Subaru Seminars

Quasars are extremely luminous objects, whose enormous radiative energy is powered by supermassive black holes (SMBHs). The mass of SMBHs sometimes reaches up to 10^10 M_sun, but its formation and evolution are still unclear. Thanks to SDSS and recent NIR wide surveys such as UKIDSS and VIKING, our discoveries of quasars reach at z~7. Interestingly, the discovered quasars at z>6 look to be already "matured"; their SMBH mass exceeds 10^9 M_sun, and the inferred metallicity is already higher than the solar metallicity. Deeper quasar surveys are definitely needed to assess quasars in their growing-up phase and to tackle the physics of the SMBH evolution. We are now promoting a new quasar survey using Hyper Suprime Cam (HSC) with numerous AGN researchers in Japan, Princeton, and Taiwan, under the Subaru Strategic Program (SSP) consortium. We have already found photometric candidates of less-luminous quasars (than SDSS quasars) at z~6-7. The combination of the HSC-SSP data and the WISE all-sky survey data brought us a unique sample of heavily obscured AGNs at z~2 (Toba et al., to be submitted soon). For theoretical interpretations of the HSC-SSP outcomes, we are preparing a new quasar mock catalog based on the AGN semi-analytic model (Enoki et al. 2014) and on N-body simulations with a huge volume. In this seminar, I would like to review some recent results of our HSC-SSP quasar survey and show our future prospects, including possible new collaborative works with various newcomers.

Blueshifted absorption lines in the spectra suggest the existence of the outflows in active galactic nuclei (AGNs). Using two-dimensional radiation hydrodynamic simulations, we investigate the origin of the outflows. We found that the radiation force due to the spectral lines generates strong winds (line-driven disk winds) that are launched from the inner region of accretion disks (~ 30 Schwarzschild radii). In a wide range of black hole masses and Eddington ratios, funnel-shaped disk winds appear, in which dense matter is accelerated outward with an opening angle of ~70-80 degrees and with 10% of the light speed. We find that the line-driven winds reproduce the velocity, the column density, and the ionization state of Ultra Fast Outflows (UFOs), which is one of typical outflows in AGNs.

Shock breakout is the bolometrically brightest phenomenon in supernovae. Although it is theoretically proposed in 1970s and is suggested to be a probe of the high-redshift universe, its observation is difficult due to the short duration and X-ray/ultraviolet-peaked spectra. We had constructed theoretical models of shock breakouts in 2009 and 2011 and demonstrated that the shock breakout can be efficiently detected in optical band with Hyper Suprime-Cam. Thus, we have started the shock breakout survey with Hyper Suprime-Cam from Jul 1-2, 2014. In this talk, I will introduce our survey strategy, transient finding system, and initial results.

I will present the results of the completed direct imaging campaign for stars with radial velocity drifts in the HARPS and CORALIE planet-search surveys. Using the radial velocity data which spans over more than a decade, we selected promising targets for direct imaging of sub-stellar companions to solar-type stars. The direct imaging observations were carried out on VLT/NaCo using the angular differential imaging technique. By combining the constraints from direct imaging and radial velocity we derived the frequency of brown dwarfs around sound like stars in the 5 to 50 AU range.

We have discovered 12 galaxies at z ~ 1.2 in SXDS field showing a largely extended (> 30 kpc) [OII] nebula, which we call [OII] blobs (OIIBs). Some of these galaxies are probably experiencing the final phase of star formation with their gas heated and expelled out by AGN/supernova feedback, and quenching star formation whose process is a key to produce passively-evolving ellipticals. One of 12 OIIBs is a giant OIIB with a spatial extent over 75 kpc, which hosts an obscured type-2 AGN. The ongoing outflow process in this object is confirmed by VLT/VIMOS optical spectroscopy with an outflow velocity of 500 - 600 km/s, suggesting that a major heating source of this giant blob is AGN or associated shock excitation rather than supernova feedback. Other OIIBs do not show clear AGN activity, but our spectroscopy confirms a moderate outflow with a velocity of ~ 200 - 300 km/s, suggesting that the outflow of these OIIBs is driven by star formation. The number density of OIIBs with AGN is 5x10^-6 Mpc^-3, comparable with that of AGN driving outflow at the similar redshift. Meanwhile, the number density of all OIIBs including no AGN hosting galaxies is 6x10^-5 Mpc^-3, indicating that 3% of star-forming galaxies at z ~ 1 are quenching star formation through outflows involving spatially extended [OII] emission.

Submm galaxies (SMGs) are key for understanding the dusty-side of star-formation activities at high redshift. SMGs are probably major sources contributing to the extra-galactic background light (EBL) in the submm band, but the EBL is not fully resolved, due to the low sensitivity and limited spatial resolution of the previous submm observations. We thus explore the faint SMGs with the 27 pointing deep ALMA data, which is the largest data to date, at Band 6 that allow us to reliably investigate faint SMGs with the FIR star-formation rate of ~10-100 M_sun/yr, which is comparable to those of optically-selected galaxies, such as BzK galaxies. Exploring the high sensitivity and spatial resolution of ALMA, we have identified 22 faint SMGs that are about 2 times larger than the previous ALMA studies. Combining the bright SMG data in the literature, we derive the number counts at 1.2mm in the wide range of flux densities, 0.1-10.0 mJy. Based on the reliable number counts of the SMGs, we discuss the SMGs' contribution to the EBL, their redshift distribution, and the cosmic dust abundance locked up in SMGs at high redshift.

In this talk, I will give an overview for how the condensed stellar cluster form in the hierarchically collapsing molecular hub-filament system, from the observational aspect. I will first demonstrate the hub-filament cloud morphology from several spatially well resolved low-mass, intermediate-mass, and high-mass cluster-forming regions. I will then elaborate the cloud kinematics and the star forming activities in three OB cluster forming regions W49N, G10.624-0.38, and G33.92+0.11, based on our SMA mosaic and ALMA cycle-1 12m+ACA observations. These results provide the implication for how the super star cluster and the globular star may form.

The William Herschel Telescope (WHT), located at the Roque de Los Muchachos Observatory (La Palma), is a 4.2-m telescope equipped with a variety of instruments for optical and near infra-red observations. Since WHT first light, in the end of the '80, the global astronomical landscape has evolved. On one hand plans are underway for the construction of the next generation of giant telescopes. On the other hand, astronomical studies have been developing in the 'survey mode', which opens a complete new chapter in the way of studying the universe. Therefore, it is time to re-evaluate the part and new work spaces of the existing observational facilities in this scenario. Middle size telescopes, can play important role as they can deliver efficient capability for wide-field astronomy from which survey projects greatly benefits. Indeed, large-scale surveys with wide-field highly-multiplexed spectrographs are necessary to complement and exploit ground-based imaging surveys such as LSST, Pan-Starrs, SDSS, UKIRT and VISTA, radio surveys such as APERTIF, ASKAP, LOFAR, MeerKAT and SKA, and space-based surveys such as Gaia, EUCLID, eROSITA, and WFIRST. The WHT is getting ready to contribute to this by the end of 2017 with WEAVE: a wide-field (2-degrees), multi-object spectrograph fed with 1000 fibres. WEAVE will deliver spectra at R~5,000 in the range of 370 nm to 1000 nm and higher resolution spectra of R~20,000 over smaller wavelength ranges. It will be also equipped with a series of mini-IFUs and a monolithic large-IFU. In this talk I will speak about WEAVE at theWHT and the promising future ahead.

