大栗 真宗

Abell 2146 consists of two galaxy clusters that have recently collided close to the plane of the sky, and it is unique in showing two large shocks on Chandra X-ray Observatory images. With an early stage merger, shortly after first core passage, one would expect the cluster galaxies and the dark matter to be leading the X-ray emitting plasma. In this regard, the cluster Abell 2146-A is very unusual in that the X-ray cool core appears to lead, rather than lag, the brightest cluster galaxy (BCG) in their trajectories. Here we present a strong-lensing analysis of multiple-image systems identified on Hubble Space Telescope images. In particular, we focus on the distribution of mass in Abell 2146-A in order to determine the centroid of the dark matter halo. We use object colours and morphologies to identify multiple-image systems; very conservatively, four of these systems are used as constraints on a lens mass model. We find that the centroid of the dark matter halo, constrained using the strongly lensed features, is coincident with the BCG, with an offset of approximate to 2 kpc between the centres of the dark matter halo and the BCG. Thus from the strong-lensing model, the X-ray cool core also leads the centroid of the dark matter in Abell 2146-A, with an offset of approximate to 30 kpc.

We report the discovery of a very bright (r =20.16), highly magnified, and yet intrinsically very luminous Ly alpha emitter (LAE) at z = 2.82. This system comprises four images in the observer plane with a maximum separation of similar to 6" and it is lensed by a z = 0.55 massive early-type galaxy. It was initially identified in the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey for GALaxy-Ly alpha EmitteR sYstems survey, and follow-up imaging and spectroscopic observations using the Gran Telescopio Canarias and William Herschel Telescope confirmed the lensing nature of this system. A lens model using a singular isothermal ellipsoid in an external shear field reproduces the main features of the system quite well, yielding an Einstein radius of 2".95 +/- 0"10, and a total magnification factor for the LAE of 8.8 +/- 0.4. This LAE is one of the brightest and most luminous galaxy-galaxy strong lenses known. We present initial imaging and spectroscopy showing the basic physical and morphological properties of this lensed system.

We present a list of galaxy-scale lens candidates including a highly probable interacting galaxy-scale lens in the Hyper Suprime-Cam (HSC) imaging survey. We combine HSC imaging with the blended-spectra catalog from the Galaxy And Mass Assembly (GAMA) survey to identify lens candidates, and use lens mass modeling to confirm the candidates. There are 45 matches between the HSC S14A_0b imaging data release and the GAMA catalog. We separate lens and lensed arcs using color information, and exclude those candidates with small image separations (<.'' 10, estimated with the lens/source redshifts from the GAMA survey) that are not easily resolved with ground-based imaging. After excluding these, we find 10 probable lens systems. There is one system with an interacting galaxy pair, HSC J084928+000949, that has a valid mass model. We predict the total mass enclosed by the Einstein radius of similar to 0.'' 72 (similar to 1.65 kpc) for this new expected lens system to be similar to 10(10.59) M-circle dot. Using the photometry in the grizy bands of the HSC survey and stellar population synthesis modeling with a Salpeter stellar initial mass function, we estimate the stellar mass within the Einstein radius to be similar to 10(10.46) M-circle dot. We thus find a dark matter mass fraction within the Einstein radius of similar to 25%. Further spectroscopy or high-resolution imaging would allow confirmation of the nature of these lens candidates. The particular system with the interacting galaxy pair, if confirmed, would provide an opportunity to study the interplay between dark matter and stars as galaxies build up through hierarchical mergers.

We present Hubble Space Telescope F606W-band imaging observations of 21 galaxy-Ly alpha emitter lens candidates in the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey (BELLS) for the. GALaxy-Ly alpha EmitteR sYstems (BELLS GALLERY) survey. Seventeen systems are confirmed to be definite lenses with unambiguous evidence of multiple imaging. The lenses are primarily massive early-type galaxies (ETGs) at redshifts of approximately 0.55, while the lensed sources are Ly alpha emitters (LAEs) at redshifts from two to three. Although most of the lens systems are well fit by smooth lens models consisting of singular isothermal ellipsoids in an external shear field, a thorough exploration of dark substructures in the lens galaxies is required. The Einstein radii of the BELLS GALLERY lenses are, on average, 60% larger than those of the BELLS lenses because of the much higher source redshifts. This will allow for. a detailed investigation of the radius evolution of the mass profile in ETGs. With the aid of the average similar to 13x lensing magnification, the LAEs are frequently resolved into individual star-forming knots with a wide range of properties. They have characteristic sizes from less than 100 pc to several kiloparsecs, rest-frame far-UV apparent AB magnitudes from 29.6 to 24.2, and typical projected separations of 500 pc to 2 kpc.

