In this talk, the multi-core fiber Bragg gratings (MCFBGs) is introduced and it is shown how they can be used in the astronomical purpose. Furthermore, the current status of the MCFBG development will be presented. Fiber Bragg gratings (FBGs) are the most compact and reliable method of suppressing atmospheric emission lines in the infrared for ground-based telescopes. Standard single core FBG based filters (GNOSIS) were demonstrated in AAT to eliminate 63 OH lines in 2011 and in . Inscribing FBGs on multi-core fibers offers advantages. Compared to arrays of individual single mode fibers (SMFs), the multi-core fiber Bragg grating (MCFBG) is greatly reduced in size, resistant to damage, simple to fabricate, and easy to taper into a photonics lantern. AAT and the University of Sydney are developing the next generation of GNOSIS (PRAXIS). In addition, I would like to briefly introduce various instruments for the astronomical purpose in Astrophotonics group of AAO and the University of Sydney including an optical angular momentum (AOM) measurement as well as a microspectrograph (NanoSpec), which is the world’s first photonics-based spectrograph and have been developed to be shipped in a micro-satellite (i-Inspire). The i-Inspire has been tested in a weather balloon in 27 km altitude in 2012 and will be launched. The arrayed-waveguide-grating (AWG) based filter development will also concisely be presented.

This talk is a review of the current status of the luminosity function for broad-lined unobscured AGN, along with implications for triggering and black hole growth, and a look at the unresolved issues. It is inspired by the 50th anniversary in 2013 of Schmidt’s discovery of the nature of the quasar redshift to reflect on the state of knowledge and context of early determinations of the quasar luminosity function vs. those today. The rapid evolution of the high-z luminosity function holds some promise for differentiating the physical processes responsible for triggering ? mergers, “cold flow”, or instabilities within the hosts. More data are still needed, particularly to characterize the faint end of AGN activity.

Recent developments in CMB and large-scale galaxy surveys have led to the standard cosmological model, but the physical understanding of its ingredients remains elusive so far. In response to the gravity of these issues, numerous large-scale galaxy surveys are ongoing or planned to be operational in a near future. However, precision measurements in future galaxy surveys bring in new challenges, demanding substantial advances in theoretical modeling and observational methods. I will discuss the recent theoretical development in modeling galaxy clustering in a relativistic context and the observational issues associated with this recent development. The relativistic effect in galaxy clustering or the deviation from the standard Newtonian description becomes substantial on large scales, in which dark energy models or alternative theories of modified gravity deviate from general relativity, and in which the fingerprint of the inflationary epoch remains in its pristine form. I will discuss how the subtle relativistic effect in galaxy clustering can be used to test general relativity on large scales and probe signatures of the early Universe.

The existence of the dark matter has been strongly supported from the cosmological observations such as the stellar rotation curves of spiral galaxies and the CMB measurements. The origin and nature of the dark matter however remain largely unknown, which has been among the most active research avenues in both particle physics and cosmology. This talk will give a theoretical overview on the current status of the dark matter studies, along with the examples for the attempts to search for them from the high energy physics and cosmology experiments.

Crowded regions of the sky present a significant challenge for stellar photometry. I will discuss how we use difference-imaging to extract the signals from variable stars from the background of constant-brightness objects, and show some examples from the KMTNet microlensing survey of the Galactic Bulge. I will briefly discuss the use of Graphical Processing Units (GPUs) for parallel computations in astrophysics, and describe pyDIA, a new GPU-based code for wide-field difference-imaging photometry.

Stars are opaque, so how can we work out their interior structure and the physical processes that are occurring inside them? Asteroseismology is the science of deducing stellar interiors from observations of a star’s surface oscillations. By monitoring a star’s tiny surface vibrations with a precision spectrograph, we can calculate that star's unique frequencies and modes of vibration, which are wholly governed by its interior structure. In this way, we can obtain tight constraints on the conditions within the star, which allows us to probe the relationship between the interior structure and the evolution of stars. In this talk, I will describe our observing programme at the University of Canterbury’s Mt John Observatory, where we obtain extensive high-resolution echelle spectra of non-radially pulsating stars. We analyze these to obtain the pulsational frequencies and identify these with the multiple pulsational modes excited in the star. I will present a summary of our observational program and some recent results from our spectroscopic frequency and mode-identification analysis.