I present a class of newly discovered distant dust-enshrouded galaxies with extremely high luminosity, including several Extremely Luminous Infrared Galaxies that reach 10^14 L_Sun. Selected by the extreme red color in WISE bands, their SEDs incorporating the WISE, Spitzer, and Herschel PACS and SPIRE photometry indicate the hot dust dominates the bolometric luminosity. These galaxies are likely powered by highly obscured active galactic nuclei (AGN), and there is no evidence suggesting these systems are beamed or lensed. If these AGNs are radiating at the Eddington limit, the existence of ELIRG at z > 3 places strong constraints on the supermassive black hole (SMBH) growth history since the SMBH seeds form at z ~< 20, suggesting that these supermassive black holes may be born with large mass, or have a very rapid mass assembly, presumably by chaotic accretion. The multi-wavelength follow-up results on selected cases suggest that they are different from normal populations in local M-sigma relation and FIR-radio correlation. Their low source density (~ 10^-5 of LIRGs' at similar redshift) implies that these objects are intrinsically rare, or these objects are a short-lived phase in a more numerous population. If later is the case, these hot, dust-enshrouded galaxies may be an early stage in the interplay between AGN and galaxies.

2012 DA14 is a near-Earth object in diameter of several ten meters, which passed closely to the Earth at a distance of about 27,700 km inside a geosynchronous orbit on February 15, 2013 UT. Around the closest approach, the asteroid lightened brighter than 7th magnitude in the optical and had a wide variation of solar phase angle. This event was a great opportunity to investigate the surface properties of small-sized asteroids, such as geometric albedo and regolith structure. We performed a time-series photometric observation for 2 hours around the closest approach of 2012 DA14 using the 0.55-m telescope at Saitama University. Although this observation was very difficult due to the extremely fast sky motion (50 arcmin/min in maximum!), we successfully acquired good photometric data all over the observation. We also performed an additional observation on the next night and determined the rotation period and lightcurve amplitude. Our data analysis shows that the phase curve is significantly shallower than that of L-type asteroids which 2012 DA14 has been classified as. 2012 DA14 is likely to be coated with a coarse surface that lacks fine regolith particles and/or a high albedo surface.

High redshift star-forming galaxies in the epoch of cosmic reionization (EoR) have been usually detected via either their Lyman alpha emission or UV continua. However, UV lights from such galaxies trace only the lights from ionized gas or stars, and we have seen merely a portion of star formation activities in galaxies. Another aspect yet unexplored is dust-obscured star formation in EoR galaxies, and rest frame far-infrared (FIR) molecular/atomic lines and continuum can probe it because they reflect fuel for star formation and UV light from stars once absorbed and re-emitted by dust, respectively. FIR lights from galaxies in EoR are redshifted to mm wavelengths and observable from the ground with ALMA. Among many FIR lines, 158 micron [CII] is the strongest cooling line of an interstellar medium and suited for probing faint distant galaxies such as ones in EoR. Here I report the first ALMA observation of [CII] line and underlying FIR (redshifted 1.3 mm) continuum of a normally star-forming galaxy in EoR, a z=6.96 Lyman alpha emitter, IOK-1. Probing to unprecedentedly deep limits, I found it undetected in both [CII] and FIR continuum. I will present the constraints on FIR spectral energy distribution of IOK-1, its dust mass, total FIR/IR luminosity, dust-obscured star formation rate and [CII] luminosity and discuss their implications for early galaxy formation in the context of gas and dust.

We report our Keck/MOSFIRE and Magellan/LDSS3 spectroscopy for an [OII] Blob, OIIB 10, that is a high-z galaxy with spatially extended [OII] 3726,3729 emission over 30 kpc recently identified by a Subaru large-area narrowband survey. The systemic redshift of OIIB 10 is z = 1.18 securely determined with [OIII] 4959,5007 and Hbeta emission lines. We identify FeII2587 and MgII 2796,2804 absorption lines blueshifted from the systemic redshift by 80 +/- 50 and 260 +/- 40 km/s, respectively, which indicate gas outflow from OIIB 10 with the velocity of 80-260 km/s. This outflow velocity is comparable with the escape velocity, 250+/- 140 km/s, estimated under the assumption of a singular isothermal halo potential profile. Some fraction of the outflowing gas could escape from the halo of OIIB 10, suppressing OIIB 10's star-formation activity. The major energy source of the outflow is unclear with the available data. Although no signature of AGN is found in the X-ray data, OIIB 10 falls in the AGN/star-forming composite region in the line diagnostic diagrams. It is possible that the outflow is powered by star formation and a type-2 AGN with narrow FWHM emission line widths of 70-130 km/s.

We will present statistical properties of passively-evolving and post-star burst galaxies at z = 1.5 - 2.0 in the COSMOS field. Using simple color sele ction criteria with the ultra-deep Suprime-Cam z'-band and the UltraVISTA DR 2 data, we selected passive and post-starburst galaxies at the redshift. We investigated the stellar mass function of these passive and post-starburst g alaxies separately, and found that the low-mass end slopes are significantly different between these two populations. At low mass of the stellar mass fu nction of these passive galaxies, the number density of these passive galaxi es decreases with decreasing stellar mass at low-mass end, and the number de nsity of low-mass passive galaxies is smaller than massive ones. On the othe r hand, that of the post-starburst galaxies is almost constant at low mass, and the low-mass end slope is significantly flatter than passive galaxies. S ince post-starburst galaxies evolve into passive galaxies within ~1Gyr, thes e galaxies are expected to cause stronger evolution of the number density of the passive population at lower mass.

VIRUS-W is a fiber based optical IFU spectrograph that we constructed specifically to study the dynamical properties of kinematically cold stellar systems such as disks and dwarf galaxies. The instrument is a spin-off of the main survey instrument for the Hobby-Eberly Dark Energy Experiment (HETDEX). I will introduce the instrument itself and also talk about its heritage. Its high spectral resolution positions VIRUS-W uniquely to detect low level rotations of stellar systems and to study the actual fine structure of line-of-sight velocity distributions. I will discuss a few recent science results such as the genuine kinematic decomposition of the spiral galaxy NGC7217 and the detection of ubiquitous central rotation of Milky Way globular clusters.

