Subaru Seminars

Astronomers now understand that exoplanets are abundant, and most stars may have planets. The most interesting exoplanets - the ones that are potentially habitable - are unfortunately very challenging to observe, and require optical systems that are radically different from conventional imaging telescopes. Over the last decade, I have been working with astronomers and optical physicists to develop and test such systems for both ground-based and space-based telescopes. I will describe how such systems work, and highlight a few major recent advances I have been involved in. I will illustrate the strong synergy between efforts in laboratories (mostly in support of future space telescopes) and the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) project on the Subaru telescope. I will show that much progress has been accomplished in the last few years, and that we can now foresee two short term strategies to image and study other habitable worlds: (1) a medium-size (~2 to 4-m diameter) space telescope equipped with a high performance coronagraph can image Earth-like planets around nearby Sun-like stars; (2) an extremely large telescope (ELT) can image habitable planets around nearby low luminosity (M-type) stars.

I have worked for Laser fusion for 20 years and devoted mainly on hydrodynamic instabilities and integrated code development for laser implosion physics [1]. Then, I was involved in the collaboration with supernova physicists to analyze the hydrodynamic instability of SN1987A. This led me to ``laboratory astrophysics'' to do a variety of model experiments on compressible hydrodynamics, atomic physics, plasma physics and so on the physics of which are expected to happen in the Universe. I aim at making plasma physics attractive for young scientists by providing challenging subjects of plasma physics in the laboratory astrophysics [2]. I am currently carrying out experiments of Astrophysics to model the structure formation of high Mach number collisionless shock observed in many supernova remnants, SNRs [3]. I demonstrated that the shock is formed by turbulent magnetic field produced by the nonlinear growth of the Weibel instability [4] in collaboration with about 20 groups in the world [5]. We will use the world-biggest laser NIF (National Ignition Facility) [6] for this experiment next year. In addition, I am working on the theory and computation of the vacuum breakdown [7]. Namely, at higher laser intensity about 1024 W/cm2 which is about two orders higher than the presently demonstrated one, we can efficiently convert laser energy to relativistic electron-positron plasma energy [8]. Such "plasma-QED physics" can model gamma-ray-burst, AGN jets, and many high-energy astrophysical phenomena. Finally it is noted that our activities are involved formally as Laboratory Astrophysics division (LAD) in AAS[9].

[Reference]

[1] H. Takabe, ``A historical perspective of developments in hydrodynamic instabilities, integrated codes and laboratory astrophysics'', Nuclear Fusion 44 S149-S170 (2004)
[2] H. Takabe, ``Astrophysics with Intense and Ultra-Intense Lasers``Laser Astrophysics'', Progress of Theoretical Physics Supplement 143, 202-265 (2001)
[3] TN Kato, H Takabe, ``Non-relativistic Collisionless Shocks in Unmagnetized Electron-Ion Plasmas'', Astrophysical Journal Letters 681 (2), L93 (2008)
[4] H. Takabe et al., ``High-Mach number collisionless shock and photo-ionized non-LTE plasma for laboratory astrophysics with intense lasers'', Plasma Physics and Controlled Fusion 50 (12), 124057 (2009)
[5] NL Kugland, ... H. Takabe and H. S. Park, ``Self-organized electromagnetic field structures in laser-produced counter-streaming plasmas'', Nature Physics, October 1 (2012)
[6] https://lasers.llnl.gov/
[7] Ruffini et al, Physics Reports 487, 1-140 (2010)
[8] C. P. Ridgers,Phys. Rev. Lett., 108, 165006 (2012)
[9] http://lad.aas.org/newsletter/newsletter_1_2012_09_10

Feedback of massive stars is vital to galaxy evolution and important in limiting ISM properties. In this talk, I will discuss massive star feedback mechanisms, such as radiation pressure and stellar winds, employing both theoretical approaches and observational studies. First I will discuss using the ionization parameter as a tool to assess feedback of radiation pressure in starburst galaxies, and HII region structures and their emission line spectra under the influence of radiation pressure and stellar wind feedback. I will then present the first fully calibrated molecular hydrogen emission image of the 30 Doradus Nebula. Molecular hydrogen emission is a key to quantify massive star feedback, and 30 Doradus is the nearest starburst region which allows detailed studies of ISM properties in starburst environments. This is the first time one has direct access to quantify energy feedback from massive stars and its origins with a tremendous amount of spatial details. I will argue that radiation pressure is an important feedback mechanism in starburst systems, whereas stellar winds are not likely as significant a feedback mechanism as previously suggested in the literature.

