The Cosmic Dark Energy: the current status of theory and observation

The high-z type Ia supernova magnitude-redshift relation, large-scale structure of galaxies, and the cosmic microwave background observations suggest that the expansion rate of our universe is currently under acceleration. Especially, our cosmological framework demands the presence of substantial amount of dark energy with repulsive nature like the cosmological constant. In this talk I briefly review several dark energy models that have been proposed so far and summarize the current status of dark energy model constraints with astronomical observations, together with my recent research works on this issue.

Massive (> 10,000 solar mass) young star clusters and OB associations dominate the energetic feedback from stars into the interstellar medium. They contain the most massive and luminous stars in the Galaxy, which shape their environments through winds, ionizing flux, radiation pressure, and eventually supernovae, destroying natal molecular clouds and inflating superbubbles. We develop a method, based on differential extinction of the Galactic disk, to search for massive star clusters powering most luminous star forming complexes in the Galaxy identified in the WMAP foreground maps. As results, we identify 25 candidate clusters within 40 star forming complexes having extinctions consistent with their distances. One notable example is the discovery of the Dragonfish association which is the most luminous OB association in the Galaxy powering a giant nebula at 10 kpc across the Galactic plane. Using near-infrared spectroscopy, we identify two Luminous Blue Variable candidates, one Wolf-Rayet, 15 O-type stars (including one possible runaway) out of 50 sampled stars located within the boundary of this association, which is consistent with the expected total number of OB stars greater than 400. The mass of the Dragonfish association is 100,000 solar mass, similar to that of Westerlund 1 known to be the most massive star cluster. These results, hence, offer an important opportunity to study the formation and evolution of most massive star clusters. We will discuss ongoing and planned follow-up observations of these new massive star clusters as well as the development of Wide Integral Field Infrared Spectrograph which is ideal to study them.

The night sky appears to be quiet and stable, but in reality many explosive events are happening in the universe every night. Such events are now being caught efficiently with recent transient surveys, and rapid follow-up observations are revealing exciting nature of these explosive events. In this talk, we present our follow-up observation activities of interesting transient events. These studies cover a wide range of astronomoical events including Swift J1644+57, the moment of a supermassive black hole devouring a star, the Chirstmas burst, a peculliar GRB caused by a death of two stars colliding in a common envelope, and GRB 071025, an explosive stellar death at z ~ 5 which reveals the existence of SN-dust in the early universe. In addition, we also present our work on a very nearby supernova in M101 galaxy which occured very recently. These and future transient events will continue to show us fresh views of the universe.

I will talk about Akdeniz University which is one of the magnet university in Turkey for scientist and students because of its location, infrastructure and intellectual capacity. Then introduce technical capacity of Antalya Technopolis and opportunity for co-operation. Also I will discus about recently established Department of Space Sciences and Technologies and our projects such as establishing 4 meter infrared telescope.

Space provides to mankind experimenting on extreme limiting conditions that are not possible on Earth. Therefore, one of the peaceful application of space technology is its usage on improving science in general, specifically space sciences itself. Since capacity building for a country cannot be done without being aware of the current status in general. This presentation aims to present basic astronomy and space sciences research and education in Turkey.

ALMA's unprecedented sensitivity and angular resolution at millimeter and submillimeter wavelengths will undoubtedly advance the vast frontiers of our knowledge about the universe. I will present expected impacts of ALMA on the studies of star and planetary system formation, in addition to the introduction of its basic capabilities. The sensitivity of ALMA to the optically thin thermal dust emission located at a nearby star forming region 100 pc away is as small as 1/100 of the earth mass in its beam size of ~1 AU, more than 100 times in sensitivity and 30 times in resolution than the currently available radio interferometers. ALMA is also expected to achieve an angular resolution of 0.1 arcsec or better for line observations, revealing detailed kinematics related to planet formation in disks. With such superb capabilities expected for ALMA, I will discuss fundamental questions of star and planetary system formation that we hope to answer with ALMA.

