學術演講及專題研討

Weak lensing has been shown to be a powerful tool for cosmology. In this talk, I will present a new model to study weak-lensing peaks, which contain rich non-Gaussian information. Based on a probabilistic approach, our model performs "fast simulations" to predict peak counts. This is based on two hypotheses: first, unbound and diffuse matter contributes little to peak abundance, and second, halo spatial correlation has a minor influence. The prediction carried out by our model is in a good agreement with N-body simulations, whereas the computation time has time largely reduced. I will highlight that our model can discriminate between various combinations of cosmological parameters, and that its high flexibility makes the use of peak counts under realistic survey conditions feasible.

The 3-year, high-cadence PS1 Andromeda survey yields well-sampled light curves that improve our understanding of microlensing and variables in M31. As a preliminary study, we discover 6 microlensing events in the inner bulge of M31. This demonstrates that deep data with good temporal resolution are essential to reveal microlensing events. We also explore the data for variability studies, and produce catalogs of ~300 eclipsing binaries, ~2000 Cepheids and other variables. We select bright eclipsing binaries for spectroscopic follow-up, to obtain a direct distance estimate of M31. We astromatrically align the multi-band Panchromatic Hubble Andromeda Treasury (PHAT) data to our PS1 images, and derive precise period-luminosity relation (PLR) for the Cepheids. The accurate distance and precise PLR will render M31 a distance anchor and help to reduce the error budget of Hubble constant. To fully exploit the value of PAndromeda, we welcome external collaborators, and can provide PS1 light curves with linked HST photometry upon request.

Gamma-ray bursts (GRBs) are one of the most energetic explosions in the universe, and can be observed across a wide range of wavelengths (from radio to GeV). Therefore, GRBs provide a rich environment to study astrophysics and a unique probe of cosmology, particularly the early universe. Swift, a multi-wavelength telescope dedicated to GRB study, marks its 10-year anniversary on Nov. 20, 2014. To date, Swift has discovered ~ 920 GRBs, within which ~ 315 GRBs have redshift measurements, ranging from z=0.03 to z=9.38. Here we focus on the Burst Alert Telescope (BAT) onboard Swift, the instrument that is responsible for triggering GRB detections. We present summaries of the BAT-detected GRBs for the past ten years, including temporal and spectral analyses of prompt emission and rest-frame properties. In addition, we perform searches for GRB emission beyond the event data (conventional data range for GRB analyses) using the BAT survey data, and report a list of GRBs with confirmed extended emission.

The Planck Telescope has made an accurate full-sky measurement of the cosmic microwave background (CMB) temperature, the leftover heat from the Big Bang. These measurements probe both the physics of the very early universe and the basic properties of the universe today. The Planck measurements confirm the earlier results from the WMAP telescope and rigorously test our standard cosmological model and provide an accurate determination of basic cosmological parameters (the shape of the universe, its age, and its composition). When combined with other astronomical measurements, the measurements constrain the properties of the dark energy and the nature of dark matter. The observations also directly probe the physics of first moments of the Big Bang: the current data are consistent with the idea that the early universe underwent a period of rapid expansion called inflation. Many key cosmological questions remain unanswered: What happened during the first moments of the big bang? What is the dark energy? What were the properties of the first stars? Dr. Spergel will discuss the role of ongoing and future CMB observations and describe how the combination of large-scale structure, supernova and CMB data can be used to address these key cosmological questions.

When I started using SMARTS to observe galactic novae nearly 12 years ago, little did I know how challenging and engrossing this endeavor would prove. After all, the "nova problem" has been solved many times, and the novae have been thought to be almost fully understood. This could not be further from the truth. Novae, thermonuclear runaways on the surfaces of white dwarfs, explode and interact with their environments on timescales of days to years, which is ideal for synoptic monitoring with the SMARTS facilities at CTIO. After an introduction, I will discuss what high-cadence optical and near-IR photometry tells us about the formation of dust in novae. But photometry only tells part of the story. I shall focus on high-cadence high resolution optical spectroscopy of two disparate novae, the recurrent nova V745 Sco and the slow nova V1369 Cen. High spectral resolution reveals never-before seen details which likely will permit us to map the circumstellar environments of the long-period symbiotic systems like V745 Sco. V1369 Cen put on a show over Christmas 2013. Like other slow, dust-forming novae, it had multiple optical outbursts. Each of these corresponds to the appearance of a new spectroscopic absorption system. Nearly-daily observations for 5 months let us trace the dynamics of the envelope, and perhaps to view dust formation. In the past most novae have been ignored once they faded; long-term synoptic photometry and spectroscopy are showing that the novae are far more complex than we had assumed, but appropriate observations can and are revealing new truths about these "new stars".

The detection of gravitational waves from the early universe would have a profound impact on our understanding of the early universe and would have an important implications for our understanding of fundamental physics. The BICEP2 team recently claimed to have made the first detection of gravitational waves. I will suggest that polarized dust is a more likely explanation and discuss the recent results from the Planck satellite. I will then look forward to upcoming experiments that will use multi-wavelength data to search for gravitational waves.

The Yuan T. Lee Array for Microwave Background Anisotropy, or AMiBA, is a radio interferometry array for cosmology experiments. It consists of 13 co-planar, dual-polarization receivers operation at 3 mm wavelength. Its backend is a 4-lag, analog correlator covering a baseband bandwidth of 2-18 GHz, but with almost no spectral resolution capability. The 7-element AMiBA was dedicated in 2006, and subsequently upgraded to the full 13-element Array in 2010. The full array operations has continued for four years and finally ended by 2014. In this talk, I will report on the AMiBA’s current status, particularly on the development of the wide-band digital correlator. This development has enabled new capability for the Yuan T Lee Array, and is preparing the instrument for new research in cosmology science. I will show you the recent testing results of a 4-station digital correlator, and our plan for a new science endeavor to understand the physics during the Epoch of Re-ionization using the Yuan T. Lee Array.