Intensity interferometry, based on the Hanbury Brown--Twiss effect, is a simple and inexpensive method for optical interferometry at microarcsecond angular resolutions; its use in astronomy was abandoned in the 1970s because of low sensitivity. Motivated by recent technical developments, we argue that the sensitivity of large modern intensity interferometers can be improved by factors up to approximately 25,000, corresponding to 11 photometric magnitudes, compared to the pioneering Narrabri Stellar Interferometer. Our approach permits the construction of large (with baselines ranging from few kilometers to intercontinental distances) optical interferometers at the cost of (very) long-baseline radio interferometers. Realistic intensity interferometer designs are able to achieve limiting R-band magnitudes as good as m~14, sufficient for spatially resolved observations of main-sequence O-type stars in the Magellanic Clouds. Multi-channel intensity interferometers can address a wide variety of science cases: (i) linear radii, effective temperatures, and luminosities of stars; (ii) mass-radius relationships of compact stellar remnants; (iii) stellar rotation; (iv) stellar convection and the interaction of stellar photospheres and magnetic fields; (v) the structure and evolution of multiple stars; (vi) direct measurements of interstellar distances; (vii) the physics of gas accretion onto supermassive black holes; and (viii) calibration of amplitude interferometers by providing a sample of calibrator stars.

In this colloquium, I am going to mainly talk on my recent work on the tidal disruption of stars by supermassive black holes, specifically how accretion disks are formed around spinning supermassive black holes in tidal disruption events. Since I am moving from KASI to CBNU soon, I would also like to talk on how to find evidences for binary supermassive black holes on sub-parsec scales in the context of the binary-disk interaction, which is another topic I have been working on with colleagues in KASI.

Giant Lyman-alpha blobs with sizes of 50-100kpc represent dramatic episodes of on-going galaxy formation in the distant Universe. Research in the past decade has struggled to make progress on the question of what powers these huge Ly-alpha halos and whether the Ly-alpha-emitting gas is outflowing or infalling. In this talk, I will overview the recent progress in the Lya blob research, mainly based on my own works. First, I will present our deep and/or large area narrowband imaging surveys to identify tens of Lya blobs at redshifts ~2-5. These surveys have produced the first constraints on blobs' clustering and large-scale environment, showing that Lya blobs occupy massive halos likely to evolve into rich groups and clusters today. Second, we carried out large optical/NIR spectroscopic campaigns to investigate their gas kinematics. Our studies using non-resonant (optically-thin) emission lines show that there are only *weak* outflows within the blobs, therefore gas infall or extreme hyper/superwinds are not the source of the extended Ly-alpha emission. I will also present the first detection of molecular gas from a Ly-alpha blob and our on-going effort to characterize the physical conditions of its ISM. Lastly, I will discuss how the future facilities (GMT and ALMA) will play a role in revealing the nature of this mysterious sources.

천문학 분야 중 가장 빠르게 변화하는 분야가 있다면 그것은 태양계일 것입니다. 왜냐하면 우리는 이미 많은 탐사 장비를 태양계 곳곳으로 보냄으로써 과거에는 알 수 없었던 태양계의 많은 정보를 얻고 있는 시대에 살고 있기 때문입니다. 21세기 우주탐사시대를 맞아 태양계는 다다를 수 없는 곳이 아닌 개척의 영역으로 변하고 있습니다. 그리고 멀지 않은 미래에 우리나라도 태양계 탐사에 동참하게 될 예정입니다. 이번 강연은 인류가 살아가게 될 제2의 지구를 찾는다는 작은 주제를 가지고, 현재까지 인류가 찾아낸 태양계의 여러가지 모습들을 살펴보고자 합니다.

In the local universe, it is well known that various properties of galaxies show a clear environmental dependence. Still, it is an open question when and how this environmental dependence was developed and shaped. In this presentation, I will address this intriguing question, showing our recent results on the build-up of passive galaxies over a wide redshift range, from z~2 to z~0.5, focusing on its environmental dependence.