Spectroscopic surveys of quasars yield a random sample of intervening absorbing gas clouds that can be used to constrain the on-going and summative enrichment processes in the universe. The CIV and MgII doublets have proven to be important tracers of the circum-galactic medium and its evolution from z = 6 to 0. We vastly improved the 1.5 < z < 4.5 absorber measurements by identifying over 15,000 CIV systems from a survey of thousands of SDSS DR7 QSOs. MgII absorption systems have been well-studied at 0.4 < z < 2.3, in SDSS quasar spectra, since the early data-release, and we surveyed the SDSS DR7 quasar catalog for MgII absorbers, as part of our on-going effort to compile fairly comparable samples of metal lines. I will summarize the SDSS CIV and MgII absorbers, relate them to galaxies and galaxy evolution, and discuss what's next.

Over 400 small (a few 10") rings, disks and shells have been discovered from visual inspection of the Spitzer /MIPSGAL 24 um mosaic images. These MIPSGAL bubbles (MBs) are pervasive through the entire Galactic plane in the mid-infrared. They span a large range of morphologies, sizes and fluxes. The analysis of near- to far-IR broadband images has unveiled that 54 MBs (about 13%) have central sources at 24 um while this number rises to at least 100 in the IRAC or 2MASS images. The extended emission is detected in about two thirds of the MBs at 70um but less than one third at any other IR wavelengths. When we published the catalog, only 15% of the MBs were identified or associated with stars of known spectral types. Most of the known MBs were associated with planetary nebulae while a few were supernova remnants, Wolf-Rayet stars (WR), luminous blue variables (LBV) and other emission line stars. The MBs are thus suspected to be associated with stars in their late stages of evolution, with at least a fraction of them being massive. In this talk, I will address the two main questions arising from this discovery: (1) what are the MBs? and (2) what is the origin of their emission? I will first present the catalog of the MBs and their general properties, in terms of morphologies, sizes, and broadband fluxes. In particular, I will show that mid to far-IR observations from the Spitzer and Herschel Galactic plane surveys provide a direct measurement of the dust mass ejected by the MBs. Then, I will detail some of the many follow-up observations we obtained to identify the origin of the mid-IR emission and the nature of the unknown objects. I will focus on: (1) unique Spitzer/IRS observations of 14 MBs that lead to the discovery of several highly excited, dust poor planetary nebulae, and several dust rich, massive star candidates; and (2) Palomar and VLT near-IR observations of central sources in MB, that reveal a large number of new massive stars. I will discuss other paths we are exploring, from radio to optical. I will summarize the results of these investigations and discuss their relevance for the complete catalog.

Galaxies and massive black holes (BHs) are presumed to grow via galactic merging events and subsequent BH coalescence. As a case study, we investigate the merging event between the Andromeda galaxy (M31) and a satellite galaxy (Miki et al. 2014). We compute the expected observational appearance of the massive BH and stars around it that were at the center of the satellite galaxy prior to the merger, and are currently wandering in the M31 halo (Kawaguchi et al. 2014). We demonstrate that a radiatively inefficient accretion flow with a bolometric luminosity of a few tens of solar luminosities develops when Hoyle-Lyttleton accretion onto the BH is assumed. We compute the associated broadband spectrum and show that the radio band (observable with JVLA, ALMA and SKA) is the best frequency range to detect the emission. We also evaluate the mass and the luminosity of the stars bound by the wandering BH and find that such a star cluster is sufficiently luminous that it could correspond to one of the star clusters found by the PAndAS survey. The discovery of a relic massive BH wandering in a galactic halo will provide a direct means to investigate in detail the coevolution of galaxies and BHs. It also means a new population of BHs (off-center massive BHs), and offers targets for clean BH imaging that avoids strong interstellar scattering in the center of galaxies.

Correlation between stellar parameters and planet properties, including planet occurrence rates, can be considered as fundamental information for planet formation and evolution in various environment of planet birthplace. Thanks to increasing the number of planet samples, statistical studies become available. In particular, hundreds of Jovian-planet samples have been contributing to constrain planet formation theories taking account of evolutions of protoplanetary disks and planet orbits such as orbital migration and planet-planet scattering. However, observational and statistical study for planet distribution is still open to debate, particularly in its correlation with their host stellar metallicities. While previous studies of planet-metallicity correlation have mainly focused on integrated occurrence rate of planets over planetary mass and orbital period, it is also important to reveal dependence of mass and period distribution of planets on stellar metallicity for a deeper understanding of orbital evolution. Recent studies of circumstellar disks have suggested that stellar metallicity may have significant importance to the disk-lifetime, a key parameter of planetary migration theory. Since 2009, we have conducted a radial-velocity survey for metal-rich solar-type stars mainly using the 188-cm telescope at Okayama Astrophysical Observatory and the Subaru Telescope. This planet-search program originates from the N2K program that mainly aimed for detecting Hot-Jupiters around metal-rich solar-type stars. To date, we have discovered 5 new exoplanets around three metal-rich stars. The planet masses range between 1 MJ and 6.5MJ in the period range of 280-2300 days. In this talk, I will review the backgrounds and discuss the features of these detected planets.

Direct imaging is the new frontier in exoplanet detection and the means by which we will eventually discover a true Earth twin around a Sun-like star. In this talk, I introduce the new observing techniques and powerful image processing methods used to directly image planets and present recent/unpublished results clarifying the strange atmospheric properties of imaged, super-jovian planetary companions around HR 8799 and ROXs 42B. The next 5-10 years will see an explosion of new discoveries in this field due to the commissioning of ground-based extreme adaptive optics imagers capable of revealing many young jovian planets at Jupiter/Saturn-like separations, including the Subaru SCExAO project. I will close by describing exoplanet imaging science with the TMT, how TMT's instrumentation may (nearly) image a rocky planet in the habitable zone around nearby stars, and how SCExAO serves as a crucial bridge towards this future.

The formation and evolution of supermassive black holes (SMBHs) and their host galaxies are tightly connected based on various correlations between the mass of SMBHs and the mass, or velocity dispersion of host galaxy's bulge. Although they are believed to coevolve through various physical processes, such as gas accretion and mergers, the details of these processes are still under hard scrutiny: what governs BH formation and growth, what regulates host galaxy growth, and if their growths have different phases with respect to each other. Regarding the link between the growth of BHs via active galactic nucleus (AGN) activity and the growth of host galaxies through star formation (SF) activity, probing the direct connection between them has been extremely tricky due to their hugely different size scales and the domination of the UV emission and hydrogen recombination lines from UV flux. Utilizing slit-less spectroscopic capability of AKARI space telescope, several mission projects were carried out to measure the 3.3 micron polycyclic aromatic hydrocarbon (PAH) emission feature as a star formation rate proxy and to investigate if the 3.3 micron PAH can be a reliable SFR proxy and how AGN and SF activities of a wide range of AGNs are inter-connected. I will present the results showing the symbiotic nature of these two activities based on several AKARI projects including Quasar Spectroscopic Observation with NIR Grism (QSONG).