Galaxy clusters are the largest gravitationally bound systems in the universe and include the most massive galaxies in the universe; this makes galaxy clusters ideal laboratories for disentangling the nature versus nurture aspect of how galaxies evolve. Understanding how galaxies form and evolve in clusters continues to be a fundamental question in astronomy. The ages and assembly histories of galaxies in rich clusters test both stellar population models and hierarchical formation scenarios. Is star formation in cluster galaxies simply accelerated relative to their counterparts in the lower density field, or do cluster galaxies assemble their stars in a fundamentally different manner? To answer this question, I review multi-wavelength results on star formation in galaxy clusters from Coma to the most distant clusters yet discovered at look-back times of 10 billion years (z~2).

The ultra-faint dwarf galaxies (UFDs) are the least luminous galaxies in the Universe (10^3 < L < 10^7 Lsun). Their stellar populations are extremely old (~12-13 Gy), making them unique probes of low mass galaxy evolution at high redshift. Stellar chemical abundances play an important role in understanding UFD evolution, since they are a fossil record of the conditions of the gas when stars were formed. I will report on our ongoing study of the chemical abundances of alpha elements (Mg, Si, Ca, and Ti) in eight UFDs, using medium-resolution Keck/DEIMOS spectroscopy. Our data are consistent with a population of objects that underwent very inefficient star formation. I will also discuss our chemical abundance sample in the context of the formation of the Milky Way stellar halo.

We have developed a germanium immersion grating mid-infrared cryogenic spectrograph (GIGMICS) designed for the Nasmyth focus stage of NAOJ Subaru 8.2-m telescope, which operates at N-band (8-13 micron) in wavelength with maximum resolving power R~40,000. A single crystal germanium echelle immersion grating (30 × 30 × 72 mm) for collimated beam size of 28 mm (diameter) was fabricated by utilizing ultra precision micro-grinding method coupled with the ELID (ELectrolytic In-process Dressing) technique (Ohmori, H. 1992, Ebizuka et al. 2003, Tokoro et al. 2003). After the critical test for the application to the laboratory gas-phase IR high-resolution spectroscopy (Hirahara et al. 2010), we have conducted the “first light” astronomical observation of GIGMICS by the Kanata 1.5-m telescope at Higashi-Hiroshima Observatory from January to April, 2011. Toward many astronomical objects such as the Moon, Venus, Jupiter, circumstellar envelopes of late-type stars, proto-planetary nebulae, and interstellar molecular clouds in the vicinity of star-forming regions, we conducted spectroscopic observations in the N-band region. As a result, we successfully detected 24 lines of 12CO2 (v1, v2^l, v3, r)=(0, 1^1, 1, 1) <- (1, 1^1, 0, 1) and 11 lines of -13CO2 (0, 0^0, 1, 1) <- (1, 0^0, 0, 1) transitions in Venus. Among these two transitions, 13 lines were detected for the first time. Toward the planetary nebula NGC-7027, We detected [S IV] forbidden line (2P3/2->2P1/2) at 10.510 micron, and investigated the spatial distribution for the first time in the ground based spectroscopic observation.

The Infrared Array Camera (IRAC) on Spitzer Space Telescope has observed extended infrared emission associated with a number of young stellar objects and star forming regions. These are in many cases attributed to either shocks in molecular gas, scattered continuum in the outflow cavity, or PAH emission due to illumination by ultraviolet radiation. We present our recent studies of such emission, and show that such emission holds keys for understanding important issues for star formation: .e.g., driving and propagation of jet flows, evolution, circumstellar environments and the mechanism of mass accretion for high-mass protostars.