The Local Universe provides an excellent laboratory for studying the detailed processes of star formation and galaxy evolution. In this seminar, I will present some recent highlights from my work on blue early-type galaxies. Our latest model demonstrate that the observed "Green Valley" can be reproduced by two star formation truncation pathways for the evolution of galaxies. We previously found that the local post-starburst galaxies occupy a well-defined region in the low-mass end of the "Green Valley" and that even though star formation has only recently turned off, their morphology already resemble those of the low-mass red sequence galaxies. Since the post-starburst population is far too evolved, we probed the atomic gas content of its predecesssor population, namely, the blue early-type galaxies to search for the smoking gun that caused the sudden truncation of star formation. Our pilot study suggest that a kinetic process (probably AGN feedback) is driving the quick truncation of star formation in these systems, rather than a simple exhaustion of gas supply. In this talk I will also briefly describe some early results from the Radio Galaxy Zoo project.

Where are globular clusters forming today? Not in our Galaxy; none of the protoclusters in the Milky Way is likely to survive as a bound cluster. The candidate proto-globulars in the nearby Universe are the optically hidden, deeply embedded super star clusters in starburst galaxies, where hundreds or thousands of OB stars form in volumes less than a few parsec across. Star formation eficiency (SFE) in these sources is 40 − 70%, more than an order of magnitude greater than in our Galaxy; why so high? OB stars create energetic feedback that will work to disperse the cluster: how do the clusters survive, and what do they do to the surrounding clouds? We report on SMA observations that may show how to drive high SFE, and infrared spectra of metal lines with true resolution of 3 − 5 km/sec that trace the kinematics of the ionized gas and its interaction with the ambient molecular material.

Serpens South is an embedded cluster discovered by Spitzer. Its unique characteristic is the high fraction of Class 0/I objects, indicating that this cluster is just formed within 0.5Myr. Thus, Serpens South is an ideal object to study early phase of cluster formation. Based on our multiple molecular line data(N2H+, CCS, ...), we propose that cluster formation triggered by collisions of dense filaments whose dynamics is controlled by globally ordered magnetic field. We further propose a scenario that dense filaments are formed in the course of large-scale cloud-cloud collision. Cloud-cloud collision is probably one of the leading mechanism for triggering cluster formation.

The spectral energy distribution of the light emitted from galaxies across the electromagnetic spectrum contains a myriad of details about the stellar, nebular and dust components of galaxies. In the first part of the talk, I will present a new comprehensive library of galaxy spectra built by combining the semi-analytic post-treatment of a large cosmological simulation with state-of-the-art models of the stellar and nebular emission and attenuation by dust. A main novelty of our approach is the ability to interpret simultaneously the stellar and nebular emission from galaxies, even at low spectral resolution. In the second part of the talk, I will show how we can use this spectral library to constrain the physical parameters and star formation histories of low- and high-redshift galaxies. The results show us that simple declining functions of time are not always good approximations of the star formation histories of galaxies. Our approach can be used to extract valuable information from any kind of galaxy observation across the wavelength range covered by spectral evolution models as well as to plan for future galaxy observations.

The last decade has witnessed a revolution in tests of general relativity using binary pulsars. First, the discovery of the "double pulsar", PSR J0737-3039, has greatly improved the quality (and quantity) of tests of general relativity possible with double neutron star systems. In particular, it has greatly improved the famous test of the emission of gravitational waves, which was originally carried out with the Hulse-Taylor binary pulsar, PSR B1913+16. In this talk I review some of the basics on pulsars and neutron stars, discuss the basics of pulsar timing and discuss in detail these classical tests and their results, with a particular emphasis on the upcoming results from the double pulsar. Second, the discovery of several tight binary millisecond pulsar systems with optically bright white dwarf companions like PSR J1738+0333 and PSR J0348+0432 has allowed extremely constraining tests of alternative theories of gravity from the combination of radio pulsar timing and optical spectroscopy of the white dwarf companion. In this talk I discuss this new technique and present some of the results, their constraints on alternative theories of gravity, and future prospects for improvements. If time allows, I will also mention some of the constraints on violations of the local Lorenz invariance of gravity. In the last part of the talk I discuss future and more powerful tests of GR with pulsars. The first one is a test of the strong equivalence principle (SEP) using the new millisecond pulsar in a triple star system, PSR J0337+1715. The second is a very precise test of the no-hair theorem for black holes with a hypothetical pulsar orbiting the super-massive black hole at the center of our Galaxy.

Models of each stage of planet growth have mostly been successful at identifying the important physics in different regions of space at different times. The earliest stages are dominated by small-body physics, where sub-km-size bodies collide with each other and also interact with the gaseous solar nebula. Later, the gravitational interaction between planetary embryos on long timescales becomes more important. However, splitting the problem into different stages, each modeling subsets of the total physics, has an inherit weakness - planet growth does not progress at the same speed at all locations. Rather the inner regions of the Solar System may have many gravitationally interacting planetary embryos, while outer regions are still dominated by small-body collisions. Indeed, it has been recently shown that performing these simulations in a piecemeal way can lead us to fundamentally wrong conclusions about how the planets formed. Here we present simulations of planet formation from km-sized planetesimals all the way to planets. Using a particle-based code that models the fragmentation, accretion and dynamical evolution of a large number of planetesimals through the entire growth process we avoid the pitfalls of the classical piece-wise approaches. We generally find growth timescales that are far more dependent on distance from the Sun than previously expected. This leads to giant collisions between planetary embryos at 1 AU before Ceres-sized embryos have formed beyond 2 AU. We use these results to test classical models of Terrestrial Planet formation, including the recent Grand Tack model.

CMB measurements furnish to date the tightest constraints on the nature of the primordial fluctuations and, thereby, the physics of inflation. Interestingly, independent and competitive constraints can be obtained by measuring large scale density fluctuations in the low redshift Universe. I will describe recent theoretical and observational developments and show that, in the long run, large scale structure surveys may achieve limits on the primordial non-Gaussianity an order of magnitude better than Planck.