One of the main goals of physical cosmology is to find out the actual model of the Universe. Current standard model of cosmology, also known as concordance model, is a spatially flat FLRW Universe consist of weakly interacting cold dark matter, cosmological constant and baryons considering power-law form of the primordial perturbation. While we can use the data to model or reconstruct different characteristics of the Universe such as its expansion history or the form of the primordial spectrum, considering the data limitations and its uncertainties we have to deal with cosmographic degeneracies that makes it difficult to distinguish between different models. On the other hand one can use the power of the data to falsify different aspects of an assumed model using advanced statistical techniques. In my talk I review these two strategic approaches, 'reconstruction and falsification', highlighting the importance of each one and how they are connected; focusing on the concordance model of cosmology and how we can falsify this model.

Observations show that the Universe is fully ionized by z~6. The LyC photons from dwarf galaxies have been suggested as the most promising source of reionization, but little is yet known about how they escape from their host dark matter halos. In this talk, I will discuss two mechanisms (supernova feedback and runaway stars) that regulate the escape fraction at the epoch of reionization (z>7) by using high-resolution, cosmological radiation hydrodynamics simulations with adaptive mesh refinement. We find that a rapid build-up and subsequent destruction of star-forming clouds by SNe allows for the LyC photons to escape efficiently (~10%) through low-density channels. Inclusion of runaway OB stars further enhances the fraction (~14%), but the total number of escaping photons is found to be similar due to more effective suppression of star formation in this case. Both models (SN or SN+runaways) predict that a sufficient number of photons escapes from the halo at z~7 to keep the universe ionized, as observed. However, a still larger amount of ionizing photons appears necessary at z>9 to accommodate the electron optical depth inferred from the CMB measurements. I will finish the talk by discussing two possible solutions to this problem.

Coalescing compact binaries are the strongest gravitational wave emitters detectable by latest network of ground-based detectors that are ready to make detections beginning this year. However, in order to effectively localize the source of a gravitational wave signal as well as determine the parameters of the source and its environment, an electromagnetic counterpart is necessary. At present, there is convincing evidence that short gamma-ray bursts (sGRBs) are emitted by a compact binary merger, rendering it a promising electromagnetic counterpart for an impending gravitational signal. In this light, this work focuses on black hole-neutron star (BHNS) mergers as a viable site of sGRBs. More specifically, the work seeks to understand the role of the magnetic field of the neutron star companion in generating an sGRB. We use numerical relativity to study the magneto-rotational instability (MRI) as a viable magnetic field amplification mechanism in a BHNS merger and determine the possible outcomes that will render a BHNS merger as a promising sGRB site. We find that a large-scale poloidal field, which is necessary to collimate an sGRB jet, is likely generated via the MRI in the outer regions of the accretion disk of the black hole remnant.

Development of ASIAA and the Future of EAO

Chile is widely recognized as the leading site for ground-based observational astronomy in the world, with many first-class facilities and a growing local research community. In an effort to promote bilateral collaborations in astronomy, the Chinese Academy of Sciences (CAS) has recently established an office in Chile to coordinate its programs. I will introduce the operations of this office and its recent activities, then discuss its long-term mission and the prospect of international cooperation in the Southern Hemisphere.

I will present the star formation work we have done at Universidad de Chile. Starting with the establishment of the Maipu radio observatory in the 1960s, radio-astronomy was the first modern astrophysical expertise developed in Chile, before the advent of modern telescopes in the north of Chile. The 1980s brought the establishment of the 1.2m Columbia telescope at CTIO for the Milky Way CO 1-0 survey, and later the SEST 15m telescope. Thus, we began the study of dense gas in star forming regions. The 2000s brought the high frequency regime with the advent of the ASTE and APEX telescopes and now high angular resolution with ALMA. I will explain some of the survey work we have carried with the above instruments and how it led to the discovery of landmark sources that we are studying now with ALMA. Finally, I will mention what we hope to accomplish with ALMA in the forthcoming decade, in particular with the establishment of the Chilean Virtual Observatory.