We present the application of the pseudo-spectrum method to galaxy-galaxy lensing. We derive explicit expressions for the pseudo-spectrum analysis of the galaxy-shear cross-spectrum, which is the Fourier space counterpart of the stacked galaxy-galaxy lensing profile. The pseudo-spectrum method corrects observational issues such as the survey geometry, masks of bright stars and their spikes, and inhomogeneous noise, which distort the spectrum and also mix the E-mode and the B-mode signals. Using ray-tracing simulations in N-body simulations including realistic masks, we confirm that the pseudo-spectrum method successfully recovers the input galaxy-shear cross-spectrum. We also show that the galaxy-shear cross-spectrum has an excess covariance relative to the Gaussian covariance at small scales (k greater than or similar to 1h Mpc(-1)) where the shot noise is dominated in the Gaussian approximation. We find that the excess is consistent with the expectation from the halo sample variance (HSV), which originates from the matter fluctuations at scales larger than the survey area. We apply the pseudo-spectrum method to the observational data of Canada-France-Hawaii Telescope Lensing survey shear catalogue and three different spectroscopic samples of Sloan Digital Sky Survey Luminous Red Galaxy, and Baryon Oscillation Spectroscopic Survey CMASS and LOWZ galaxies. The galaxy-shear cross-spectra are significantly detected at the level of 7-10 sigma using the analytic covariance with the HSV contribution included. We also confirm that the observed spectra are consistent with the halo model predictions with the halo occupation distribution parameters estimated from previous work. This work demonstrates the viability of galaxy-galaxy lensing analysis in the Fourier space.

We report the serendipitous discovery of HSC J142449-005322, a double source plane lens system in the Hyper Suprime-Cam Subaru Strategic Program. We dub the system Eye of Horus. The lens galaxy is a very massive early-type galaxy with stellar mass of similar to 7 x 10(11) M-circle dot located at z(L) = 0.795. The system exhibits two arcs/rings with clearly different colors, including several knots. We have performed spectroscopic follow-up observations of the system with FIRE on Magellan. The outer ring is confirmed at z(S2) = 1.988 with multiple emission lines, while the inner arc and counterimage is confirmed at z(S1) = 1.302. This makes it the first double source plane system with spectroscopic redshifts of both sources. Interestingly, redshifts of two of the knots embedded in the outer ring are found to be offset by Delta z = 0.002 from the other knots, suggesting that the outer ring consists of at least two distinct components in the source plane. We perform lens modeling with two independent codes and successfully reproduce the main features of the system. However, two of the lensed sources separated by similar to 0.7 arcsec cannot be reproduced by a smooth potential, and the addition of substructure to the lens potential is required to reproduce them. Higher-resolution imaging of the system will help decipher the origin of this lensing feature and potentially detect the substructure.

We show that the projected number density profiles of Sloan Digital Sky Survey photometric galaxies around galaxy clusters display strong evidence for the splashback radius, a sharp halo edge corresponding to the location of the first orbital apocenter of satellite galaxies after their infall. We split the clusters into two subsamples with different mean projected radial distances of their members, < R-mem >, at fixed richness and redshift. The sample with smaller < R-mem > has a smaller ratio of the splashback radius to the traditional halo boundary R-200m than the subsample with larger < R-mem >, indicative of different mass accretion rates for these subsamples. The same subsamples were recently used by Miyatake et al. to show that their large-scale clustering differs despite their similar weak lensing masses, demonstrating strong evidence for halo assembly bias. We expand on this result by presenting a 6.6 sigma difference in the clustering amplitudes of these samples using cluster-photometric galaxy cross-correlations. This measurement is a clear indication that halo clustering depends on parameters other than halo mass. If < R-mem > is related to the mass assembly history of halos, the measurement is a manifestation of the halo assembly bias. However, our measured splashback radii are smaller, while the strength of the assembly bias signal is stronger, than the predictions of collisionless. cold dark matter simulations. We show that dynamical friction, cluster mis-centering, or projection effects are not likely to be the sole source of these discrepancies. However, further investigations regarding unknown catastrophic weak lensing or cluster identification systematics are warranted.