Understanding infrared (IR) luminosity is fundamental to understanding the cosmic star formation history and AGN evolution, since their most intense stages are often obscured by dust. Japanese infrared satellite, AKARI, provided unique data sets to probe this both at low and high redshift; the AKARI all sky survey in 6 bands (9-160um), and the AKARI NEP Deep survey in 9 bands (2-24um). The AKARI performed all sky survey in 6 IR bands (9, 18, 65, 90, 140, and 160um) with 3-10 times better sensitivity than IRAS, covering the crucial far-IR wavelengths across the peak of the dust emission. Combined with a better spatial resolution, AKARI can much more precisely measure the total infrared luminosity (L_TIR) of individual galaxies, and thus, the total infrared luminosity density of the local Universe. In the AKARI NEP deep field, we construct restframe 8um, 12um, and total infrared (TIR) luminosity functions (LFs) at 0.15

References:

# Infrared Luminosity Functions of AKARI-SDSS Galaxies Goto, T. et al. 2011, MNRAS, 414, 1903

# Luminosity Functions of Local Infrared Galaxies Revisited: Implications to the Cosmic Star Formation History and AGN Evolution Goto, T. et al. 2011, MNRAS, 410,5 73

# Evolution of Infrared Luminosity functions of Galaxies in the AKARI NEP-Deep field: Revealing the cosmic star formation history hidden by dust Goto, T. et al. 2010, A&A, 514A, 6

# Environmental dependence of 8um luminosity functions of galaxies at z~0.8 Comparison between RXJ1716.4+6708 and the AKARI NEP deep field. Goto, T. , et al., 2010, A&A, 514A,7

Protoplanetary disks, which are formed as by-products of star formation, are the most probable site of planet formation. In fact, more exoplanets have been discovered, urging us toward detailed studies of protoplanetary disks. Because these disks are very compact with a typical size of 100 AU, high angular resolution observations, such as those using mm and submm interferometers are the key to study them in detail. In my talk, I will present recent observations of protoplanetary disks around protostars as well as pre-main-sequence stars.

Markus is an Adaptive Optics Scientist at ESO Garching, ESO Responsible for NACO and the ESO representative for the next-generation VLT extreme AO system SPHERE. He is also the PI of the Extreme AO System EPICS for ESO's Extremely Large Telescope and has done extensive work on high-contrast imaging planet searches and characterization. He will speak about Current and Future High-Contrast Imaging Projects at ESO.

Using a sample of 123 X-ray clusters and groups drawn from the XMM-Cluster Survey first data release, we investigate the interplay between the brightest cluster galaxy (BCG), its black hole, and the intra-cluster/group medium (ICM). It appears that for groups and clusters with a BCG likely to host significant AGN feedback, gas cooling dominates in those with TX > 2 keV while AGN feedback dominates below. This can be understood through the subunity exponent found in the scaling relation we derive between the BCG mass and cluster mass over the halo mass range 1013 < M500 < 1015Msol, such that BCG AGN in groups can have relatively more energetic influence on the ICM. The LX - TX relation for systems with the most massive BCGs, or those with BCGs co-located with the peak of the ICM emission, is steeper than that for those with the least massive and most offset, which instead follows self-similarity. This is evidence that a combination of central gas cooling and powerful, well fuelled AGN causes the departure of the ICM from pure gravitational heating, with the steepened relation crossing self-similarity at TX = 2 keV. Importantly, regardless of their black hole mass, BCGs are more likely to host radio-loud AGN if they are in a massive cluster (TX & 2 keV) and again co-located with an effective fuel supply of dense, cooling gas. This demonstrates that the most massive black holes appear to know more about their host cluster than they do about their host galaxy. The results lead us to propose a physically motivated, empirical definition of 'cluster' and 'group', delineated at 2 keV.