I will present the results from the deepest and widest narrow-band surveys ever undertaken with the best 4-8 m telescopes (CFHT, UKIRT, Subaru and the VLT); a unique combined effort to select large, robust samples of (mostly) H-alpha (Ha) star-forming galaxies at z=0.20, 0.40, 0.8, 0.84, 1.47 and 2.23 (corresponding to look-back times of 2, 4.2, 7.0, 9.2 and 10.6 Gyrs) in a uniform manner over ~2-10 deg^2 in the COSMOS, UDS and SA22 fields. Our results reveal the exponential decline of the typical star-formation rate of galaxies (SFR*) over the last 11 billion years, and very little evolution in the stellar mass function of star-forming galaxies, with strong implications to the main drivers of galaxy evolution. Our Ha star formation history also implies a stellar mass density growth which is in perfect agreement with independent observations of the stellar mass density growth over the last 11 billion years, finally resolving the worrying disagreement seen in the literature. Finally, I will show how our large and homogeneously selected samples of Ha emitters across cosmic time are also being used to measure and understand the evolution of star-forming galaxies in the last 11 Gyrs, by conducting detailed resolved dynamics (e.g. SINFONI, KMOS), dust (e.g. ALMA, Herschel, Spitzer), clustering, environment, and (resolved) metallicity studies (e.g. KMOS, FMOS).

I will present the first results from the CF-HiZELS survey, which is a large area, medium depth (22.2 AB) near infrared narrow-band survey covering 10 square degrees in part of the SSA22 field with the Canada-France-Hawaii Telescope. I will present how we used these observations to obtain the largest samples of high redshift emission line galaxies to date, such as ~3500 star-forming H-alpha emitters at z=0.8 and ~900 [OII] emitters at z=2.2. These samples are now being used for unique studies of resolved dynamics and metallicities with new instruments as KMOS. The main focus is on how we searched for Lyman alpha candidates at z=8.8 by applying a set of stringent criteria on our sample of line-emitters. I will show how to distinguish z=8.8 galaxy candidates from lower redshift interlopers, how including line-emission improves photometric redshift constraints and I will present the most plausible Lya at z=8.8 candidates to date and the spectroscopic follow-up with the SINFONI instrument on the VLT. I will shortly discuss the results, which have strong implications for existing samples of very high redshift LAE candidates and for ongoing and future surveys. I will conclude with our future plans on how we will improve the understanding of the Lya emission line at high redshift using a wide variety of surveys.

I explain a principle (proposal) to measure directly the black hole parameters (mass and spin angular momentum), which makes use of the time series data obtained by one telescope. There are two points in our proposal: (1) Consider the case that an emission of light with short duration (burst-like emission) occurs near a black hole. Then, due to the strong gravity of black hole (strong gravitational lensing effect), some light rays wind (or coil) around the black hole before coming to observer. (And some light rays are absorbed by the black hole.) This means that, before coming to the observer, one light ray propagates along the shortest path which does not wind around the black hole ("0th ray" or "direct ray"), and another light ray propagates along the secondary short path which winds once around the black hole ("1st ray" or "secondary ray"). (2) When the observer detects the 0th and 1st rays by one telescope, he/she can (in principle) readout two informations from the time series data obtained by the telescope: the delay between detection time of 0th and 1st rays, and the ratio of intensity (or amplitude) of 0th and 1st rays. By the general theory of relativity, these two quantities (time delay and intensity ratio) are determined by the black hole's mass and spin angular momentum. In this talk, I propose a method how to readout those two quantities from the time series data, and explain (without stepping in mathematics of general relativity) how to readout the black hole parameters from those two quantities.

Weak gravitational lensing is a powerful tool for understanding how galaxies populate dark matter halos. We use the publicly-available CFHTLenS galaxy catalog with shapes and photometric redshift information in order to measure the weak lensing signal of (CMASS) galaxies in the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey. By combining with the measurement of the projected auto-correlation function of CMASS galaxies over the entire BOSS DR11 area, we fit a halo model to the measurements assuming a Lambda-CDM cosmological model. I will present astrophysical constraints on the halo occupation distribution of CMASS galaxies, the structure of their dark matter halos, and the amount of stellar mass within these galaxies obtained from our analysis. Finally, I will also present cosmological constraints on the matter density parameter and amplitude of fluctuations using this new data. I will contrast these and our previous SDSS-I results with those obtained from the cosmic microwave background experiment Planck and discuss the complementarity between these results. I will conclude by highlighting the future prospects of such analyses with the Hyper Suprime-cam survey.

In this talk the speaker, SR Kulkarni, first surveys the landscape of optical instruments on large telescopes. As a case study he uses the published output of the Keck Observatory and analyzes the impact and productivity of the different instruments. In the second part of the talk the speaker looks at the cost growth of optical instruments and makes some predictions of optical astronomical instrumentation.

I will discuss some of the observational capabilities that the Thirty Meter Telescope will provide and some of the areas of study that will benefit from the TMT's capabilities. I'll describe how the telescope design was developed to support a broad range of observing capabilities, how the observatory is being engineered and the plans for operations. Finally I'll describe the avenues through which astronomers can actively participate in the project.

High resolution very long baseline interferometry (VLBI) images of nearby massive black holes have the power to address fundamental questions about the physics of black holes. This includes the most accurate constraints on the mass density of the black hole, detection of the black hole spin, and exploration of extensions to general relativity (GR). In particular, Event Horizon Telescope (EHT) observations will probe Sgr A* and M87, the two sources with the largest angular diameter black holes on the sky, over the coming years with increasing sensitivity and accuracy in imaging. Unfortunately, we do not fully understand the physical processes that are driving accretion and outflow in these sources. To address the fundamental black hole physics questions, we need to develop a deeper knowledge of the astrophysics of these sources. The periastron passage of the G2 gas cloud with Sgr A* at ~1000 Schwarzschild in Spring of 2014 gives us an unprecedented opportunity to study a wide range of astrophysical models for accretion and outflow. I describe here observations from millimeter to X-ray wavelengths that enable us to create the necessary context for understanding physics at a few Schwarzschild radii. These include centimeter wavelength VLBI, millimeter polarimetry, and light curve analysis. The serendipitous discovery of the Galactic Center magnetar, SGR 1745-29, has provided a powerful new probe of the Galactic Center environment, including the gas density, magnetic field strength, and nature of the interstellar scattering screen. The discovery also raises important questions about the detectability of pulsars in close orbit to Sgr A* and the pulsar population in the Galactic Center overall.