세종은 독자적으로 한양을 중심으로 한 자주적인 역(曆)을 편찬하도록 했다. 역을 편찬하는데 가장 기본이 되는 것은 태양, 달, 오행성, 항성들의 위치를 관측하고 또한 정밀한 시간을 측정해 하늘의 움직임을 정확히 계산해 내는 것이다. 세종은 1432년부터 본격적인 천문기기 제작을 시작했는데 이는 주로 이천과 천재 기술자 장영실이 맡았다. 특별히 천문기기 제작은 고대의 이상적인 성군(聖君)으로 성왕(聖王)이라 추앙받는 요(堯)와 순(舜) 임금이 했듯이 단지 천문학적인 행위만이 아니라 제왕 된 자가‘하늘을 받드는 정치’를 함에 무엇보다 먼저 앞서서 행해야할 중요한 사안으로 태평성대를 이룬 요순의 뜻을 받드는 옛 제도(古制)를 처음 회복한 것이다. 드디어 1433년 경복궁 안에 높이 9.4m 길이 14.4m의 거대한 천문대인 간의대(簡儀臺)를 세우고 청동을 부어 간의(簡儀)를 만들어 설치했다. 간의대 서편에는 24기(氣, 절기)를 측정하는 높이 8m 길이 25m의 규표를 설치했다. 세종은 종합 천문대인 간의대 주변에 간의의 구조와 기능을 개선하여 조선의 실정에 맞게 다목적 기능의 소형의 각종 관측기기인 소간의, 일성정시의와 앙부일구, 현주일구 등 각종 해시계를 창제하였다. 그 외에도 혼의혼상(혼천의와 천구의)각과 자격루와 옥루 등의 자동화를 구현하는 첨단적인 시설을 갖추어 실로 경복궁을 조선의 첨단 과학기술의 연구 시설을 만들었다. 세종 시대 간의대를 비롯한 천문시설들의 창제품들은 당대로서는 세계 최대 규모로 오늘날 인정받고 있다. 15세기 조선의 천문학이 세계적인 수준에 이른 것은 중요한 국책사업으로 적극적인 지원과 축적된 전통과학 기술, 창조적 재능을 지닌 학자와 장영실 같은 기술자가 있었기에 가능했다. 세종 당시 제작한 천문의기들 중 현존하는 유물은 단 하나도 없는 아쉬움이 있지만 최근 문헌 연구를 바탕으로 설계와 작동모델의 복원연구를 통해 다수 복원을 수행하였다. 그러나 아직도 세계적인 창제물인 옥루와 혼의혼상각 등 주요 유물들은 연구단계에 머무르고 있다. 지금까지 수행한 복원연구를 통해 세종시대 천문의기의 특성과 앞으로 복원방향을 제시하고자 한다.

Active galactic nuclei (AGN) are among the most powerful sources of radiation in the universe. As far as we understand today, their source of energy is accretion of matter into supermassive black holes with millions to billions of solar masses. AGN and their most prominent features - jets - are easy to observe in radio. I present results of a long-term monitoring program of luminous AGN covering timelines of 14 years. We find strong variability even on timescales of many years. From the emission statistics we conclude that the properties of AGN emission are more complex than commonly assumed.

Planet formation takes place rapidly in the disks around young stars. In order to understand the process, we must understand the nature and evolution of the youngest stars, the physics of the protoplanetary disks, and the formation timescale and properties of the exoplanets themselves. I will report on current research in my group on all three aspects of the problem using infrared imaging and spectroscopy, including observations and modeling of young stars and their disks, direct observations of young, very low mass objects, and radial velocity searches for young planets. The new IR spectrographs being built jointly by KASI and UT, IGRINS and GMTNIRS, will be decisive in revealing the details of planet formation. I will discuss some of the ways in which these instruments will move us from the era of discovery to one in which we can gain a quantitative understanding of planet formation.