I will present new deep and wide narrow-band surveys undertaken with UKIRT, Subaru and the VLT; a unique combined effort to select large, robust samples of H-alpha (Ha) emitters at z=0.40, 0.84, 1.47 and 2.23 (corresponding to look-back times of 4.2, 7.0, 9.2 and 10.6 Gyrs) in a uniform manner over ~2 sqdeg in the COSMOS and UDS fields. The deep multi-epoch Ha surveys are sensitive to Milky-Way SFRs out to z=2.2 for the first time, while the wide area and the coverage over two independent fields allows to greatly overcome cosmic variance. A total of over ~600 sources per epoch are homogeneously selected. Overall, the evolution seen in Ha is in good agreement with the evolution seen using inhomogeneous compilations of other tracers of star formation, such as FIR and UV, jointly pointing towards the bulk of the evolution in the last 11 Gyrs being driven by a strong luminosity/SFR increase from z~0 to z~2.2. Our uniform analysis allows to derive the Ha star formation history of the Universe, for which a simple time-parametrisation is a good approximation for the last 11Gyrs. Both the shape and normalisation of the Ha star formation history are consistent with the measurements of the stellar mass density growth, confirming that our Ha analysis traces the bulk of the formation of stars in the Universe up to z~2.2. We are also exploring the large, multi-epoch and homogeneously selected samples of Ha emitters to conduct detailed morphology, dust, clustering, environment and mass studies which are providing us with a unique view on the evolution of star-forming galaxies and what has been driving it for the past 11 Gyrs.

Since the star formation rate (SFR) density of galaxies is an order of magnitude higher at high redshift than in the local universe, emission-line galaxies are prominent at earlier cosmic time, and thus are useful probes of the evolution of galaxies. Current techniques to identify the emission-line galaxy population include grism surveys, slit spectroscopy, and narrow-band imaging. I will focus on the properties of emission-line galaxies selected through narrow-band imaging, drawing on two different surveys, the Subaru Deep Field (SDF) and the NewH-alpha Surveys. First, I will discuss results on the dust attenuation of 400 H-alpha selected galaxies at z=0.4 and z=0.5 from the SDF. I will present the highest redshift Balmer decrement measurements for 60 individual galaxies, revealing a correlation of dust attenuation with stellar mass and H-alpha luminosity. I will also show that the dust attenuation corrections derived from modeling the rest-frame 1000 Angstrom to 1.6 microns SEDs, which are correlated with the individual Balmer measurements, are reliable. With reliable constraints, we determine that two-thirds of star formation is obscured at z~0.5. Second, I will then use our unique samples of z~1.5--1.6 [OII] emitting galaxies identified in the SDF to study the stellar population of high-z galaxies selected through narrow-band imaging. The [OII]-selected population spans a diverse population of star-forming galaxies with typical stellar ages of 300 Myrs and stellar masses of 3 X 10^9 Msun. We have also compared our sample against common techniques (i.e., "BX/BM" and BzK) to select high-z galaxies, and find that the narrow-band selection simultaneously spans both populations. This strongly indicates that selection biases present in the narrow-band samples are minimal compared to popular color selections. Finally, I will describe the NewH-alpha Survey, which uses near-infrared narrow-band imaging from NOAO/CTIO's NEWFIRM and Magellan's FourStar to extend the H-alpha luminosity functions (LFs) to z=0.81 and z=2.2. These LFs are the most reliably constrained with (1) significant spectroscopic confirmation for the lower redshift sample, and (2) the use of a second narrow-band filter to detect [OII] emission for >80% of our z=2.2 H-alpha emitters, thus providing a highly confirmed z=2.2 sample. With these LFs, I will discuss constraints on the faint-end slope of the H-alpha LF and the H-alpha SFR densities at these redshifts.

The absorption-selected galaxy sample would have many advantages for the studies of galaxy properties, and therefore the big questions on the galaxy formation mechanism. Recent work on a nearby Lyman Limit System in 3C 232 shows the example and the importance to extend such a study to high-z samples. For this talk, I will firstly report the progress of our research work on this subject, and then briefly introduce the current status of some Chinese Astronomical projects.

I will present our latest results that address the question, whether interactions and subsequent mergers of galaxies are an efficient mechanism by which black holes grow? We specifically use the zCOSMOS spectroscopic redshift survey to generate a large sample of kinematic galaxy pairs up to z~1 and the Chandra X-ray observations of COSMOS to identify those that host AGNs including the obscured population. I will further discuss the importance of mergers relative to other processes capable of supplying gas to the nuclear region thus available for accretion onto a central supermassive black hole.

