서양의 아리스토텔레스 4원소는 가르치면서 동양의 태호복희 5원소는 가르치지 않는다는 것이다. 그 결과 대한민국 국민 대부분이 학창시절 태극기의 원리를 제대로 배우지 못했다. 최소한의 태극기에 대한 지식도 알아보기로 한다.

Planet formation is the process where dust grains grow to pebbles, planetesimals, and rocky planets or cores of gas giant planets in protoplanetary disks. The process as well as the planetary properties such as masses can be imprinted in disks, thus obtaining the detailed disk structure is central to understand how the planet forming activity proceeds in the entire regions of the disks. I will review the recent results of disk observations mainly with the Atacama Large Millimeter/submillimeter Array (ALMA). The fine disk structures/substructures have been resolved with about 5-au resolution of ALMA in dust continuum, and those images often show that the disks consist of concentric annuli, or sometimes show the spiral arms or strong non-axisymmetry. Combined also with the gas observations, plausible mechanisms to explain those structures include the trapping of dust particles at the local pressure maxima and the disk-planet dynamical interaction.

A unique QPO often occurs at 6 Hz in Z type Neutron star sources radiating close to the Eddington limit. From radio observations, it is known that a jet is present during the 6 Hz QPO and sometimes ultra relativistic flow is also associated. In general these sources the QPO varies from ~20-50 Hz during which the inner region of accretion disk is truncated and a Compton cloud/corona is present inside the truncation radius. As the truncated front approaches close to the last stable orbit (50 Hz), suddenly a unique 6 Hz QPO appears. I will discuss a model which probably explains the sudden emergence of the 6 Hz QPO along with 50 Hz QPO. In this model, I study the disk oscillation during which the inner region of the disk dominated by radiation pressure assuming that the oscillation is driven by the gravitational force. I will also use this model explain the sudden occurrence of type-B/A QPOs in black hole X-ray binaries which are similar to the 6 Hz QPO in neutron star source.

Most globular clusters in the Milky Way show signs of multiple stellar subpopulations. These may be due to distinct star formation events, as suggested by differing chemical abundance patterns. Photometric coordinates designed to be sensitive to light-element abundances -the so-called chromosome-map plane- were recently introduced to distinguish subpopulations without resorting to spectroscopy. However, drawing boundaries between subpopulations on the chromosome-map plane is somewhat subjective, as it ultimately depends on the judgment of a human expert. I will discuss unsupervised machine learning strategies to make this process automatic so that it can become reproducible and be generalised to a large set of GC observations. In particular I will show that the AGglomerative NESting (AGNES) algorithm with Ward's linkage produces results similar to expert expectations on NGC 2808.

양자광학에서 가장 기초적이고 중요한 실험중의 하나는 Hanbury-Brown—Twiss (HBT) 실험이다. Robert Hanbury-Brown은 2차 세계대전 중 레이더의 개발에 깊이 관여했었고 2차대전 후에는 Richard Twiss와 함께 전파망원경 분야에 전념하였다. Hanbury-Brown과 Twiss는 Intensity interferometer를 최초로 제안하였는데, 그 가능성을 보여주는 (HBT 실험이라고 불리는) photon bunching 실험을 1956년 발표하였다. HBT 실험은 그 자체로는 빛의 양자적 특성을 보여주지는 않지만, 현대 양자광학에서는 빛의 양자성을 구별하는데 필수적인 테스트로 사용된다. 이번 발표에서는 Hanbury-Brown과 Twiss의 전파망원경 연구가 실험실 양자광학의 태생으로 이어진 과정을 소개하고 현대 양자광학에서 중요한 몇 가지 개념과 실험들을 소개한다. 최근 실험실 양자광학은 장거리 양자통신의 중요성과 연결되면서 장거리 양자광학 실험으로 확장되고 있다. 지난 몇 년간 보고된 장거리 양자통신 실험 또한 간단히 소개한다.

온라인 게임, 특히 '대규모 다중 사용자 온라인 역할 수행 게임 (Massively Multi-Online Role Playing Game, MMORPG)'에서 사람들은 채집이나 수렵 등의 생산, 퀘스트 수행 및 레벨업을 통한 성장, 거래를 통한 경제 활동, 파티/혈맹/친구 관계와 같은 협업과 전투를 통한 경쟁 등의 다양한 사회 활동을 수행한다. 이렇게 사람들이 가상 세계에서 벌이는 다양한 활동 및 사회 관계 정보는 로그와 DB 형태로 기록된다. 따라서 게임 데이터는 기존의 사회 과학에서는 접하기 거의 불가능한 수준의 폭넓고 세밀한 정보를 갖고 있는, 세상에서 가장 흥미로운 데이터 중 하나이다. 한편, 최근 기계 학습 분야의 큰 발전으로 인해 다양한 분야에서 이를 실전에 적용하려는 시도가 이뤄지고 있다. 그러나 괄목할 만한 연구 성과에 비해 아직까지 실전에서의 성공 사례는 많지 않다. 여러 가지 원인이 있겠으나 기계 학습 모델링 측면에서 보자면 학습 데이터 확보의 어려움, 높은 특성 공학 비용, 데이터가 가진 통계적 특성의 변화에 의한 빠른 모델 노후화 등의 문제를 꼽을 수 있다. 온라인 게임 분야 역시 이 세 가지 문제가 기계 학습 모델을 실전에 적용하는데 큰 걸림돌이 되고 있다. 엔씨소프트는 2009년부터 하둡을 이용한 빅데이터 인프라를 구축하였으며, 2019년 현재 일일 발생량 11테라바이트, 축적 용량 6페타바이트에 달하는 대규모 데이터를 이용해 기본적인 현황 분석부터 고객 세그먼테이션, 이상 탐지, 어뷰징 탐지, 이탈 예측 등 다양한 분석에 활용하고 있다. 본 강연에서는 엔씨소프트에서 진행하는 분석 사례와 함께 기계 학습 모델을 실제 서비스에 적용하기 위해 극복해야 할 도전 과제에 대해 소개한다.