1. The NASA Virtual Research Insititute : These innovative organizations are designed to be responsive to changing needs and to link NASA with the academic science community. Institutes are virtual, distributed networks of scientists, managed and directed by NASA. The NASA Astrobiology Institute pioneered in cross-disciplinary science in the new field of astrobiology, the study of life in the universe. The NASA Lunar Science Institute supports NASA science and planning for future human exploration of the Moon. 2. Near Earth Asteroids: Risks & Opportunities : Small Earth-approaching asteroids are stepping stones on the human exploration path to Mars. But they also pose a risk of catastrophic impacts with Earth. Either way, they are an important part of our cosmic neighborhood.

I make use of [alpha/Fe] ratios derived from SEGUE spectra of 17,277 G-type dwarfs to separate them into likely thin- and thick-disk subsamples, and investigate the rotational velocity and eccentricity gradients with metallicity, [Fe/H], distance from the plane, |Z|, and Galactocentric distance, R. Some of the notable findings are that there is a rather strong rotational velocity gradient of -20 to -30 km/s/dex with [Fe/H] for the thin-disk population, and +40 to +50 km/s/dex for the thick-disk population. The rotational velocity decreases with |Z| for both disk components, with similar slopes (-9.0 +\- 1.0 km/s/kpc). A relatively strong gradient of orbital eccentricity with [Fe/H] (about -0.2/dex) is observed for the thick-disk stars, whereas the eccentricity is independent of [Fe/H] for the thin-disk subsample. The shapes of the eccentricity distributions for the thin- and thick-disk populations remain roughly unchanged with |Z|. Comparison with several contemporary models of disk evolution indicates that radial migration seems to have played a vital role in the evolution of the thin-disk population, but probably less so for the thick disk, relative to the gas-rich merger or disk heating scenarios. I emphasize that more physically realistic models and simulations are required to perform detailed quantitative comparisons.

Do submillimeter galaxies trace out the most massive dark matter halos at high redshift? Mounting evidence suggests that submillimeter galaxies are the most massive gas-rich systems at redshift z~2-3 with far-infrared luminosity of 10^12-10^13 L_Sun. To answer the question, however, the statistical and large-scale properties of submillimeter galaxies are required. We have used the AzTEC 1.1 mm-wavelength camera and the Atacama Submillimeter Telescope Experiment (ASTE) 10-m telescope to perform a wide-field extragalactic survey. We have mapped ~3 deg^2 regions on the sky and revealed more than 1000 millimeter sources, resulting in one of the largest millimeter surveys to date. In the first half of this talk, I introduce the ASTE project. In the latter half of this talk I will highlight recent findings of our deep 1.1-mm survey of submillimeter galaxies. I will also share with you recent development of instruments, especially a new mm/submm bolometer camera which makes use of TES technology and is to be installed on ASTE in early 2012.

The last phase of stellar evolution from the asymptotic giant branch (AGB) to proto-planetary nebulae, to planetary nebulae represents the most active period of synthesis of organic compounds in a star’s life. Both inorganic and organic molecules and solids are found to form in the circumstellar envelopes created by stellar winds. Over 60 gas-phase molecules, including rings, radicals, and molecular ions have been identified by millimeter-wave and infrared spectroscopic observations through their rotational and vibrational transitions. Infrared spectroscopic observations of emissions from the stretching and bending modes of aliphatic and aromatic compounds have revealed a continuous synthesis of organic material from the end of the AGB to proto-planetary nebulae, to planetary nebulae. These results show that complex carbonaceous compounds can be produced in a circumstellar environment over a period of only a few thousand years. Most interestingly, there are a number of unidentified emission features which are almost certainly carbonaceous in nature but their exact chemical composition is unknown. These include the 21 and 30 micron emission features, and the extended red emission observed in proto-planetary nebulae and planetary nebulae. Spectroscopic signatures of the stellar organics show strong similarity to the insoluble organic matter found in meteorites. Isotopic analysis of meteorites and interplanetary dust collected in the upper atmospheres have revealed the presence of pre-solar grains similar to those formed in evolved stars. This provides a direct link between star dust and the solar system and raises the possibility that the early solar system was chemically enriched by stellar ejecta with the potential of influencing the origin of life on Earth.