In this talk I will present numerical simulations of dynamically relaxed rotating dense stellar systems (e.g. Globular, Nuclear Star Clusters). Targeted are systems characterized by their long-term evolution (Gyr) and particularly, by the presence of initial axi-symmetry due to rotation. A central massive Black Hole is alternatively included, which grows due to consumption of stellar matter. Our models are compared to available observations of galactic rotating globular clusters, and is concluded that initial rotation significantly modifies the shape and lifetime of these systems. Recent simulations of clumped Dark Matter particles can reproduce the Galactic rotation curve over a Hubble time. The advantages of up-to-date high performance computing is discussed in this context.

Recent observations of sunspot's umbra suggested that it may be finely structured at a sub-arcsecond scale representing a mix of hot and cool plasma elements. In this study we will report the first detailed observations of the umbral spikes, which are cool jet-like structures seen in the chromosphere of an umbra. The preliminary analysis indicates that the spikes are not associated with photospheric umbral dots and they rather tend to occur above darkest parts of the umbra, where magnetic fields are strongest. The spikes exhibit up and down oscillatory motions and their spectral evolution suggests that they might be driven by upward propagating shocks generated by photospheric oscillations. We analyze sunspot oscillations using Interface Region Imaging Spectrograph (IRIS) slit-jaw and spectral data and narrow-band chromospheric images from the New Solar Telescope (NST). The intensity of chromospheric shocks displays a long term (about 20~min) variations. Data allowed us to conclude that sunspot umbral flashes (UFs) may appear in the form of narrow bright lanes running along the light bridges and surrounding clusters of umbral bright points. Time series also suggested that UFs preferred to appear on the sunspot-center side of light bridges, which may indicate the existence of a compact sub-photospheric driver of sunspot oscillations. The sunspot's umbra as seen in the IRIS chromospheric and transition region data appears bright above the locations of light bridges and the areas where the dark umbra is dotted with clusters of umbral dots. Co-spatial and co-temporal SDO/AIA data showed that the same locations were associated with bright footpoints of coronal loops suggesting that the light bridges may play an important role in heating the coronal sunspot loops. Finally, the power spectra analysis showed that the intensity of chromospheric and transition region oscillations significantly vary across the umbra and with height, suggesting that umbral non-uniformities and the structure of sunspot magnetic fields may play a role in wave propagation and heating of umbral loops.

Dark energy, the name given to the cause of the accelerating expansion of the Universe, is one of the most profound mysteries in modern science. Current cosmological models hold that dark energy is currently the dominant component of the Universe, but the exact nature of dark energy remains poorly understood. There are ambitious ground-based surveys underway that seek to understand dark energy and NASA is participating in the development of significantly more ambitious space-based surveys planned for the next decade. NASA is providing mission-enabling technology to the European Space Agency‘s (ESA) Euclid mission in exchange for US scientists to participate in the Euclid mission. NASA is also developing the Wide Field Infrared Survey Telescope-Astrophysics Focused Telescope Asset (WFIRST-AFTA) mission for possible launch in ?2023. WFIRST was the highest ranked space mission in the Astro2010 Decadal Survey and the AFTA incarnation of the WFIRST design uses a 2.4m space telescope to go beyond what the Decadal Survey envisioned for WFIRST. Understanding dark energy is one of the primary science goals of WFIRST-AFTA. I’ll discuss the status of Euclid and WFIRST and comment on the complementarity of the two missions. I’ll also briefly discuss other, exciting science goals for WFIRST, including a search for exoplanets using both microlensing and a dedicated coronagraph for exoplanet imaging.

Most stars in our Galaxy form in clusters which often contain the massive stars which, with their prodigious energy output, dominate the evolution of the interstellar medium. Understanding how these clusters and the massive stars within them form and evolve is one key questions for astrophysics. A major challenge is identifying the clumps of dense gas in molecular clouds which give rise to these clusters before star formation significantly modifies their properties. Infrared dark clouds (IRDCs), dense regions seen in absorption against the diffuse infrared emission in the Galactic Plane, are amongst the best candidates for identifying such objects. In this talk I will draw on IRDCs identified in a recent new catalogue, plus other recent data, to explore how the gas in molecular clouds gathers to form massive dense clumps and how these subsequently evolve as star formation takes place within them.