SEEDS is a strategic project in the Subaru telescope exploring exoplanets and circumstellar disks around 500 stars in the near-infrared wavelengths. The project has started in 2009 and will be completed in this year. Here, we review the project and summarize the major results especially in the survey of protoplanetary disks by near-infrared polarimetric imaging. In observing protoplanetary disks, we mainly focus on transitional disks known as a protoplanetary disk with a cavity in a central region of a disk. Disk-planet interaction would be one of intriguing interpretations potentially responsible for such a cavity-structure. Thus, transitional disks would be unique samples for understanding planet formation in a disk. As results of tens of observations in transitional disks, we have resolved fine structures in disks such as spirals, gaps, and dips at a radius of tens AU possibly due to gravitational interactions with unseen planet(s). These results may support planet formation at a wide orbit, e.g., GJ 504 b at 43 AU. We also found differences in structures of a cavity observed in the near-infrared and (sub-)millimeter wavelengths, i.e., a clear cavity in (sub-)millimeter wavelengths while no cavity in near-infrared wavelengths. The different behavior between small (sub-micron size) and large (millimeter size) dust grains would be consistent with disk-planet interaction plus dust filtration. Finally, we mention our preliminary results of disk demographics in transitional disks based on SEEDS data.

Finding the youngest protostars and proto-planetary disks and investigating their environment is a critical step toward fully understanding of star formation. In this talk, I will present the work my students and I have done on this subject. (1) Discovering a extremely young Keplerian disk around Class 0 protostar VLA1623A with SMA and ALAM data (Murillo et al, 2013), (2) Introducing "Multi-D" - a new method we developed for identifying faint YSO population in Giant Molecular Clouds using multi-band photometry data (Hsieh & Lai 2013), and (3) Molecular line observations showing that Very Low Luminosity Objects (VeLLOs) are most likely young protostars (Hsieh et al, 2015, in print).

The Large Magellanic Cloud, a satellite galaxy of the Milky Way, has been observed with the High Energy Stereoscopic System (H.E.S.S.) above an energy of 100 billion electron volts for a deep exposure of 210 hours. Three sources of different types were detected: the pulsar wind nebula of the most energetic pulsar known, N 157B; the radio-loud supernova remnant N 132D; and the largest nonthermal x-ray shell, the superbubble 30 Dor C. The unique object SN 1987A is, unexpectedly, not detected, which constrains the theoretical framework of particle acceleration in very young supernova remnants. These detections reveal the most energetic tip of a γ-ray source population in an external galaxy and provide via 30 Dor C the unambiguous detection of γ-ray emission from a superbubble.

Understanding the formation and evolution of galaxies remains among the foremost open problems in present-day astrophysics and cosmology. A reliable and detailed description of the density profile, mass budget, structural properties and stellar initial mass function of galaxies through cosmic time is a much-needed step forward but – whereas nearby systems have been subject to intense scrutiny – painfully little is known about more distant ones, since observational limitations make it challenging to employ the traditional diagnostic tools. I will demonstrate how these difficulties can be overcome by combining the information obtained from all the available constraints: strong gravitational lensing, extended stellar kinematics and stellar population synthesis modeling. This approach makes it possible to conduct unprecedentedly detailed and robust investigations of the dark and luminous structure of massive ellipticals beyond the local Universe and, for the first time, to put strong constraints on both the steepness and the elusive lower mass cut-off of their stellar IMF. Finally, I will discuss how this joint technique can take full advantage of present and upcoming state-of-the-art instruments in order to advance our understanding of galaxy structure at higher redshifts and beyond the current mass frontier.

The Stratospheric Observatory for Infrared Astronomy (SOFIA), is a highly modified Boeing 747-SP aircraft that has a 2.7-m telescope. Flying above more than 99% of the absorbing water vapor in the Earth's atmosphere, SOFIA provides access to otherwise unobservable wavelengths in the infrared to the worldwide astronomical community. SOFIA entered the Full Operations phase in February 2014, and is supporting observing proposals from astronomers all over the world. The project is an international collaboration between the US and Germany and has required high levels of coordination and communication among the many partners. The airplane has recently returned from an extensive periodic maintenance, and has resumed the science observation program. The plan for 2015 includes support for six science instruments, a deployment to the Southern Hemisphere, and support for an occultation of Pluto. This talk will cover some of the technical challenges in making SOFIA a reality, and will highlight some of the recent science results. Observing opportunities for Cycle 4 are described.

Polarization of the cosmic microwave background radiation is a powerful probe of the early universe. In particular, the so called B-mode polarization, a swirly spatial pattern in linear polarization, is a unique probe of primordial gravitational waves generated during inflation. After an overview of these concepts, I will give an update on the recent results from the BICEP/Keck experiments. These measurements made at the South Pole clearly detect a very significant B-mode signal at the relevant angular scales. Subsequent Planck high-frequency data, however, suggest that astronomical dust foregrounds could also produce a signal at this level. Regardless of existing uncertainties, I will argue that we are right at an important threshold of this exciting field. The recently deployed BICEP3 experiment will provide ground breaking sensitivity at a frequency that is much less affected by dust emission, using technologies and methodologies already vindicated by BICEP2 and Keck.

In this talk, I will briefly review the current status of global space technology and application, which focuses on the use of satellites and satellite launching capability. Analyses show that Taiwan is highly justified to develop space technology in terms of her strength in economy and military spending by sending satellites into orbit to serve its people for peaceful/economic purpose. I will also propose what Taiwan should do in the near future to cultivate its own niche space technology which will benefit economic and scientific development. These include nano/micro satellites in LEO and skim satellite in VLEO, among others. Then followed by brief introduction of history, classification and pros/cons of rocket propulsion technology. This explains why ARRC is currently devoted to developing hybrid rocket propulsion technology. Its role in future space exploration is also outlined. In addition, I will share some recent studies done by a joint work between Prof. Nick Thomas (University of Bern, Switzerland) and my group about gas/dust jet plume simulation of CG/67P comet which were recently rendezvous by Rosetta satellite launched by ESA.