We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey GALaxy-Ly alpha EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Ly alpha emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure-mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BELLS, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy-LAE candidates selected from approximate to 1.4 x 10(6) galaxy spectra in the BOSS of the Sloan Digital Sky Survey III. These systems consist of massive galaxies at redshifts of approximately 0.5 strongly lensing LAEs at redshifts from 2-3. The compact nature of LAEs makes them an ideal probe of dark substructures, with a substructure-mass sensitivity that is unprecedented in other optical strong-lens samples. The magnification effect from lensing will also reveal the structure of LAEs below 100 pc scales, providing a detailed look at the sites of the most concentrated unobscured star formation in the universe. The source code used for candidate selection is available for download as a part of this release.

We present the results of an imaging observation campaign conducted with the Subaru Telescope adaptive optics system (IRCS+A0188) on 28 gravitationally lensed quasars and candidates (23 doubles, 1 quad, 1 possible triple, and 3 candidates) from the SDSS Quasar Lens Search. We develop a novel modelling technique that fits analytical and hybrid point spread functions (PSFs), while simultaneously measuring the relative astrometry, photometry, as well as the lens galaxy morphology. We account for systematics by simulating the observed systems using separately observed PSF stars. The measured relative astrometry is comparable with that typically achieved with the Hubble Space Telescope, even after marginalizing over the PSF uncertainty. We model for the first time the quasar host galaxies in five systems, without a priori knowledge of the PSF, and show that their luminosities follow the known correlation with the mass of the supermassive black hole. For each system, we obtain mass models far more accurate than those previously published from low-resolution data, and we show that in our sample of lensing galaxies the observed light profile is more elliptical than the mass, for ellipticity greater than or similar to 0.25. We also identify eight doubles for which the sources of external and internal shear are more reliably separated, and should therefore be prioritized in monitoring campaigns aimed at measuring time delays in order to infer the Hubble constant.

Gravitational waves from inspiraling compact binaries are known to be an excellent absolute distance indicator, yet it is unclear whether electromagnetic counterparts of these events are securely identified for measuring their redshifts, especially in the case of black hole-black hole mergers such as the one recently observed with the Advanced LIGO. We propose to use the cross-correlation between spatial distributions of gravitational wave sources and galaxies with known redshifts as an alternative means of constraining the distance-redshift relation from gravitational waves. In our analysis, we explicitly include the modulation of the distribution of gravitational wave sources due to weak gravitational lensing. We show that the cross-correlation analysis in next-generation observations will be able to tightly constrain the relation between the absolute distance and the redshift and therefore constrain the Hubble constant as well as dark energy parameters.

We conduct precise strong lensing mass modeling of four Hubble Frontier Field (HFF) clusters, Abell 2744, MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.6+2223, for which HFF imaging observations are completed. We construct a refined sample of more than 100 multiple images for each cluster by taking advantage of the full-depth HFF images, and conduct mass modeling using the GLAFIC software, which assumes simply parametrized mass distributions. Our mass modeling also exploits a magnification constraint from the lensed SN Ia H14F14Tom for Abell 2744 and positional constraints from the multiple images Sl S4 of the lensed supernova SN Refsdal for MACS J1149.6+2223. We find that our best -fitting mass models reproduce the observed image positions with rms errors of 0/14, which are smaller than rms errors in previous mass modeling that adopted similar numbers of multiple images. Our model predicts a new image of SN Refsdal with a relative time delay and magnification that are fully consistent with a recent detection of reappearance. We then construct catalogs of z similar to 6-9 dropout galaxies behind the four clusters and estimate magnification factors for these dropout galaxies with our best -fitting mass models. The dropout sample from the four cluster fields contains 120 galaxies at z > 6, about 20 of which are predicted to be magnified by a factor of more than 10. Some of the high-redshift galaxies detected in the HFF have lensing-corrected magnitudes of M-UV, 15 to -14. Our analysis demonstrates that the HFF data indeed offer an ideal opportunity to study faint high-redshift galaxies. All lensing maps produced from our mass modeling will be made available on the Space Telescope Science Institute website (https://archive. stsci.edu/prepds/frontier/lensmodels/).