Galaxy clusters are the largest well defined objects in the Universe which form from density fluctuations originating from the early Universe. They are interesting large-scale astrophysical laboratories for the study of a wealth of phenomena on one hand, and their evolution and abundance represent an excellent probe to test cosmological models that can describe our Universe on the other hand. In the talk I will illustrate this potential of galaxy cluster research with three examples. X-ray observations of the intracluster medium allow us to probe the chemical composition of the intracluster medium, which contains more than half of the products of stellar nucleosynthesis. A comparison of the abundances of the most important heavy elements leads very roughly to a consistent picture with our theoretical understanding of supernova yields. The second example concerns the interaction of AGN jets at the center of clusters with the intracluster medium. This "AGN feedback mechanism" prevents the gas in the centers of clusters from catastrophic cooling. This well observed scenario in galaxy clusters has shaped the modelling of feedback effects in theoretical studies of galaxy evolution. Based on the largest X-ray galaxy cluster sample with a well defined selection function from the ROSAT All-Sky Survey we obtain measures of the large-scale structure of the Universe which allow us to test cosmological models. The parameters which are best determined by our survey are the cosmic matter density and the amplitude of the matter density fluctuations today. We discuss these results in context with other observational constraints of cosmological parameters. We also use the clusters to map the large-scale matter distribution in the local Universe.

Through KASI, Korean astronomers will have access to the Gemini Observatory starting in 2015. Gemini operates two optical/infrared 8m-class telescopes: one on the northern hemisphere in Hawaii, one on the southern hemisphere in Chile. Both are equipped with state of the art instruments and adaptive optics systems that will be presented. Gemini also offers the opportunity for instrument development, and welcomes visiting instruments. In Operations, Gemini offers to its partners three ways of applying for time: through semesterly calls for standard programs, through yearly calls for Large and Long Programs, and through monthly calls for fast turnaround programs. Gemini operates in queue mode (observing for the principal investigators and allowing flexibility in the time domain), as well as in the classical visitor mode (where principal investigators come to the telescope). The requirements and advantages of all these modes will be explained. The talk will review these topics and more to provide a full update on the Gemini Observatory.

Due to increasing size of astronomical data and expected boom of survey projects, it becomes important to detect interesting objects reliably in the large amount of data. I explain the importance of applying machine learning algorithms in future astronomical research. Focusing on application of clustering algorithms to detect groups in data, I introduce a non-parametric Bayesian clustering method and a consensus clustering method which improve reliability of detecting genuine variable sources in time-series astronomical data. I also present a new strategy of time-series data analysis to identify variable sources quickly by using ensemble of clustering methods as the data size grows. Possible applications of the non-parametric Bayesian method are presented for theoretical and observational astronomical research, emphasising the role of data-driven models.

The feedback from massive young stars has a profound impact on the interstellar medium (ISM), driving turbulence and regulating star formation. Among many feedback processes, supernovae provide predominant amount of momentum to the ISM in scales larger than individual star forming regions. In this talk, I will review our recent hydrodynamic numerical simulations in local galactic disks, including momentum feedback from supernovae. Our models demonstrate that the star formation rates are regulated to establish all thermal, turbulent, and vertical dynamical equilibria. In addition, synthetic HI 21cm emission and absorption lines constructed from our simulations successfully reproduce and explain the observed distribution of the brightness temperature, optical depth, and spin temperature. Finally, I will introduce our current attempt to quantify a necessary condition for the correct treatment of supernova feedback.

The International Astronomical Union (IAU) Office for Astronomy Outreach (OAO) is an IAU new office hosted at National Astronomical Observatory of Japan (NAOJ) at Tokyo. After the International Year of Astronomy 2009, IAU decided to establish the OAO to coordinate the international astronomical outreach efforts. Two major campaigns that OAO are running are the International Year of Light 2015 and the Public Naming of Exoplanets. IAU is one of the supporting organisation of the International Year of Light 2015 (IYL2015), and one of the IYL2015 cornerstone project is “Cosmic Light”, which connect astronomy to light. On the other hand, IAU has launched the NameExoWorlds campaign, to name exoplanets, however, using a different approach than the naming of solar system bodies like asteroids or comets, the naming of exoplanet will involve public voting and proposal nominations from public organizations.