Active asteroids are objects that orbit in the main asteroid belt but show transient, comet-like dust emission. Newly discovered active asteroid P/2018 P3 (PANSTARRS) has a semimajor axis 3.006 AU, eccentricity 0.415, inclination 8.9 deg, placing it within the dynamical boundary region between asteroids and comets. This object has been recurrently active near two successive perihelia (at 1.75 AU), indicative of the sublimation of volatile ices. We obtained Hubble Space Telescope observations of P/2018 P3 from 2018 September to 2018 December, in order to study the morphology of the ejected dust at superb spatial resolutions. Numerical modeling of P/2018 P3's dust emission showed that the properties of the ejected dust are remarkably consistent with those found in other sublimating active asteroids (e.g., the continuous emission of >10 μm particles at 0.2-3 m/s speeds). Unlike low-eccentricity active asteroids which are assumed to be native to the main belt, our dynamical analysis suggests that P/2018 P3 appears unstable on timescales >10 Myr and is likely to be a recently implanted interloper. We also find that several synthetic Jupiter-family comets studied by Brasser & Morbidelli (2013) briefly take on P/2018 P3-like orbital elements during their evolution. As such, we speculate that P/2018 P3 is a captured Jupiter-family comet that has been residing in the main belt for >10 Myr, finally becoming indistinguishable from weakly sublimating active asteroids in terms of the dust properties.

In my talk, I will give a brief introduction to thermal and thermophysical models that are widely used for interpretation of the thermal infrared radiation of asteroids. These include the NEATM model developed by Harris (1998) and the thermophysical model of Lagerros (1996, 1997, 1998). I will discuss the effects of thermal inertia and surface roughness on the emitted radiation and show how these properties can be derived by the means of a thermophysical model. I will apply the thermophysical model to hundreds of asteroids with known shape model and available thermal infrared data from the WISE satellite. Finally, I will also discuss the thermophysical properties of near-Earth asteroid (3200) Phaethon, the target of the proposed DESTINY+ mission of JAXA.

This pioneering work ties the origin of probabilities we use (both in scientific analysis and everyday life) to quantum fluctuations. One important conclusion is that in many cases people have been using probabilities incorrectly when applied to multiverse theories. [References] Technical work A. Albrecht and D. Phillips Origin of probabilities and their application to the multiverse. arXiv:1212.0953 Slides from a more recent talk (June 2015) Video of a short talk at the Jan 2014 FQXi conference focusing on implications for cosmology ICTP Colloquium (June 2013): Video (This talk contains the substance of our ideas about probabilties, but to understand our current views on the implications for multiverse theories, please look to any of the above materials.) Accessible material in the media New Scientist Article (From issue 2898 of New Scientist magazine, page 8-9) Is Luck Real? Through the Wormhole with Morgan Freeman (Season 5, Episode 2, first aired March 2014) Rules for computing classical probabilities might depend on quantum randomness Science News Jan 23, 2013 Quantum Ignorance (UNconstant Blog 1/15/2013) Why Every Coin Flip May Be a Schrödinger’s Cat Facts so Romantic on Matter (June 12, 2013)

Optical quantum information processing can be classified into two categories depending on the way of encoding quantum information on light: one harnesses the particle nature (photon)−called discrete-variable approach−, and the other exploits the wave nature (electric field)−called continuous-variable approach. Basic nonclassical lights for the two are single photon and squeezed vacuum, respectively. Recently, a new field of study is emerging, called hybrid quantum information processing that combines the two conventional approaches to complement each other. In this talk, I will present generation of non-Gaussian quantum states of multimode light based on the hybrid quantum information processing. Squeezed vacuum, which is employed in the continuous-variable approach, is a Gaussian state, which can be used to build a large-scale quantum system in a deterministic way. However, non-Gaussian features are required in some quantum protocols, especially to reach a quantum computation advantage. Single-photon subtraction used in the discrete-variable approach can provide the non-Gaussian characteristics. We have implemented a single-photon subtractor compatible with multimode Gaussian states and generated non-Gaussian multimode quantum states. The resulting non-Gaussian multimode quantum states will have broad applications for universal quantum computing, entanglement distillation, and a nonlocality test.