Heavy element abundance provides a fossil record of galaxy formation and evolution. Metallicity is a crucial parameter to constrain the feedback processes in galaxies such as galactic-scale winds and gas inflows. However, because of the requirement of high S/N spectra, metallicity is a very difficult quantity to obtain at high redshift, especially in the so-called redshift desert of 1 < z < 3. The current best method to obtain metallicity at high redshift is to use strong gravitationally lensed galaxies. In this talk, I will present the first results of our lensing survey into the metallicity properties of star-forming galaxies, based on our MOIRCS/Subaru observations. The powerful magnification of gravitational lensing also allows us to obtain spatially resolved metallicity for a few galaxies at high-z. I will discuss the implications for disk formation scenarios from these spatially resolved galaxies.

It is on galactic scales that our understanding of the cosmological evolution of matter is most incomplete. Many of the predicted features of galaxies, such as faint satellites and diffuse stellar haloes, are extremely low surface brightness, and so the Milky Way, M31 and M33 are some of the only large galaxies in the Universe and that can provide robust tests of many fundamental aspects of galaxy formation models. The Pan-Andromeda Archaeological Survey (PAndAS) is a large, deep, CFHT, photometric survey that has surveyed nearly 400 sq.degrees in the surroundings of the M31/M33 sub-group, and which is providing the deepest and most complete panorama of galaxy haloes available. Here, I will review recent results from PAndAS, including follow-up observations with Subaru and other facilities, and discuss the future development of this field with an eye on the next generation of astronomical facilities.

Today astrophysical research in Kazakhstan is being developed in theoretical and observational aspects. In particular, computational astrophysics and stellar dynamics are gaining more momentum due to international collaboration. Meanwhile one of the main project to raise observational research is to build a new 3.6 meter ground telescope and to participate in the international space project "World Space Observatory - Ultraviolet".

The young (2 Myr) solar analog LkCa 15 is located in the Taurus-Auriga star forming region, and has since 2005 been known to host a massive circumstellar disk, whose mid-IR spectrum indicates the presence of an inner gap. In 2010, HiCIAO at Subaru observed what has been interpreted as a gap in reflected light in the disk, suggesting that a solar system analog is in the making. Last week was announced the discovery of a likely protoplanet orbiting LkCa 15 well inside the gap using non redundant masking interferometry at the Keck Telescope. I will present this discovery, and discuss what it suggests for the instrumentation development we are currently conducting with the SCExAO upgrade of HiCIAO, leading to the following prediction: the direct observation of forming planets in young associations, often presented as one of the major science themes for the second generation instrumentation of an extremely large telescope (ELT) like TMT, will actually be covered before ELTs are built, using modern high angular resolution techniques on a telescope like Subaru.

Cooling of infrared instruments for TMT may require some new methods that have not been typically considered previously for astronomical instrumentation. In particular as next generation AO systems come online, vibration concerns are becoming ever more critical. In this talk I will outline the main options available for cryocooling of instruments describing the advantages and disadvantages of Gifford-McMahon, Joule-Thomson, Stirling and Turbo-Brayton coolers, considering vibration, cost, complexity and reliability. I will describe the work being done to select the best option for TMT and the technical challenges that come with those choices.

The Thirty-Meter Telescope is being designed by an international team of scientists and engineers to provide diffraction-limited images and spectra that will be highly synergistic with the James Webb Space Telescope and other facilities such as ALMA. The design is in an advanced stage, and a wide range of project-activities are underway. It will open up a new and exciting realm of astronomical explorations from our Solar System to the so-called First Light objects that formed soon after the Big Bang. This talk will describe the science and instrumentation of this extremely large telescope.

Lunar occultations (LO), the simplest and cheapest high angular resolution technique, has largely extended its potential science cases thanks to that NIR arrays at 8m class telescopes can now image at a few milliseconds rate.