In the first part of my talk, I will briefly introduce my research interests. I will talk about my works on the observations toward high-mass star forming regions. In the second part of my talk, I will focus on the follow-up observations toward Planck cold clumps with ground-based radio telescopes, which is becoming a large internationally collaborating project. Below is the brief introduction of this project. Stars form in dense regions within molecular clouds, called pre-stellar cores (PSCs), which provide information on the initial conditions in the process of star formation. The low dust temperature (<14 K) of Planck cold clumps/cores makes them likely to be pre-stellar objects or at the very initial stage of protostellar collapse. We have proposed follow-up observations towards these sources with ground-based telescopes (IRAM 30-m, PMO 14m, APEX, Mopra, Effelsberg 100 m, CSO, NRO 45-m and SMA). We will identify and characterize starless cores, prestellar cores and preclusters, and determine the evolutionary sequence for these cores and study their physical and chemical properties. We will also study the fragmentation of these starless Planck cold clumps to see whether the fragmentation in the earliest phase of star formation is determined by turbulence or not. This study will greatly improve our understanding of the initial conditions for star formation and core evolution. I will discuss the progress and the plans (e.g. ALMA) of this internationally collaborating project.

The first part of this talk will be the research highlights of my galaxy cluster studies. While I keep deep optical imaging campaigns on galaxy clusters, my research interests also have expanded into the environmental effect on galaxy evolution and the high-z galaxy clusters. Recent results and ongoing observational projects in which I am closely involved will be introduced. The second part will be a brief introduction to Astronomy in Chile. I would like to share my experiences of the research environment in Chile as a Chilean astronomer.

Beyond the local universe, neutral hydrogen (HI) gas, a tentative star formation reservoir, is poorly constrained by observation, compared to star formation. It is because existing observing facilities in radio frequency to detect HI 21-cm emission lines are not sensitive to directly measure weak HI signals from individual galaxies at z > 0.2. To overcome the sensitivity limitation, two new techniques have been proposed and recently proved their viability. One is HI spectral stacking technique, and the other is HI intensity mapping. These are the most promising techniques to push the sensitivity limit of even future radio facilities such as SKA pathfinders and SKA still further. In this talk, I will present how HI gas content of galaxies in the intermediate redshift 0.1 < z < 0.4 has been measured using the HI spectral stacking that I used in my previous works and briefly introduce an HI intensity mapping experiment which I am heavily working on at the moment.

The standard model of physics does not require the fundamental constants of nature (the FCs) to be constant in space and time. In the past, quests to measure possible variations have mostly been performed with atomic and also molecular hydrogen as well as metal absorption lines at (observer frame) optical wavelengths. At (sub)millimeter and radio wavelengths, in various cases dramatically different dependences of certain spectral lines on FCs allow for extremely sensitive constancy tests. Farthest back in time, to 12.8 Gyr, reach our recent sensitive limits on a combination of the fine structure constant and the proton-to-electron mass ratio, that we determined from sensitive measurements of emission from rotational CO and fine structure lines from atomic or ionized carbon toward high redshift (up to z = 6.4) quasar host galaxies. We shall briefly summarize these but shall concentrate on absorption line measurements, which are much more sensitive. At present, 5 (sub)mm- and/or radio-wavelength molecular line absorbers are known at cosmological distances, all at z < 0.9 and thus probing look back times up to about 7 Gyr. Three of these are the lensing galaxies of graviations lens systems. Observations of numerous different molecules toward on of these systems not only delivers the tighest cosmological limits on the proton-to-electron mass to date but also reveal a fasciating astrochemistry that is quite different from that of the Milky Way’s interstellar medium. We shall also provide an outlook on opportunities with the ALMA, the JVLA and the SKA.