Nearby dwarf galaxies provide us a unique opportunity to investigate galaxy formation and evolution through their resolved stars. Thanks to systematic surveys in the SDSS data archive, the number of Galactic dwarf satellites (dSph) is doubled in recent years. The newly discovered ultra faint dwarf (UFD) galaxies are roughly 10 to 100 times fainter than the well-known "classical" dSphs and even fainter than globular clusters, having amorphous morphology and too low surface brightness to be found by the photographic plate. Their star formation histories and detailed structural properties provide a clue to understanding of the galaxy formation at the faint-end and of the Galactic tidal effects for the satellite galaxies. I will present the deep colour-magnitude diagrams (CMDs) of faint Galactic dSphs, including UFD galaxies. The resulting CMDs show that the brighter galaxies have relatively younger populations than these of fainter ones. In the brighter dSphs, the younger populations are more spatially concentrated to the galaxy center than old stars, indicating that the star formation in the central region continued at least a few Gyr. On the other hands, the CMDs of the faintest satellites show a single epoch of star formation as metal-poor Galactic globular clusters, and it is very different from those of massive star clusters that have multiple stellar generations. These results indicate that the gaseous matter in the progenitors of UFDs were removed more effectively than those of brighter dSphs at an occurrence of the initial star formation, and also the star formations in UFDs were regulated by different mechanisms from those of massive star clusters. I will also introduce an up-coming opportunity for studying Galactic Archeology by Hyper Suprime-Cam SSP survey.

I will present observational results on the large-scale connection between the intergalactic medium (IGM) and galaxies at z<1. I will focus on a statistical approach to this problem by measuring the gas-galaxy 2-point cross-correlation, and comparing it with both the galaxy-galaxy and the gas-gas auto-correlations, as a function of different absorber/galaxy properties. These results come from one of the largest samples of HI absorption lines and galaxies in the same volume obtained from deep spectroscopic galaxy surveys (VLT/VIMOS, Gemini/GMOS, Keck/DEIMOS) around QSOs having high resolution UV spectroscopy (HST/COS, HST/FOS). I will also present results from a complementary study on HI absorption systems found within and around galaxy voids at z<0.1.

The chemical enrichment of galaxies, driven by star formation and regulated by gas outflows from supernovae and inflows from cosmic accretion, is a key process in galaxy formation that remains to be fully understood. The greatest difficulty in measuring chemical evolution is the need for rest-frame optical spectroscopy. My talk will focus on recent efforts to characterize low-mass and/or strongly star-forming galaxies, and examine their evolution across the past ten billion years. Using narrow-band imaging from the Subaru Deep Field and spectroscopy from 6-to-10 meter class telescopes, I have identified a population of extremely metal-poor galaxies at redshifts of 0.4 to 1 with detections of [OIII]4363. For their low stellar mass, I find that these galaxies have high specific SFRs (inverse ~100 Myr), high nuclear SFR surface densities, and have between one and four nearby companions within 100 kpc. I argue that galaxy-galaxy interactions are responsible for the lack of metals in the interstellar medium. In particular, these interactions can induce gravitational torques that drive metal-deficient gas from the outskirts of galaxies into the centers. I will also discuss our recent efforts to study the relationship between mass, metallicity, and SFR at z~1 from the NEWFIRM H-alpha Survey, and our current plans with Subaru's FMOS spectrograph to study the Mass-Metallicity-SFR relation at z~2.2 using more robust oxygen metallicity calibrations.

The correlations between galaxy properties and supermassive black hole mass motivated a numerous observational and theoretical studies. Nevertheless, our understanding of the origin of this connection is premature. In this talk, I will review the current status and limitation of the BH-galaxy scaling relations of active and quiescent galaxies at z~0, and cosmic evolution of the scaling relation based on our long-term study with HST imaging and Keck spectroscopy. In the second part of the talk, I will discuss the results from a census of ionized gas outflows, using a 22,000 local AGNs, and present the highlight of the follow-up integral field spectroscopy of the AGNs with strong outflows. Then, I will briefly discuss the connection between star formation and AGN activity based on AKARI and Herschel data, to constrain the interaction between BHs and star formation, using a large sample of local optical AGNs, and a small sample of X-ray AGNs at moderate redshift.

We present deep optical and near--infrared (NIR) UBVRIHKs imaging data for 24 blue compact galaxies (BCGs) and a volume--limited subsample of 21 UM emission line galaxies. The data contain luminous dwarf and intermediate-mass BCGs, as well as low-mass, faint and compact targets. Most galaxies are metal-poor, although a few have near-solar metallicities. We have analyzed isophotal and elliptical integration surface brightness and color profiles, extremely deep (uB< ~29 mag arcsec^-2) contour maps and RGB images for each galaxy in the sample, and provide a morphological classification where such is missing. We have measured the total galaxy colors, the colors of the underlying host galaxy, and the colors of the burst, and compare these to the predictions of new state-of-the-art spectral evolutionary models (SEMs) both with and without contribution by nebular emission. Synthetic disk tests are performed to verify that we can trace such faint components with negligible errors down to uB=28 mag arcsec^-2 and uK=23 mag arcsec^-2. Separating the burst from the underlying host, we find that regardless of the total luminosity the host galaxy has the properties of a low surface brightness (LSB) dwarf with MB>~-18. For a number of galaxies we discover a distinct LSB component dominant around and beyond the Holmberg radius. For the specific case of ESO400 43A&B we detect an optical bridge between the two companion galaxies at the uV~28th mag arcsec^-2 isophotal level. By examining the structural parameters (central surface brightness u0 and scale length hr) derived from two radial ranges typically assumed to be dominated by the underlying host galaxy, we demonstrate the importance of sampling the host well away from the effects of the burst. We find that u0 and hr of the BCGs host deviate from those of dwarf ellipticals (dE) and dwarf irregulars (dI) solely due to a strong burst contribution to the surface brightness profile almost down to the Holmberg radius. Structural parameters obtained from a fainter region, uB=26-28 mag arcsec^-2, are consistent with those of true LSB galaxies for the starbursting BCGs in our sample, and with dEs and dIs for the BCGs with less vigorous star formation. We further measure and analyse the A180 asymmetry and the concentration index C in all filters. A shift in the average A180 asymmetry is detected from optical to NIR. This shift appears correlated with the morphological class of the BCGs. Using the color-asymmetry relation, we identify some BCGs as undergoing mergers, which is confirmed by their morphological class. Though clearly separated from normal galaxies in the concentration--asymmetry parameter space, we find that it is not possible to distinguish luminous starbursting BCGs from the merely star forming low luminosity BCGs.

Raven will be the first Multi-Object Adaptive Optics (MOAO) technical and science demonstrator installed on an 8 m class telescope. Developed by the University of Victoria, in partnership with NAOJ, HIA and Tohoku University, Raven uses 3 NGSs and 1 LGS to reconstruct a 3D model of the turbulence above the telescope and offers the capability to correct two independent science FoVs of 4" within a 3.5' field of regard. Raven will be brought up to the Nasmyth IR plateform of Subaru Telescope in May 2014 for a first set of engineering test. In this talk, we will give a technical overview of the system and will introduce the science cases currently under development for the Raven project.