Since Mar 2006 these kind of observations are being regularly conducted at VLT/ISAAC, achieving a limiting angular resolution of less than 1 mas and a limiting magnitude of K=12.5 mag, which constitutes a unique combination among other techniques.

I will overview the basics behind the LO technique. I will also present the LO runs conducted at the VLT/ISAAC so far and summarize their performance. Some representative results will be shown, in fields such as detection of very close and faint binaries components, direct meaurements of stellar diameters, detection of sources with extended emission (circumstellar shells, YSOs, masers, etc.), and interferometric calibrators database feed, etc.

We present the results of near- to mid-infrared spectroscopic observations of heavily obscured ultra-luminous infrared galaxies (ULIRGs). ULIRGs radiate most of their extremely large, quasar-like luminosities (>10^12 L_sun) as infrared dust emission. Since the energy source of the ULIRGs are thought to be buried within the thick dust and thus not easy to observed from UV to optical, the observations at longer wavelength, i.e., infrared observations play an important role to study them. We have carried out continuous and high-sensitivity infrared spectroscopic observations at 2-13um toward 24 obscured ULIRGs with AKARI/IRC slit-less spectroscopy, which is one of the unique capability of AKARI. The 2-5um spectra are especially valuable, because Spitzer does not have spectroscopic capability in this wavelength region. The spectra show many absorption and emission features from dust, molecules, atoms, and ions. In addition to the many PAH emission features (tracers of starburst activity) and some dust absorption features (tracers of obscured AGNs), we have successfully detected absorption feature due to water ice (indicating the presence of cold molecular gas) and absorption feature caused by gaseous CO (evidence of the existence of warm molecular gas). In order to reveal physical conditions of molecular clouds in ULIRGs directly, we are now making high-resolution spectroscopic observations of fundamental ro-vibration absorption lines of gaseous CO in M-band using the IRCS+AO188 on the Subaru Telescope. This is a unique technique which enable us to determine temperature and column densities of molecular clouds very accurately. We will show these observation results and discuss the physical condition of the molecular clouds in ULIRGs,

Typical spectroscopic surveys aiming at z>1.4 galaxies have been conducted with optical instruments and targeting star-forming galaxies with relatively blue in rest-frame UV. Thus, high redshift passive galaxies are almost fully missed in these surveys because they are very faint in the optical and usually there is no detectable emission line. In this respect, near-IR spectroscopy offers a great advantage for passive galaxies at z>1.4 as strongest spectral features such as 4000A break and Ca H+K absorption lines are redshifted into near-IR, and rest-frame optical continuum is much brighter than that in the rest-frame UV. By taking advantages of such nature of passive galaxies and the capability of multi-object spectroscopy of MOIRCS on Subaru, we have carried out near-IR spectroscopic observation of passively evolving galaxies at z>1.4. We have selected a sample of massive BzK-selected passively evolving galaxies (pBzKs) at z>1.4 from the COSMOS field and observed them with Subaru/MOIRCS. With a exposure time ranging from 7.5 hours to 9.5 hours per object, 18 pBzKs among 34 observed in 3 masks have been identified spectroscopically. I will show the results on their stellar populations based on broad-band SEDs and rest-frame optical spectral features, environments, and velocity dispersion analysis for the brightest object. I will also show average properties of z>1.4 passive galaxies based on a composite spectrum of identified pBzKs.