By far, the most thoroughly observationally and theoretically characterized extrasolar planets are the class of short-period, highly irradiated, gas-giant planets. Though much of our understanding of atmospheric dynamics and planetary evolution is derived from solar system planets, observations and models of these exoplanets have suggested the dynamics of their atmospheres is dramatically different than anything within our own solar system. Their short-periods suggest that these planets are tidally locked to their host stars, resulting in extremely large longitudinal temperature gradients. Coupled to the planets rotation, this results in semi-static, supersonic jets that dominate all other dynamical features above pressures of several thousand bars. I will discuss the multiple aspects of these models utilizing 3D radiative hydrodynamical models coupled to a variety of models exploring jet formation, the formation of exotic clouds, and overall planetary evolution. Detailed ‘observations’ of our models allow us to both benchmark our models and predict future observations.

The Immersion Grating Infrared Spectrograph (IGRINS) is the first of a new generation of infrared instruments with high sensitivity, high spectral resolution, and very broad spectral grasp. IGRINS, a joint project of the University of Texas and the Korea Astronomy and Space Science Institute, has been in regular operation on the McDonald Observatory 2.7m telescope since 2014 September. It has a resolving power of 40,000 and covers the entire 1.4-2.5 micron range in a single exposure. Even though it is only on a small telescope, IGRINS has less than a factor of 2 less sensitivity than CRIRES on the VLT while having 30 times the spectral grasp. A main goal for IGRINS is to characterize the evolution of young stellar objects and their protoplanetary disks over their entire early lives with quantitative measures of photospheric and disk properties. High resolution spectroscopy allows us to measure T_eff, log g, magnetic field, v sin i, veiling vs. wavelength, accretion rate, and other properties across a range of pre-main sequence stages with a common technique. We will present some of the early results from the instrument and describe the programs under way to meet our goal.

Milky Way is a typical barred spiral galaxy and is one of few galaxies where we can resolve the stellar populations. A thorough understanding of the Galaxy provides strong clues how other spiral galaxies form and evolve. However, our picture of the Milky Way is far from complete with many of its basic parameters remain ill determined. I will review some recent progress on the photometric and dynamical modelling of the Milky Way bar, and discuss future prospects in the field.

Gas-rich galaxy mergers provide a means to funnel gas into the central region of the system, consequently triggering episodes of nuclear star formation and supermassive black holes growth. The details of the fueling and feedback are often obscured by the cocooning dust stirred up from the violent interaction. To probe the small-scale gas kinematics in the inner kiloparsec region of these local luminous infrared galaxies requires high spatial resolution observations of their nuclei. Here I present results from our Keck Adaptive Optics near-infrared integral-field survey of the nuclear regions in 17 late-stage galaxy mergers. Our findings characterized and addressed the nature of nuclear disks, outflows driven by AGN and starbursts, as well as the role of mergers in black hole-galaxy bulge scaling relations. Our observations further enabled several case studies showing direct evidence of biconical molecular outflows as well as shocked gas from winds and ISM collision between progenitor galaxies.

Cosmological inflation, which is the leading hypothesis to resolve the problems in the Big Bang theory, predicts that primordial gravitational waves were created during the inflationary era. Measurements of polarization of the cosmic microwave background (CMB) are known as the best probe to detect the primordial gravitational waves. POLARBEAR is designed to measure CMB polarization with an array of TES bolometers. It has been in operation since 2012 in the Atacama desert in northern Chile. The main scientific objective of POLARBEAR is to search for primordial gravitational waves imprinted as the “B-mode” in the CMB polarization maps. Another important goal is to measure a spatial distortion of the CMB polarization maps due to gravitational lensing, which is a very sensitive probe for the large-scale distribution of matter in the early universe and will constrain the sum of neutrino masses. The Simons Array is an expansion of the POLARBEAR. It will consist of an array of three 3.5m telescopes each coupled to a multichroic TES bolometer pixel, so that it will provide very powerful foreground rejection capability and much deeper observation. Finally, LiteBIRD is a satellite project to map CMB polarization over the full sky at large angular scales with ultimate precision. The LiteBIRD proposal was submitted to JAXA in February 2015 with the target launch in Japanese fiscal year 2022. The scientific objective of LiteBIRD is to test all the representative inflation models that satisfy single-field slow-roll conditions and lie in the large-field regime. To this end, the requirement on the precision of the tensor-to-scalar ratio, r, at LiteBIRD is equal to or less than 0.001, a hundred times better than the current constraint.

Dust is a key component of the interstellar medium (ISM) of galaxies. Dust grains form primarily in the ejecta of the stars. The two main sources of dust are the winds of low-to intermediate mass (< 8 Msun) stars and the rapidly evolving high-mass stars (> 8 Msun). In our Milky Way Galaxy, low-mass stars mainly dominate the injection of dust into the ISM during the asymptotic giant branch (AGB) phase. But the origin of dust in galaxies in the very early universe is controversial. The observed high abundance of dust in galaxies in the early Universe has often been taken to imply that rapidly evolving, high- mass stars are an important dust source. To quantify the dust properties (e.g. mass, composition), I analyzed the spectral energy distribution (SED) of a sample of Luminous blue variables (LBVs) and B[e] supergiants in the Large Magellanic Cloud (LMC). For this purpose, I have used spectroscopic and photometric observational data from Spitzer Space Telescope and Herschel Observatory. I computed the model spectra of these stars by using radiative transfer code MCMax. From the best fit models, I derived the time-averaged dust mass-loss rates of these high-mass stars and compared with the dust mass-loss rates of low-mass AGB stars. Based on this analysis, I speculate that high-mass stars are an important dust source in the ISM of the LMC and further detailed investigation is required.