The CLASH observing program has produced a unique data set which allows the accurate calibration of a large set of galaxy cluster masses. The cosmological and astrophysical implications of these measurements extend far beyond HST-only science. To capitalize on the astronomy community's interest in the CLASH data products, our collaboration has assembled a team of experts across many different observational cluster probes, including: strong lensing, weak lensing, X-ray, and the Sunyaev-Zel'dovich Effect (SZE). By combining weak- and strong-lensing measurements, full cluster profiles can be constrained from the inner tens of kpc out to several Mpc. This has important implications in cross-probe analyses as different observational probes are sensitive to different regions of a cluster's mass profile. Another goal of the CLASH program is to characterize the level of hydrostatic mass bias in X-ray measurements. This is important as hydrostatic mass estimates are commonly used to calibrate X-ray and SZE cluster studies. In my talk, I will report on the status of several cross-probe scaling relations comparing the CLASH lensing masses and various baryonic cluster mass probes, including: optical richness, X-ray, and SZE observations of the full CLASH cluster catalog. The results of these investigations will be interesting for both large-scale surveys and individual cluster studies, when high quality lensing data is unavailable.

I will describe a campaign of imaging observations of the gravitationally lensed quasars from the SDSS database, using the Subaru Telescope Adaptive Optics (IRCS+AO188). Eighteen lensed quasars and two lensed quasar candidates were observed for 10-20 minutes, mostly in the laser guide star mode. The sample consists mostly of doubles, and one quad. The purpose of the campaign is to obtain accurate relative astrometry, photometry and lens shapes for each system, reveal detail unseen in existing low-resolution data, and constrain accurate mass models. Due to weather variability and low Strehl ratios ≲10%, separately observed stars do not constitute accurate PSF representations, and the PSF was built on target, either as a 2 Moffat analytical profile or as a hybrid (a core component from the observed quasar images, and analytical wings). I will describe the observations, data analysis and simulations, present new results on selected systems, and general results on the alignment and ellipticity of mass and light, as well as the mean radial mass profile of elliptical galaxies, from the combination of multiple samples.

will present an update to instrumentation activities at the Australian Astronomical Observatory. These will include: 1) First Light results from the High Efficiency and Resolution Multi Element Spectrograph (HERMES), a facility-class optical spectrograph for the AAT, designed primarily for the GALAH, Galactic Archeology Survey, the first major attempt to create a detailed understanding of galaxy formation and evolution by studying the history of our own galaxy, the Milky Way. The spectrograph uses VPH-gratings to achieve a spectral resolving power of 28,000 in standard mode and also provides a high resolution mode ranging between 40,000 to 50,000 using a slit mask. 2) The Gemini High-Resolution Optical SpecTrograph (GHOST) instrument is the newest instrument being developed for the Gemini telescopes, in a collaboration between the Australian Astronomical Observatory (AAO), the Herzberg Institute for Astrophisics (HIA) in Canada and the Australian National University (ANU). 3) New Fiber positioning Technologies: Starbugs for the TAIPAN Survey and Manifest for GMT as well as the Echidna Technology for DESI and 4Most 4) the SAMI survey 5) Future Instruments and new technology: Hector for the AAT, OH suppression fibers and more.

We investigate formation and structure of circumplanetary disks in order to understand formation processes of satellite formation around giant planets. We first examine structure of gas accretion from protoplanetary disks onto circumplanetary disks by using hydrodynamic simulation with nested grid method, which significantly enhances spacial resolution near the planet. Our detailed analysis of the gas accretion flow reveals the structure of the circumplanetary disks in detail and one of the most interesting features is that most of gas accretion onto circumplanetary disks occurs nearly vertically toward the disk surface from high altitude, not through the midplane. We also carry out orbital integration of particles rotating around the sun in order to understand how solid materials, which are necessary components of the satellites, rotating around the sun accrete onto circumplanetary disks under the influence of the gas accretion. We find that the accretion efficiency of the solid particles peaks around 10m-sized particles because energy dissipation of drag with circum-planetary disk gas in this size regime is most effective. We discuss the formation processes of Galilean satellites and find that solid to gas ratio in the solar nebula near the proto-Jovian orbit should be very high (~1) in order to explain the current features of the satellites.

I will discuss the large-scale distribution, evolution, and dynamics of giant molecular clouds (GMCs) in galaxies. The talk is mostly based on the results on M51, but I will also summarize recent results from the CARMA and Nobeyama Nearby-galaxies (CANON) CO 1-0 survey and the CO observations of the Milky Way. The standard, albeit simplistic, picture of ISM phases posits that GMCs are assembled in the spiral arm shocks from diffuse interarm HI gas and then photo-dissociated back into the atomic phase by OB star formation within the spiral arms. However, we are finding many GMCs both on spiral arms and in interarm regions, indicating their long lifetime comparable to galactic rotation timescale. The associations of GMCs (so-called GMAs) are found only on spiral arms, and thus, they are likely unbound, short-lived structures, being broken up across spiral arms. A molecular gas fraction stays high even in interarm regions. Therefore, the GMA destruction is not likely caused by stellar feedback such as strong UV radiation or supernovae, since they would destroy molecules as well as GMAs and GMCs. Instead, I will discuss a picture of dynamically-driven evolution -- strong shear motions in spiral arms cause the GMA destruction and trigger GMC evolution. On small scales, dense gas cores are expected to develop in GMCs through spiral arms, leading to star formation. I will also discuss evidence for such growth in nearby spiral galaxies and in the Milky Way.

We now stand firmly in the era of solid exoplanet detection via Kepler and other state of the art facilities. Yet the empirical characterization of these most intriguing planets is extremely challenging. Transit plus radial velocity information can yield planet mass and radius, and hence planet density, but the bulk composition remains degenerate and completely model-dependent. Currently, the abundances of a handful of exoplanet atmospheres can be estimated from transit spectroscopy, or observed directly via spectroscopy, but probing only the most tenuous outer layers of those planets. Fortunately, as demonstrated by Spitzer, AKARI, and complementary ground-based observations, debris disk-polluted white dwarfs can yield highly accurate information on the chemical structure of rocky minor planets (i.e. exo-asteroids), the building blocks of solid exoplanets. The white dwarf distills the planetary fragments, and provides powerful insight into the mass and chemical structure of the parent body. This archaeological method provides empirical data on the assembly and chemistry of exo-terrestrial planets that is unavailable for any planetary system orbiting a main-sequence star. In the Solar System, the asteroids (or minor planets) are leftover building blocks of the terrestrial planets, and we obtain their compositions -- and hence that of the terrestrial planets -- by studying meteorites. Similarly, one can infer the composition of exo-terrestrial planets by studying tidally destroyed and accreted asteroids at polluted white dwarfs. I will present ongoing, state of the art results using this unconventional technique, including ALMA Cycle 0 data and the lasting impact of infrared space missions like Spitzer and AKARI. Some highlights will include the recent detection of terrestrial-like debris in the Hyades star cluster, as well as the detection of water-rich planetesimals that may represent the building blocks of habitable exoplanets.