As surveys of galaxy populations at high redshifts progress, it becomes increasingly urgent to understand how observed galaxies at high redshift map into those at lower redshift. In this talk, I investigate how and where stellar mass builds up over cosmic time by showing recent studies of the changing star forming properties of galaxies as a function of stellar mass and environment from redshift three to present.

The Spitzer Survey of Stellar Structure in Galaxies (S4G) uses mid-infrared imaging with the Spitzer Space Telescope to trace the stellar structure in a large sample of over 2300 local galaxies. The images are very deep and cover a large area. I will describe the progress of the project, and present examples of scientific results being obtained, on topics as varied as galaxy morphology, dark matter, and cosmological disk formation. In this seminar, I will also briefly introduce the Astrophysical Institute of the Canary Islands (IAC) and its observatories on Tenerife and La Palma.

Mars Odyssey, launched on April 7, 2001, had been successfully conducting its mission, including the determination of the elemental composition of the surface of Mars and understanding of water ice distributions on Mars. Mars Odyssey Gamma?Ray Spectrometer (GRS) Suite has confirmed the presence of water ice at the north and south poles as well as fairly high hydrogen concentrations for parts of the equatorial regions. Mars Odyssey GRS results provided elemental maps of Mars and new findings of Mars including confirmation of an ancient ocean on Mars. SELENE?1 (KAGUYA) mission is known to be one of the most successful orbital missions in history. Recently KAGUYA GRS team published radioactive maps of the Moon, and other elemental maps are under investigation at present. Understanding lunar surface using GRS is important with respect to both unravel geological history of the Moon and obtain elemental maps of lunar surface regions. New era of lunar exploration after the Apollo programs has started already by several countries. KAGUYA GRS team is planning on its next challenging task on SELENE?2 Rover with a gamma?ray?neutron?X?ray (GNX) system for new surface investigation of the Moon. This presentation demonstrates a summary of Mars Odyssey GRS results, current status of KAGUYA GRS data analysis.

This seminar introduces the climatology, anomalies, turbulence, and storm-time disturbances in the Earth’s ionosphere. Many ionospheric phenomena are associated with the variation of ionospheric height and atmospheric composition. Plasma density is sensitive to those factors because the plasma loss rate is sensitive to the molecular gas (O2 and N2) number density which varies with height. Atmospheric winds induce electric fields and plasma motion along the magnetic field lines by which the ionospheric height varies. Neutral composition is variable with season and hemisphere owing to the variation of the solar zenith angle and the Sun-Earth distance. During geomagnetic storms, the solar wind and magnetospheric energy deposition into the polar atmosphere causes an expansion of atmosphere, and the increase of molecular gases in the ionosphere induces plasma depletion in high latitudes. In low and middle latitudes, the plasma density either increases or decreases by the effects of storm-induced winds and electric fields. The goal of this seminar is to help an understanding of the plasma-neutral interaction and its effect on the ionosphere.