ESO is an intergovernmental organisation for astronomy founded in 1962 by five countries. It currently has 14 Member States in Europe with Brazil and Poland poised to join as soon as the respective Accession Agreements have been ratified. Together these countries represent approximately 30 percent of the world’s astronomers. ESO operates optical/infrared observatories on La Silla and Paranal in Chile, partners in the sub-millimetre radio observatories APEX and ALMA on Chajnantor and has started construction of the Extremely Large Telescope on Armazones near Paranal. La Silla hosts robotic and national telescopes as well as the NTT and the venerable 3.6m telescope. The former had a key role in the discovery of the accelerating expansion of the Universe and the latter hosts the ultra-stable spectrograph HARPS which is responsible for the discovery of many of the confirmed exoplanets with masses below that of Neptune. On Paranal the four 8.2m units of the Very Large Telescope, the Interferometer and the survey telescopes VISTA and VST together constitute a unique integrated system which supports 16 powerful facility instruments, including adaptive-optics-assisted imagers and integral-field spectrographs, with half a dozen more on the way and the 39m Extremely Large Telescope with its suite of instruments to be added in less than ten years. Scientific highlights include the characterisation of the supermassive black hole in the Galactic Centre, the first image of an exoplanet, studies of gamma-ray bursts enabled by the Rapid Response Mode and milliarcsec imaging of evolved stars and active galactic nuclei. The single dish APEX antenna, equipped with spectrometers and wide-field cameras, contributes strongly to the study of high-redshift galaxies and of star- and planet-formation. Early results obtained with ALMA demonstrate its transformational potential for high-resolution, high-sensitivity observations of the cold Universe, near and far. The colloquium will provide an overview of ESO’s current programme, with emphasis on recent increases in observing capabilities, consider ESO’s role in the broader context of astrophysics, and will briefly touch on opportunities for the future.

Current developments in the astrophysics of stellar mass compact objects will be highlighted. Recent space based and ground based observations of X-ray point sources in our Galaxy and in external galaxies have led to a resurgence of interest in these objects. A brief overview of their observational properties will be introduced and our current physical understanding described. Many of these objects are transient, exhibiting time variations in both flux and spectra. By studying their behavior in both quiescence and in outburst, they can be used as cosmic laboratories to reveal the physics underlying their nature and state of evolution.

Comets are the best sample of primitive solar nebula material presently available to us, dating back 4.57 billion years to the origin of our planetary system. Past missions to comets have all been “fast flybys”: They provided only a snapshot view of the dust and ice nucleus, the nebulous coma surrounding it, and how the solar wind interacts with both of these components. The Rosetta mission was set for a much more ambitious challenge - to accompany a comet nucleus on its journey around the Sun, monitoring the evolution of its activity, and deploy a lander on its surface. Rosetta is an ESA mission, with contributions from member states and from NASA, and it currently orbits the Jupiter family comet 67P/Churyumov-Gerasimenko (67P). After rendezvous on August 2014, the Rosetta spacecraft moved from 100 km above the nucleus to a bound orbit only ~10 km away. This early period of the mission has revealed previously unseen details of a comet nucleus, as Rosetta's instruments recorded measurements that were once impossible. After delivering the lander on November 2014, Rosetta began the systematic characterization of the nucleus and the monitoring of its activity, using a complex trajectory pattern offering complementary observation conditions. We review in this talk the knowledge acquired by the Rosetta mission so far.

The New Horizons spacecraft has spent the past nine years sprinting across the solar system to meet up with Pluto in July 2015. Even at this point, a few months out from the flyby, New Horizons is already returning images of Pluto as good or better than anything previously obtained. The spacecraft carries instruments covering ultraviolet, visible, infrared, and radio wavelengths to make surface and atmospheric observations of Pluto and its moons, and dust and particle instruments to study Pluto's environment and interaction with the solar wind. In this talk I will describe the mission and instrumentation, what we currently know about the Pluto system and the Kuiper belt, and what we hope to discover in the next few months at Pluto and the next few years as New Horizons passes through this "third region" of the solar system and possibly has another close encounter with a Kuiper belt object.

The commissioning phase of the Gaia satellite was completed in July 2014 and we are well into the first year of routine phase operations out of the nominal 5 year mission. All subsystems are working and the operational parameters have been tuned for optimum science performance. A final upgrade of the on-board detection software is under testing. The aim is to be operational in the final configuration by summer 2015. The magnitude limit of the survey has been set to G=20.7 mag for astrometry and photometry. The spectroscopy magnitude limit is currently G_RVS=16.2 mag, but may be adjusted pending the new on-board software testing. The Science Alerts stream based on photometry has been started while preparations are underway for the first intermediate catalogue release by summer 2016. Examples of Gaia observations will be shown to indicate the scientific power of this ESA cornerstone mission.

Most stars in our Galaxy form in clusters which often contain massive (M>8 Msol) stars which, with their prodigious energy output, eventually dominate the evolution of the interstellar medium. Understanding how these clusters and the massive stars within them form and evolve is one of the key questions for astrophysics. A major challenge is identifying the clumps of dense gas in molecular clouds which give rise to these clusters before the feedback from 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 data including observations with ALMA, 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.

Dust obscuration has hidden at least half of the cosmic accretion activity and concealed the most intense sites of star formation during the peak epoch for both processes in galaxy evolution at 1 < z < 3. Centimetric radio interferometry is the only means of identifying the AGNs and tracing star-forming activities at sub-arcsecond resolution, in an extinction-independent manner. I will discuss the use of radio survey to study star formation and AGN at 1 < z < 3, focusing on the early results from two ultra-deep 4-8 GHz Jansky VLA (JVLA) radio observations at 0.3" resolution in the UDS and HUDF fields. The goals of these surveys are to combine the radio data with the existing panchromatic observations to produce a complete census of AGN and to spatially resolve the star-forming galaxies. The ongoing survey in the HUDF, in particular, will reach 0.3 microJy/beam RMS and will provide the definitive radio dataset for spatially-resolved, ultra-deep, broadband extragalactic studies until the SKA era.

Life’s origin was one of the biggest riddles remained for us. Since 1950s, a large number of laboratory experiments and theoretical consideration have been made to solve it. The standard scenario of the origins of life today is as follows: (1) Organic compounds such as amino acids were formed in primitive Earth environments or delivered from space, (2) further chemical evolution toward the first life system occurred in the primitive ocean. In addition, the possibility that life itself was delivered from space, now referred to as panspermia hypothesis, should also taken into account. However, the relics of the first life as well as organic compounds used for the first life were not remained in the present Earth. In these days, it becomes possible to find such relics in extraterrestrial environments. Primitive organic compounds in comets and asteroids can be directly studied through space missions. Titan, the largest moon of Saturn, may reserve some relics of chemical evolution in its atmosphere and liquidosphere. Mars and some other solar system bodies may cultivate life systems different from terrestrial one. In the colloquium, possibilities to find relics of chemical evolution in space will be introduce, as well as the results of laboratory experiments simulating chemical evolution in primitive environments.