Galaxy evolution theories predict that massive galaxies are transformed over cosmic time through on-going star formation and mergers with other galaxies, but at the same time, a small fraction (<0.1%) should survive untouched till today. However, searches for such relic galaxies, useful windows to explore the early Universe, have been inconclusive to date: galaxies with masses and sizes like those observed at high redshift (M*>10^11 Msun; Re<1.5 kpc) have been found in the local Universe, but their stars are far too young for the galaxy to be a relic galaxy. In this talk, I will present the results from new spectroscopic data for NGC1277, a nearby galaxy that has recently caught the attention of the community due to its super massive black hole. Our analysis shows that NGC1277 fulfills all the criteria to be considered a relic galaxy: it is massive, compact and its star formation history along the structure of the galaxy shows that the stellar populations are uniformly old (>10 Gyr) with no evidence for more recent star formation episodes. Furthermore, the metallicity of their stars is super-solar and extremely alpha enriched, which suggests a very short formation time scale for the bulk of stars of this galaxy. This galaxy is, therefore, a serious candidate to be the first confirmed relic in the nearby Universe.

Star-forming galaxies become increasingly irregular at z > 2 with clumpy structures as well as enhancements of star formation activities. How do such distant clumpy galaxies evolve? In numerical simulations, the clumps can migrate toward the galaxy center as a result of their mutual interactions and of dynamical friction against the host disk, and coalesce into a young bulge. On the other hand, strong stellar feedback, parameterized by momentum-driven galactic winds, can disrupt clumps before migrating towards the galaxy centers. To give observational constraints on the fate of the clumps, we have identified a lot of clumpy galaxies from a narrow-band imaging survey of H-alpha emitters (HAEs) at z > 2 with MOIRCS on Subaru Telescope in the SXDF-CANDELS field, where the high-resolution near-infrared and optical images by WFC3/ACS on HST are both publicly available. Interestingly, the colors of clumps are often significantly different: we find the trends of having redder colors in the galactic nuclei compared to the off-center clumps. Moreover, some clumpy HAEs are detected with MIPS 24 um image, which strongly suggests that dusty starburst is occurring within these galaxies. Therefore, our result implies that the intense star formation is on-going in the red clump near the galaxy center. Dusty starburst activity in a nuclear clump supports the scenario that the clumps migrate to galactic center or merge with other clumps, and then such events induce an intense star-formation like a gas-rich merger process.

The Cosmic Infrared Background (CIB) as an integrated history of the early universe is important for the study of the Dark Ages, and it may include the light from the first stars at z~10. However, previous CIB measurements suffer from residual contamination from strong foreground emission (e.g. the zodiacal light). In this talk, our two projects for CIB observation will be introduced. One is the Cosmic Infrared Background Experiment (CIBER), that is a rocket experiment designed to study CIB. CIBER comprises four telescopes to observe the absolute spectrum and spatial fluctuations of CIB. CIBER has flown four times from 2009 to 2013, and we succeed good quality data acquisition. The other is our newly developed method for CIB observation: the Galilean satellite occulting method. In this method, we observe Galilean satellites eclipsed in the shadow of Jupiter as occulting disks at near-infrared wavelengths in order to detect the absolute CIB intensity without any zodiacal light subtraction error. The zodiacal light originates inside the orbit of Jupiter; since the Galilean satellites in eclipse shield all light beyond the Jovian orbit, they should be detected as 'dark spots' if the strong CIB implied by previous observations exists. The intensity deficit of this dark spot relative to the surrounding sky directly measures the strength of the CIB, free from any assumptions about the zodiacal light. We conducted several observations by this method with Spitzer, HST, and Subaru IRCS+AO.

The fast ion-molecule chemistry that occurs in the interstellar medium (ISM) is initiated by cosmic-ray ionization of both atomic and molecular hydrogen. Species that are near the beginning of the network of interstellar chemistry such as the oxygen-bearing ions OH+ and H2O+ can be useful probes of the cosmic-ray ionization rate. This parameter is of particular interest as, to some extent, it controls the abundances of several molecules. Using observations of OH+ and H2O+ made with HIFI on board Herschel through the PRISMAS and WISH key programs and the open time program OT1_dneufeld_1, we have inferred the cosmic-ray ionization rate of atomic hydrogen in multiple distinct clouds along 12 Galactic sight lines. These two molecules also allow us to determine the molecular hydrogen fraction (amount of hydrogen nuclei in H2 versus H) as OH+ and H2O+ (and H3O+ if observed) abundances are dependent on the competition between dissociative recombination with electrons and hydrogen abstraction reactions involving H2. Our observations of OH+ and H2O+ indicate environments where H2 accounts for less than 10% of the available hydrogen nuclei, suggesting that these species primarily reside in the diffuse, atomic ISM. Most previous estimates of the cosmic-ray ionization rate have relied on molecules that form in regions more dominated by molecular hydrogen---e.g., H3+ and HCO+---so these observations have allowed us to extend the investigation of the cosmic-ray flux into less explored environments. Average ionization rates in the diffuse, atomic ISM are on the order of a few times 10-16 s-1, with most values in specific clouds above or below this average by a factor of 3 or so. This result is in good agreement with the most up-to-date determination of the distribution of cosmic-ray ionization rates in diffuse molecular clouds as inferred from observations of H3+. Without question, Herschel has improved our overall understanding of interstellar chemistry and the ISM, especially in primarily neutral atomic clouds.

The New Horizons spacecraft will make the first flyby of the Pluto system on July 14th 2015. I will discuss our current knowledge of the system, and how the spacecraft instrumentation and planned observations will be used to revolutionize our understanding of Pluto and its moons. After the Pluto flyby, New Horizons will continue deeper into the Kuiper Belt, providing the chance to fly by one of the smaller and more representative members of the Kuiper Belt. I will also report on the progress of the search for flyby targets, and the key role in the search played by the Subaru telescope.

Photonic crystal, artificial periodic nanostructure of high and low refractive indices, is an attracting device for manufacturing focal-plane coronagraph masks. We have been developing an eight-octant phase mask (8OPM) and vector vortex mask based on the photonic-crystal technology. In this seminar, I will present laboratory demonstrations of the photonic-crystal coronagraph masks aimed at direct imaging of Earth-like exoplanets. In addition, I will also present our recent activities for installing the 8OPM coronagraph into the Subaru Coronagraphic Extreme AO (SCExAO).