Chemical abundances in atmospheres of metal-poor stars are well-preserved quantities from the early Universe, which is one of the only observational signatures on the ancient stellar and supernovae nucleosynthesis in the Milky Way Galaxy. Together with phase-space coordinates (position, distance and 3-d velocity components), chemical abundances in old stars have provided tremendous implications on the chemodynamical evolution of the early stage of our Galaxy. In this talk, I will summarize how chemical compositions of nearby stars have been used to make constraints on the formation of each structural component of our Galaxy, namely, the thin disk, thick disk and stellar halo. Then, I will talk about the state of our ongoing Subaru HDS study on homogenous chemical abundance analyses of nearby halo stars. Our sample includes ~90 metal-poor (-4<[Fe/H]<-0.5) dwarf and giant stars located within a few kilo-persec from the Sun, that show a wide range in orbital characteristics (e.g. large eccentricity or highly retro-grade motion). In particular, the sample stars whose orbit reaches the outer part of the Galactic halo are quite suitable for examining the merging history of our Galaxy, since remnants of tidally disrupted stellar systems (e.g. dwarf galaxy), may largely persist in the outer halo. Chemical abundances of key-elements, including alpha, iron-peak and neutron-capture elements have been obtained with a LTE abundance analysis code. We show that the estimated alpha-elements-to-iron abundance ratios ([alpha/Fe]), one of the important diagnostic for star formation history in a stellar system, show a mild decreasing gradient with metallicity. This result is broadly consistent with a hypothesis that the halo stars are partly originated from a system with a lower star formation rate where delayed enrichments of Fe from Type Ia SNe are responsible for the decrease in the [alpha/Fe]. Implications on the building blocks of the Milky Way stellar halo will be discussed based on the estimated abundances of various key-elements will be presented.

Star formation is one of the most important physical processes in terms of galaxy formation and evolution. While there have been tremendous theoretical progress regarding formation of stars and galaxies to provide information on how star formation drive galaxy evolution along the Hubble time, it still remains a big puzzle how galaxies gather gas and turn it into stars and what physical properties regulate the process. In fact, the Kennicutt-Schmidt law was the rule of thumb until various surveys such as THINGS enable us to study star forming galaxies in kpc scale very recently. Studies based on these surveys including Bigiel et al. (2008) based on THINGS survey show that there is a strong correlation between star formation surface density and the sum of neutral and molecular gas surface density while starburst galaxies do not follow the correlation with much higher star formation efficiencies. Yet, it is not only energetic starburst galaxies which deviate from the trend. Galaxies at the low end of gas surface density also form stars with much lower star formation efficiencies even at lower gas surface density than apparent star formation threshold. Combined with their possible low metallicities, these galaxies are testbeds for star formation law and, furthermore, can provide crucial informations on star formation within primordial galaxies in the early Universe. These galaxies also show that there is a systematic trend between H-alpha/UV ratio and optical or/and NIR surface brightness, which suggests non-universal stellar initial mass functions. I will present recent progresses regarding this puzzling low surface brightness regime.

Atlas3D is a new survey combining optical integral-field spectroscopy and multi-band imaging with radio and millimeter interferometry for a complete, volume-limited sample of 260 early-type galaxies observed within the local 40 Mpc volume - the largest survey of its kind. This K-band selected sample spans a range in mass from 10e10 to 10e12 solar masses, and probes two orders of magnitude in local galaxy density, giving a significantly larger range in mass and environment than previous similar works. I will present an overview of the project and recent results, then focus on the stellar populations of the sample and trends with other global properties uniquely accessible to our survey.

In Hawaiian,`IMAKA means scenic point or beautiful view, and indeed Mauna Kea offers a truly unique view into the heavens. The structure of the turbulence of the atmosphere above Mauna Kea may offer yet another window in parameter space to observe the Universe. By including what we know about the atmosphere into our instrument design, we think we can deliver images with a resolution of 0.3" over a 0.8 degree diameter field on the 3.6m CFHT. To achieve such an ambitious goal, we have developed a specific strategy to address the various sources of image degradation. First, we are aware that much of the turbulence is generated within or by our dome. A now independent project has been started at CFHT on dome venting and thermal dissipation mitigation. The next source of turbulence is in the ground or boundary layer. Recent studies have shown that this is very confined in a layer close to the ground (<70m). There is a relationship between the thickness of the turbulence, the size of the corrected field and the order of the correction of a GLAO system and we find that that the measured thickness of the boundary layer would allow for degree size fields to be corrected. Finally, the next major source of image degradation of the dome and GLAO corrected image is the tip-tilt of the free atmosphere. An orthogonal Transfer CCD can shuffle charges across pixels in real time during an exposure and is therefore capable of locally correcting for tip-tilt across sub-arrays. Depending on the density of tip-tilt stars and the trade-off between image quality and homogeneity, simulations have shown it will be possible to achieve a median image quality of 0.3" at 700nm over the required 0.8 degree diameter field. There are many challenges in the `Imaka project, most of them are related to the need to re-image a clean pupil image on a deformable mirror while carrying such a large field: the Lagrange Invariant is as large as MOAO systems on ELTs. But there are also other very interesting issues to be solved in the case of `Imaka. In this talk, I will describe our challenges and opportunities afforded by this original concept.