On-going and future galaxy surveys are going to reach sub-percentage accuracy on the cosmological measurements, e.g., Baryon Acoustic Oscillation, redshift-distortion, etc. A robust methodology is required while reaching such precision. Any minor systematic error from observations, data analysis, or theoretical models might be not negligible for future surveys. I would like to introduce the current methods, point out the potential systematics, and discuss the solutions.

The global star formation law — the relation between gas and star formation rate (SFR) — is studied in a large sample of 181 local galaxies with infrared (IR) luminosities (SFR) spanning almost five orders of magnitude. The surface density of dense molecular gas (as traced by HCN) has the tightest and linear correlation with that of SFR. We further show that the SFR and a variety of dense gas tracers (HCN, CS, their high-J, high-J CO) are all linearly correlated for both the Galactic dense cores in our Milky Way and star-forming galaxies near and far. This has immediate implications on the modes of star formation in galaxies and suggests that dense cores are the basic units in contributing to the star formation and the SFR might depend linearly upon the mass of dense molecular gas (the dense gas star formation law). These ground-based observations of last decade and recent Herschel results highlight what the ALMA can deliver on the studies of star formation laws at all redshifts and on all scales.

From keV electrons in terrestrial aurorae to Ultra High Energy Cosmic Rays in unidentified "Zevatrons", the cosmos shows a plutocratic proclivity to concentrate energy in a tiny minority of suprathermal particles. The particle acceleration mechanisms involved can be traced back to the ideas of Faraday, Fermi and Alfvén though we are learning that the details are idiosyncratic and much can be learned from comparing and contrasting particle acceleration in laboratory and cosmic locations. Special attention will be given to acceleration accompanying strong shock fronts, spinning, magnetized compact objects and a new, general mechanism called “magnetoluminescence”.

Observations of the isolated globule B335 with ALMA have yielded absorption features against the continuum that are redshifted from the systemic velocity in both HCN and HCO+ lines. These features provide unambiguous evidence for infall toward a central luminosity source. Models of inside-out collapse from an isothermal sphere can match the observed line profiles of HCN and HCO+ averaged over the central 50 AU.

A black hole accretion is necessarily transonic. In presence of sufficiently high viscosity and cooling effects, a low angular momentum transonic flow can become a standard Keplerian disc except close to the hole where it must pass through the inner sonic point. However, if the viscosity is not high everywhere and cooling is not efficient everywhere, the flow cannot completely become a Keplerian disc. We show that, in agreement with the theoretical solutions of viscous transonic flows, matter having the viscosity parameter above a critical value becomes a Keplerian disc while matter having lesser viscosity remains a low angular momentum, sub-Keplerian flow. Thus, for instance, a flow having sufficiently high viscosity on the equatorial plane and low viscosity above and below would produce a two-component advective flow where a Keplerian disc is surrounded by a rapidly infalling sub-Keplerian halo. We find that the post-shock region of the relatively cooler Keplerian disc is evaporated and the overall configuration is quite stable. This agrees with the theoretical model with two components, which attempts to explain the spectral and timing properties of black hole candidates.

Compact binary coalescences (CBCs) are the most promising gravitational wave source for the LIGO/Virgo detectors. We predict the detectable rate of CBCs from short GRB observations, and constrain the GRB beaming angles from the non-detection of mergers in existing LIGO/Virgo data. The gravitational wave signals are almost impossible to obscure via dust absorption or other astrophysical processes, allowing us to derive the universal distribution of signal-to-noise ratios (SNR) for gravitational wave detection. This distribution guarantees the existence of high SNR events, and these provide the best constraints on source parameters such as sky locations. We discuss low-latency localization from these high SNR CBC detections, and some preliminary work on optimizing EM follow-up of CBC sources.

Luminous Infrared Galaxies (LIRGs) are observed primarily to be interacting and merging galaxies. They are the sites of rampant star formation and active galactic nuclei (AGN) which are fed by abundant supplies of molecular gas. However, the very property that led to their initial discovery by IRAS as a significant galaxy population - their high infrared luminosity - also makes them difficult to study; the majority of the UV and optical light from young, massive stars and AGN is absorbed by obscuring dust and re-emitted in the infrared. The Great Observatories All-sky LIRGs Survey thus makes use of the diversity in wavelength coverage of the present space-based telescopes to probe the activity in a large (~ 100 - 200), flux-limited sample of LIRGs from the Revised Bright Galaxy Sample (RBGS). The first part of the talk will be devoted to discussing the survey as a whole. The latter part of the talk will be focussed on how our VLA and Herschel Space Observatory surveys are helping to shape the picture of star formation in extreme environments.

Clusters of galaxies are among the largest gravitationally-bound objects in the Universe, and are found at the intersections of the large filamentary structure known as the Cosmic Web, which connects them to other clusters and superclusters. Clusters therefore trace the large-scale spatial distribution of dark matter, and can be used in cosmological tests that are independent from, and complementary to, other probes such as the cosmic microwave background (CMB), supernovae, and baryon acoustic oscillations (BAO). One tool now being used to find clusters at high redshift is the Sunyaev-Zel'dovich effect (SZE), which has redshift-independent surface brightness. To accurately extract cosmological parameters SZE observations, one must better understand how the signature due to thermal pressure tracks the gravitational potential, or more generally: How well does the baryonic component trace dark matter? The Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO) is a 2-mm (150 GHz) 128-element bolometer array that operated from the IRAM 30-meter Telescope, providing a resolution of 16.5''. In a handful of follow-up observations, it was able image the SZ decrement in high-redshift massive clusters. Newly-built, the 2nd generation, dual-band GISMO-2 instrument will double its 2-mm pixel count, providing 256 detectors with lower instrument noise than the original GISMO. Additionally, GISMO-2 will simultaneously image the SZ increment and mm-wave sources with 1280 detectors operating at 1.2 mm (250 GHz). I will present GISMO SZ imaging of a few massive high-redshift clusters, and discuss prospects for GISMO-2 in combined studies using the 2nd generation MUltiplexed SQUID/TES Array at Ninety GHz (MUSTANG-2) from the 100-meter Green Bank Telescope.