The formation of proto-planetary disks begins during the earliest phase of the star formation process, while the nascent protostar is still surrounded by a dense envelope of gas and dust. Using sub/millimeter interferometry, we can probe through the dense envelope revealing the the protostellar disk. However, the properties of disks early in the protostellar phase are still quite uncertain as there are currently only a few clear examples. Understanding the early disks are important given that they set the initial conditions for planet formation and may play a role in binary star formation through fragmentation via gravitational instability. Moreover, the rotation curve of these protostellar disks reveal the masses of the protostars, an important parameter that has lacked observational constraint until recently. Probing deeper, we also find binaries in a few protostellar systems that with ~100 AU separations, a strong indication that the disks themselves are fragmenting early-on. But statistics are not yet good enough to know how binaries tend to form, whether through disk fragmentation or migration. Our ability to detect disks and binaries early in the protostellar phase has progressed to the point where a broad characterization is needed, necessitating a large survey that we are beginning to conduct with the VLA this fall toward all known protostars in the Perseus cloud. Moreover, the sensitivity of ALMA will make observations of disk kinematics routine toward protostars enabling masses of a large number of Class 0 protostars to be measured for the first time.

Pulsating stars are useful tracers of the Milky Way and nearby galaxies. However, survey of these stars in the Milky Way is far from complete mainly due to the large extinction towards the Galactic bulge and disk. We are conducting a photometric survey of pulsating stars using 1-m class telescopes, and we have discovered the objects in the obscured regions such as classical Cepheids near the Galactic center. In order to investigate the kinematics and chemical evolution of the Galaxy, we are carrying out spectroscopic observations of these new targets using IRCS and FMOS at SUBARU. In 2012, we used the IRCS to collect H-band spectra of the Galactic center Cepheids. I will discuss their kinematics and the connection to the nuclear stellar disk with a radius ~200 pc around the Galactic center.

Better measurements of Ho - the current expansion rate of the Universe, provide critical independent constraints on dark energy, spatial curvature of the Universe, neutrino physics, and validity of general relativity. The recent Planck results highlight the necessity of an independent determination of Ho at high accuracy.

The Mega-maser Cosmology Project (MCP) aims to determine the Hubble Constant at high accuracy by measuring the angular-diameter distance to galaxies in the Hubble Flow. The MCP has discovered 9 new mega-maser disks in Sy2 nuclei suitable for distance determination. A geometric distance measurement to a galaxy at 140 Mpc, via micro-arc-second astrometry of its circum-nuclear mega-maser disk, has been demonstrated. The current status of the MCP measurements of Ho, and future prospects, will be described.

The MCP also enables accurate determination of the central black-hole mass in mega-maser galaxies. The large intrinsic scatter of BH masses in a narrow range of the velocity dispersion in the mega-maser galaxy bulges raise questions about the validity of the well-known M-σ relation of BH mass and the spherical component of galaxies. The relationship of the thin Keplerian accretion disks delineated by the mega-masers with the obscuring material of the AGN will also be briefly discussed.

Time permitting, other key projects at the NRAO will be also described.

Understanding the structure and evolution of disks surrounding young low-mass stars is one of the key issues to study the process of planet formation. Nevertheless the overall properties of those disks are not yet well constrained by observations. Observation of molecular lines is a useful tool to constrain the disks physical structure, as different molecules sample different physical conditions.. Beside the abundant CO, several other molecules have been detected in the outer part of the disks in the millimetre domain (e.g. HCO+, H2CO, CS, HCN, CN...). In this talk I will present results obtained with APEX and the IRAM telescopes, and I will confront them to models of protoplanetary disks, in particular to the layered structure that is predicted by all chemical model so far.

Motivated by the discovery of galaxies emitting surprisingly strong Lyman continuum (lambda_rest<900A), I have proposed a new spectral model of galaxies, taking into account the escape of stellar and nebular Lyman continua from galaxies. Beyond the classical Stromgren sphere model, I considered matter bounded nebulae and the escape of nebular recombination Lyman continuum. The model predicts a spectral bump just below the Lyman limit, not the break usually expected. Even with this Lyman "bump" model, however, the observed strength of the Lyman continuum of some galaxies may require unusual stellar populations which emit more strong Lyman continuum such as extremely metal-poor or even metal-free stars.

We have used observations from the Herschel space observatory and the IRAM Plateau de Bure interferometry to characterize the evolving properties of star forming galaxies up to a redshift of about 2, including their star formation rates and gas content (hence star formation efficiencies). The most interesting outcome is that their evolution can be quite well described with a simplified empirical framework where stellar mass is the primary physical parameter, with the differentiation between disk like growth and merging triggered star formation is a first order correction. In this 2SF-mode framework we can account for the IR luminosity function and multi-frequency galaxy counts, the cosmic evolution of dust temperatures, and the luminosity of the AGNs they contain. Ultimately, it appears that the availibility of gas reservoirs is the most important ingredient regulating the cosmic growth of galaxies and of their supermassive black holes.

Galaxy clusters are the largest and youngest gravitationally bound system among the hierarchical structures in the universe. Dynamical studies of clusters have revealed that some systems are still forming and unrelaxed. X-ray studies of velocity structures of the intracluster medium is one of the primary goals for future X-ray missions. High resolution spectroscopies will provide measurements of energy distributions not only in thermal but also in kinematic forms. We have demonstrated gas motions based on the Suzaku observations of a X-ray bright merging cluster, Abell2256, by detecting a motion of a sub component with a velocity of about 1500 km/s for the first time by X-ray. In addition, I will introduce our cluster project based on X-ray and gravitational lensing (Subaru) observations. This project provides comparison between X-ray and lensing mass estimates and hence probes dynamical state at cluster outer regions. Following Suzaku, Chandra, XMM-Newton and others, the next international X-ray mission, ASTRO-H, to be launched in 2014, will expand our understanding of the evolution of clusters and large scale structures. I will give some future prospects with the ASTRO-H.

Attenuation of gamma-ray burst (GRB) afterglow is one important topic to understand GRB environment and GRB progenitor. (1) As long-duration GRBs are related to star formation, afterglow absorption by the surrounding medium in GRB host galaxy is possible. I apply one galaxy evolution model to investigate some properties of GRB host galaxies. The absorption of GRB X-ray/optical afterglow is also achieved. (2) I introduce the case of "dark" property shown in short-duration GRB afterglow. I stress the observational importance to the host galaxies of dark short GRBs. Some possible explanations to the "dark" property of short GRB afterglow are discussed as well.

We present two case studies of host galaxies of GRB 080325 and 100418A observed with Subaru telescope. We obtained near-infrared and optical spectra of GRB 080325 and 100418A hosts respectively. The metallicites of the hosts are estimated to be 12+log(O/H)=8.75 and 8.8 (KK04) by using emission-line diagnostics. Although these metallicites are comparable to or below the mass-metallisity relations explored for typical star-forming galaxies at each redshift, these clearly exceed the previously proposed critical metallicity below which GRBs occur, suggesting possible high-metallicity environment around GRBs. Because the single star scenario of GRB (massive single star explosion) requires low metallicity environment, these GRBs do not match up with such model. One possible origin is binary-star merger scenario for long GRBs; GRBs can occur even in high metallicity environment.