As the redshift range z=2-4 represents a key epoch in the buildup and evolution of galaxies, studies of the properties of galaxies at these redshifts provide important clues on the physical processes at work during galaxy formation and evolution. I will present results on the evolution of the stellar mass function of galaxies at 1.5< z <4 from the MUSYC, FIREWORKS, and FIRES surveys, putting particular stress on its uncertainties, especially the systematics. I will then present the most recent results from the NEWFIRM Medium-Band Survey (NMBS), focusing on the properties of the most massive galaxies at 3< z <4, on the unexpected results the NMBS data quality and wavelength coverage have returned, and on their implications for our understanding of galaxy evolution. Finally, I will conclude with an overview of ongoing projects aiming to further improve our knowledge on the high-redshift universe.

We characterize the nature of low-luminosity AGNs with star formation rates of the host galaxies, black hole masses, and accretion rates. We develop a new method to identify AGNs using a single (or perhaps two) emission line. With this method, we can cleanly subtract emission line fluxes from star forming regions to extract pure AGN emission, which is crucial to characterize AGN activities. Our tentative results show that accretion rates increase with increasing star formation rates. This suggests that the amount of gas in galaxies may be an important parameter to characterize AGN activities, and it might provide a link between the down-sizing in galaxy star formation and the down-sizing in AGN activities.

Half of the most massive galaxies at z~2 have recently been shown to have surprising and quite extreme properties. With masses like local ellipticals, but sizes like local dwarf galaxies, they have extremely compact stellar populations, orders of magnitudes higher that in any local galaxies. They apparently have disk like structure, old ages (1 Gyr) and quiescent stellar populations already at this high redshift. I review the observational evidence for their extreme properties, and our efforts to learn more about them and put them into cosmological context.

I would like to introduce WISH, the Wide-field Imaging Surveyor for High-redshift. It is a space science mission whose primary goal is to reveal the first-generation galaxies in the early universe. We will launch a 1.5m-aperture telescope equipped with very wide-field (~800 square arcminutes, comparable to the current Subaru prime-focus camera) near-infrared camera, which covers 1 to 5 microns. The ultra-deep survey of WISH will reach 28 AB magnitude, which cannot be achieved by any ground-base telescopes, and plans to cover 100 square degrees of the extragalactic sky. This WISH UDS should detect enormous amount of galaxies in the dawn of the universe, and such galaxies are sufficiently bright to be followed-up spectroscopically with the extremely large telescopes such as TMT. In this sense, WISH is quite complimentary to JWST, and the WISH and TMT are an ideal combination to understand how the first generation of galaxies are formed. Also, the depth, survey area and wavelength coverage of WISH should be quite valuable to other astronomical and cosmological research fields, such as dark energy, evolution of galaxies and AGNs, mapping our Galaxy and the solar system. In this talk, I will summarize the technological development made for WISH so far, and characterize its uniqueness compared to other space-telescope projects under consideration, such as Euclid and WFIRST.

A starburst in the central region of Active Galactic Nucleus (AGN) is thought to be a controller of AGN activity. However, we do not have any common understanding of how the nuclear starburst actually controls the AGN activity yet. There are some models, and these different models predict different relationships between nuclear starburst and AGN. Therefore, measuring the nuclear starburst activities quantitatively and comparing them with AGN activities over a wide range in AGN luminosity can put constraints on the models. In this talk, I will describe our results from the near-IR, K- and L-bands spectra of Seyfert galaxies taken with IRTF/SpeX. We find a positive relationship between the two activities. We also find a significant difference in K-L colors between type 1 and 2 Seyfert galaxies. Our results imply that the AGN activity is triggered by a turbulence induced by the nuclear starburst which is occurring in the outer part of dusty torus.