In this talk I will present new SIGAME simulations of the [CII] 157.7um fine structure line emission from cosmological smoothed particle hydrodynamics (SPH) simulations of main sequence galaxies at z = 2. The gas in our galaxy simulations is modelled as a multi-phased interstellar medium (ISM) comprised of molecular gas residing in the inner regions of giant molecular clouds, an atomic gas phase associated with photodissociation regions at the surface of the clouds, and a diffuse, fully ionized gas phase. Taking into account heating by the local FUV radiation field and cosmic rays - both scaled by the local star formation rate density - we calculate the [CII] emission from each of the aforementioned ISM phases. The [CII] emission peaks in the central (<~ 1 kpc) regions of our galaxies where the star formation is most intense, and we find that the majority (>~ 60%) of the emission in this region originates in the molecular gas phase. At larger galactocentric distances (>~2 kpc), the atomic gas is the main contributor to the [CII] emission (>~ 80%), and at all radii the ionized gas provides a negligible amount (<~ 5%) to the [CII] budget. Our simulations predict a log-linear relationship between the integrated [CII] luminosity and star formation rate with a slope (0.80 +/- 0.12) in agreement with observationally determined slopes (~ 0.85 - 1.00) but with a ~ 3 times higher normalization than the observed z ~ 0 relation.

Strong gravitational lenses are useful for probing dark matter and cosmology. Gravitational lenses are rare and present significant challenges to find. Current algorithms are not efficient enough in finding lenses automatically. Better techniques are critical for discovering lenses from ongoing and planned large imaging surveys. Understanding the selection function of the lens samples is required for doing statistical studies. I will talk about Space Warps, a citizen science project to find strong gravitational lenses. I will discuss how the system works and how we determine the completeness and purity of our lens samples. The first lens search in Space Warps was done with the CFHT Legacy Survey (CFHTLS) data. I will present the results from this search.

An overview of the current status of the NRAO Central Development Laboratory will be presented. Future development plans on MMIC amplifiers, Phased Array Feeds, Integrated Receiver Development, and CDL's role in the future ngVLA and ALMA development will also be discussed.

During the past few years, the SMA has been engaging in a wideband receiver upgrade. Front‐end receivers with IF bandwidth of 12+ GHz have been introduced. Most of these receivers employ series distributed SIS mixers fabricated in ASIAA. Later this year, we will be introducing a new set of receivers that cover 210‐270 GHz, which can be operated together with the existing 200 or 300 GHz receiver sets. At the same time, a new digital backend, the SWARM correlator, is being developed and put into action. Powered by the 5 GSample/sec Analog‐Digital Convertor developed by ASIAA, SWARM currently offers 2 x 1.5 GHz bandwidth, in addition to the 2 x 2 GHz provided by the ASIC (or legacy) correlator. This wideband receiver upgrade has improved the sensitivity of the SMA. Under good weather conditions, the SMA can deliver a detection threshold of 1 mJy or better at 345 GHz with the ASIC correlator alone. Further gains are being materialized when the SWARM data is included. Looking beyond the current phase of receiver upgrade, we believe that the sensitivity of the SMA can see further improvements. Our vision for the Next Generation Receiver System for the SMA includes a combination of re‐formulation of the front‐end hardware, coupled with a continued expansion of the backend digital hardware. In order to achieve this objective, the entire receiver system has to be overhauled. We are drawing up plans to achieve this, with the aim of targeting specific areas of science that the SMA is best positioned to do well. We will present our plans, and we hope to get inputs from both the technical and scientific groups in ASIAA, which have strong interests in the continued operation of the SMA.

The newly established luminosity functions (LFs) of high-z galaxies at z ~ 4 - 10 can provide a stringent check on dark matter models that aim to explain the core properties of dwarf galaxies. The cores of dwarf spheroidal galaxies are understood to be too large to be accounted for by free streaming of warm dark matter without overly suppressing the formation of such galaxies. In this talk, I will show from cosmological simulations that wave dark matter, ΨDM, appropriate for light bosons such as axions, does not suffer this problem, given a boson mass of m ~ 10^{-22} eV. The large-scale structure of ΨDM is indistinguishable from cold dark matter (CDM), as desired, but differs radically inside galaxies where quantum interference forms solitonic cores surrounded by extended halos of fluctuating density granules. The halo mass function is suppressed below ~ 10^10 M⊙ at a level that is consistent with the observed high-z LFs and the Thomson optical depth recently reported by Planck. Moreover, ΨDM predicts that the LFs should turn over slowly around an intrinsic UV luminosity of M_UV ≥ -16 at z ≥ 4, distinctly different from CDM. We also show that for galaxies magnified >10x in the Hubble Frontier Fields, ΨDM predicts an order of magnitude fewer detections than CDM at z ~ 10 down to M_UV ~ -15, allowing us to distinguish between these very different interpretations for the observed coldness of dark matter.

The observational scrutiny of the atmospheres of exoplanets is now a legitimate field of inquiry, which has motivated their theoretical study. In this review talk, I will summarise and highlight the state of the art of both observations and theory of exoplanetary atmospheres. The review is organised into eras, starting from the birth of spectrophotometry to the upcoming set of next-generation exoplanet hunters and characterisers. On the observational side, I will review spectrophotometry, phase curves, eclipse mapping, direct imaging and ultra-high-resolution spectroscopy. On the theoretical side, I will review atmospheric radiation, chemistry and circulation (fluid dynamics). I will discuss the problem of bright stars and why we need the next-generation of exoplanet hunting machines (CHEOPS, TESS and PLATO) to build up a better target list for atmospheric characterisation. Finally, there will be a discussion of the habitable zone and also how the conversations between the scientists from different sub-disciplines need to be more constructive.