최근 SKA(Square Kilometre Array), LSST(Large Synoptic Survey Telescope), LHC(Large Hadron Collider) 등 대규모의 과학 프로젝트에서는 폭발적인 규모로 대량의 데이터가 생산되어 이를 중심으로 과학 연구의 패러다임을 바꿀 것으로 예상되고 있다. 이를 위해서는 대용량 데이터의 관리 및 전송을 위한 하드웨어 및 소프트웨어 기술의 발전이 수반되어야 하며, 대규모 데이터의 분석을 위한 유연하고 확장성 있는 컴퓨팅 시스템이 또한 필요하게 된다. 최근 각광을 받고 있는 클라우드 컴퓨팅은 인터넷을 기반으로 IT 자원 및 소프트웨어 등을 서비스 형태로 제공하게 하는 기술이다. 클라우드 컴퓨팅은 가상화 기술을 활용하여 자원의 유연성을 제공하고 활용성을 높이며 사용자 환경의 다양성을 제공할 수 있는 특징이 있다. 이러한 클라우드 컴퓨팅의 장점은 산업체의 IT 서비스를 넘어서 과학 계산 응용을 위한 서비스에도 적용될 수 있다. 클라우드 컴퓨팅은 기존의 고정된 시스템에서 지원하기 힘든 다양한 요구의 과학 연구를 지원할 수 있는 유연성과 확장성 등의 특징으로 인해 이미 여러 분야에서 클라우드 컴퓨팅의 장점을 살려 과학 연구를 지원하기 위한 노력을 하고 있다. 본 발표에서는 과학 응용에 클라우드 컴퓨팅 기술을 적용하려는 활동에 대한 최근 동향에 대해서 소개하고 현재 KISTI에서 수행하고 있는 사이언스 클라우드 연구에 대해서 소개하고자 한다.

Taking advantage of the superb capabilities of Chandra and XMM-Newton, during the last decade we have dramatically increased our knowledge on various aspects of the galaxy formation and evolution. I will review recent results on early-type galaxies based on X-ray observations, including both diffuse hot gas and point sources (stellar binaries and AGNs). In particular, I will focus on (1) the X-ray luminosity function of los-mass X-ray binaries, (2) X-ray scaling relations between the physical quantities of the hot ISM (LX and TX) and those of galaxies (LK, ?*), and (3) metal abundances and abundance ratios of the hot ISM. I will further address the implications of X-ray observational results, e.g., star formation episodes, dynamical and chemical evolutionary states of hot gas in early-type galaxies.

The talk is composed of two topics; one is about Ultra-High Energy Cosmic Rays (UHECRs) and the other is about Supernova Remnants (SNRs). As for the UHECR part, first I will present simulations of propagation of UHE-protons from nearby bright galaxies taking account of extra-galactic magnetic fields and galactic ones. Next I will present numerical study on the propagation of UHE-Nuclei in a cluster of galaxies. Finally, I will discuss the possible contributions of past Gamma-Ray Bursts in Milky Way to the spectrum and composition of UHECRs around/below 3E+19eV. As for the SNR part, I will discuss our motivation to study SNRs, what we have done for the study of supernova explosion and explosive nucleosyhtnesis, and what we plan to do for the study of supernova remnants. Some preliminary results of our SNR study are also presented.

.

According to the current paradigm of cosmological structure formation, the observable large scale matter distribution arose via gravitational amplification from tiny primordial density fluctuations. Especially modern numerical simulations reveal that cold dark matter aggregates to form a filamentary cosmic web consisting of huge empty regions, the so called voids, filaments and clusters. Hence, precision analysis of three dimensional large scale structure (LSS) data will help us to identify and understand the physical processes governing cosmological structure formation leading to a more complete theoretical picture of our Universe. However, contact between theory and observations cannot be made directly, since observational data is subject to a variety of systematic effects and statistical uncertainties. Most notably of those are the survey geometry and selection effects as well as statistical noise. Mapping the three dimensional matter distribution in the Universe thus requires accurate statistical data analysis methods. In my talk I will present new full Bayesian data analysis methods designed to provide detailed cosmographic descriptions of the large scale structure in the Universe while accounting for all observational uncertainties. As a result these methods provide sampled representation of the LSS posterior distribution, which enables us to report any desired statistical summary such as mean, mode or variance of the density field. Application of our method to the latest Sloan Digital Sky Survey data lead to the generation of detailed cosmographic maps for the three dimensional matter distribution and the possibility to accurately quantify its significance. These results permit a variety of following scientific projects to analyze the clustering behavior of matter in the Universe. In summary, the presented methods provide an efficient and flexible basis for high-precision LSS inference.

.