Orbital resonances play a major role in the distribution of small bodies in our Solar System, and almost certainly in other planetary systems. They sometimes serve as traps, and in other situations are a rapid source of instability. This talk will present a primer on orbital resonances and then discuss the resonant populations present in our Kuiper belt. The resonance dynamics in the Kuiper belt is complex but is yielding its secrets to careful survey work, like the Outer Solar System Origins Survey (OSSOS) running on CFHT via a joint Canada+France+Taiwan team. Some of the selection effects in outer Solar System surveys will be illustrated, which need to be understood for projects like LSST. The early Solar System processes which created these resonant populations will be outlined, providing a window into planetary formation and evolution.

The cosmic microwave background (CMB) is a powerful tool for cosmology, encoding a wealth of information about the universe's history and structure. In particular, precision CMB polarimetry has long held the promise of revealing the physics of inflation through a minuscule "B-mode" imprint that is imparted by primordial gravitational waves. I will discuss our current knowledge of CMB polarization, and I will describe a new instrument, SPIDER, that aims to characterize the inflationary B-mode signal with high sensitivity and fidelity. SPIDER is a balloon-borne telescope that launched from McMurdo Station, Antarctica on January 1, 2015, and successfully observed for 16 days. I will discuss the preliminary in-flight performance and prospects for the science analysis.

The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a proposed array of 1024 cheap 6m dishes that has received preliminary approval from the South African NRF. The main goals of HIRAX include measurements of Baryon Acoustic Oscillations at redshift 0.8-2.5, searching for new pulsars and radio transients, and discovery of new neutral hydrogen absorbers. Preparations for HIRAX include the development of a new pipeline to search for Fast Radio Bursts (FRBs), which are some of the most enigmatic things in the sky. They burst incredibly brightly (~10 Jy) for a millisecond, never to be seen again, and their origin and even distance (and hence energy scale) is completely unknown. We have run the trial pipeline on 650 hours of suitable GBT data looking for FRBs. We present an overview of HIRAX and preliminary results from the FRB search.

The near-Earth asteroids (NEAs) are a population of objects on orbits around the Sun that pass near or cross that of Earth. They are probes of solar system history, accessible targets for spacecraft missions, and a potential hazard to life on Earth. Ground-based radar observations with large radio telescopes provide the extremely accurate astrometry and trajectory predictions for near-Earth asteroids. They also provide detailed information on the shapes, spin states, and surface properties of a large number of objects; giving essential context for spacecraft missions to asteroids. I will describe the techniques of planetary radar astronomy and review the capabilities of radar observations from the Arecibo Observatory, the Goldstone Deep Space Network site, the Green Bank Telescope, and the Very Long Baseline Array. Then I will detail the physical properties of a few asteroid radar targets; including Toutatis, visited by the Chang'e 2 spacecraft in 2012, and Bennu, target of NASA's upcoming OSIRIS-REx mission.

We will present the dense molecular gas in the central regions of nearby Seyfert galaxies, focusing on the HCN(1-0) and HCO+(1-0) molecules which have been observed by Plateau de Bure Interferometer (PdBI). In one remarkable case, NGC 3079, we will discuss the origins and implications for the double blue-shifted absorption lines. We combine our new data with similar observations in the literature to create a sample of 8 Seyferts with comparable data. In 7 of these, the emission line kinematics implies thick disk structures of 50-100pc scales, suggesting such structures are a common occurrence. We find a relation between the circumnuclear HCN luminosity and dynamical mass that can be explained by a gas fraction of ~10% and a conversion factor of ~10. Adopting a different perspective to probe the physical properties of the gas close around AGN, we report on an analysis of molecular line ratios which indicates that the clouds in this region are not self-gravitating. Finally (if it still has time), we will briefly introduce the current status of Swift-BAT AGN large program.

The Atacama Large Millimeter/submillimeter Array (ALMA) is an aperture synthesis interferometer that currently operates from wavelengths of 3 mm to 350 microns with up to sixty six (66) array elements: fifty four (54) of 12-m diameter and twelve (12) of 7-m diameter. The array is located at the ALMA Array Operations Site (AOS) on the Chajnator plateau (at an altitude of about 5000 meters) in the Atacama desert in northern Chile. While the antennas and most of the hardware for the receivers are on site, array capabilities are still expanding and the observatory is ramping up towards full operations. Early science observations have been ongoing since October 2011 and ALMA started the fourth cycle of Early Science observations. Many exciting, fundamental results have already been obtained. I will review the current status of the project, the array performance, testing, and development projects and present a selection of some of the most exciting scientific results from the solar system to the early universe. In short, I will present ALMA: past, present and future.

What is the nature of dark energy and dark matter? I will describe two astronomical experiments based on strong gravitational lensing that can address this question in a novel way. In the first experiment, strong gravitational lenses where the background source is variable in time and the foreground deflector is a massive galaxy are used as cosmic "standard rods". I will illustrate recent advances in modelling techniques and data quality that enable a 6-7% measurement of constraints on distance from a single gravitational lens. I will show that results from just two systems yield constraints on the equation of state of dark energy and flatness comparable to those obtained with the best probes. The second experiment uses the flux ratios between multiple images of gravitationally lensed quasars to detect the presence of dark subhalos independent of their stellar content. This tests a fundamental prediction of the cold dark matter model, i.e. that galaxies should be surrounded by large numbers of dark satellite subhalos. Proof that such satellites do not exist would force a revision of the model in favor of more exotic alternatives like warm dark matter. I will show first results from this experiment based on Keck-Adaptive Optics observations. I will then conclude by discussing the bright prospects of studies of the dark sector using gravitational lensing.

The Grism Lens-Amplified Survey from Space (GLASS) is a large HST cycle-21 program targeting 10 massive galaxy clusters with extensive HST imaging from CLASH and the Frontier Field Initiative. The program consists of 140 primary and 140 parallel orbits of near-infrared WCF3 and optical ACS grism observations, which result in spatially resolved spectroscopy of thousands of galaxies. GLASS has three primary science drivers although a wide variety of other science investigations are possible with the public GLASS data (e.g. SN 'Refsdal'). The key science goals of GLASS are to: 1) shed light on the epoch of reionization, by measuring the lyman alpha optical depth at z>6; 2) Study gas accretion, star formation, and outflows by spatially mapping resolved star formation and determine metallicity gradients from emission lines of galaxies at 1.3

×