Debris from asteroids and comets continually bombards the Earth. Impacts by big bodies launches ejecta on trajectories that transports it thousands of kilometers from the impact site. These events are recorded in discrete layers of sub-millimeter size spherules in sea floor sediments. Larger, rarer, and interestingly shaped objects are found on land. I will describe the physical processes that occur in energetic impacts. Emphasis will be given to the mechanisms that determine the sizes and shapes of the ejecta and the cooling of the fireball. An analogy with structure formation in the expanding universe will be exploited, and a possible relation to the origin of chondrules will be explored.

Stars more than about 10 times the mass of the Sun are responsible for creating most of the heavy elements in the universe, for governing the evolution of galaxies, and quite possibly for re-ionizing the universe a few hundred million years after the Big Bang. The formation of these stars can be understood as an extension of the theory of low-mass star formation, generalized to include the effects of interstellar turbulence. However, a major problem must be overcome: For massive stars, the outward force due to radiation pressure exceeds the inward force due to gravity; how can gas accrete onto the protostar in that case? Circumstellar disks, outflow cavities, and radiative Rayleigh-Taylor instabilities all contribute to the solution of this problem. These conclusions are validated by means of 3D radiation-hydrodynamic simulations of high-mass star formation. The effects of ionizing radiation and variations in metallicity are also discussed. Observational predictions include (1) Massive stars should form in cores with surface densities of order 1 g cm^-2; (2) the stellar initial mass function (IMF) should follow the mass function of cores in the host molecular cloud, scaled down by a factor of a few; (3) and massive, turbulent disks detectable by ALMA, the EVLA, and large IR telescopes should occur around massive protostars.

스마트그리드와 관련하여 스마트그리드의 정의, 스마트그리드의 추진 배경, 스마트그리드로 인한 주요 변화, 스마트그리드 국가로드맵을 간략히 소개하고 현재 제주도 구좌읍 일대에서 진행 중인 스마트그리드 제주실증사업에 대하여 자세히 소개하고자 합니다.

태양 플래어는 태양 표면에서 일어나는 가장 강력한 폭발 현상이다. 태양 플래어에 부수되어 일어나는 여러 가지 현상은 지구와 지구 주위를 돌고 있는 많은 인공위성에 있는 장비들에게 위험을 제공할 수 있다. 그러므로 태양 플레어가 일어나는 원인과 현상을 잘 이해할 필요가 있다. 태양 플레어의 발생이 무작위적인 것이 아니고 그 발생하는 시간에 주기성이 있는 것이 발견되었다. 이런 주기들은 25.5일의 정수배로서 25.5일이 근본 주기인 것을 암시한다. 이러한 태양의 주기성은 무엇에 기인하는 것일까? 태양 플래어가 일어나는 장소도 무작위 적인 것이 아니고 어떠한 특정한 장소에 더 자주 일어나는 것이 발견되었다. 이 두 현상 간의 관계는 무엇일까?

See attached file

Located on the summit ridge of Mauna Kea, the Canada-France-Hawaii Telescope (CFHT) offers a suite of excellent instruments which benefit from the exceptional qualities of its site. With wide-field imaging cameras in the visible and near-infrared, a high-resolution spectro-polarimeter, and natural guide star adaptive optics capabilities, the current instrumentation and associated reduction pipelines allow CFHT to be one of the leading observatories of today’s astronomy. Queued service observing and remote operations make for very efficient operations leading to excellent data and exciting science. New instruments are in development to offer even more possibilities to its users’ base, which now reach beyond the three communities of its namesake to include Taiwan, Brazil, and recently China. CFHT is also preparing the redevelopment of its facility, studying the option of building an 8- to 10-m class telescope dedicated to wide-field multi-object spectroscopy. As exemplified by its many achievements, CFHT strongly believes in the virtue of joining forces to achieve much more than anyone would have achieved alone. This talk will give us a chance to interact and exchange ideas on a potential involvement of Korea in the current and future activities of the observatory.