We report the discovery of 13 confirmed two-image quasar lenses from a systematic search for gravitationally lensed quasars in the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). We adopted a methodology similar to that used in the SDSS Quasar Lens Search (SQLS). In addition to the confirmed lenses, we report 11 quasar pairs with small angular separations (less than or similar to 2 arcsec) confirmed from our spectroscopy, which are either projected pairs, physical binaries, or possibly quasar lens systems whose lens galaxies have not yet been detected. The newly discovered quasar lens system, SDSS J1452+4224 at z(s) approximate to 4.8 is one of the highest redshift multiply imaged quasars found to date. Furthermore, we have over 50 good lens candidates yet to be followed up. Owing to the heterogeneous selection of BOSS quasars, the lens sample presented here does not have a well-defined selection function.

Radio emission from radio-quiet quasars may be due to star formation in the quasar host galaxy, to a jet launched by the supermassive black hole, or to relativistic particles accelerated in a wide-angle radiatively driven outflow. In this paper, we examine whether radio emission from radio-quiet quasars is a byproduct of star formation in their hosts. To this end, we use infrared spectroscopy and photometry from Spitzer and Herschel to estimate or place upper limits on star formation rates in hosts of similar to 300 obscured and unobscured quasars at z < 1. We find that low-ionization forbidden emission lines such as [ Ne (II)] and [ Ne (III)] are likely dominated by quasar ionization and do not provide reliable star formation diagnostics in quasar hosts, while polycyclic aromatic hydrocarbon (PAH) emission features may be suppressed due to the destruction of PAH molecules by the quasar radiation field. While the bolometric luminosities of our sources are dominated by the quasars, the 160 mu m fluxes are likely dominated by star formation, but they too should be used with caution. We estimate median star formation rates to be 6-29 M-circle dot yr(-1), with obscured quasars at the high end of this range. This star formation rate is insufficient to explain the observed radio emission from quasars by an order of magnitude, with log (L-radio, (obs)/ L-radio, (SF)) = 0.6-1.3 depending on quasar type and star formation estimator. Although radio-quiet quasars in our sample lie close to the 8-1000 mu m infrared/radio correlation characteristic of the star-forming galaxies, both their infrared emission and their radio emission are dominated by the quasar activity, not by the host galaxy.

Supernova "Refsdal," multiply imaged by cluster MACS1149.5+2223, represents a rare opportunity to make a true blind test of model predictions in extragalactic astronomy, on a timescale that is short compared to a human lifetime. In order to take advantage of this event, we produced seven gravitational lens models with five independent methods, based on Hubble Space Telescope (HST) Hubble Frontier Field images, along with extensive spectroscopic follow-up observations by HST, the Very Large and the Keck Telescopes. We compare the model predictions and show that they agree reasonably well with the measured time delays and magnification ratios between the known images, even though these quantities were not used as input. This agreement is encouraging, considering that the models only provide statistical uncertainties, and do not include additional sources of uncertainties such as structure along the line of sight, cosmology, and the mass sheet degeneracy. We then present the model predictions for the other appearances of supernova "Refsdal." A future image will reach its peak in the first half of 2016, while another image appeared between 1994 and 2004. The past image would have been too faint to be detected in existing archival images. The future image should be approximately one-third as bright as the brightest known image (i.e., mag at peak and mag six months before peak), and thus detectable in single-orbit HST images. We will find out soon whether our predictions are correct.

The discrepancy between the amplitudes of matter fluctuations inferred from Sunyaev-Zel'dovich (SZ) cluster number counts and the measurement of temperature and polarization anisotropies of the cosmic microwave background (CMB) measured by the Planck satellite can be reconciled if the local universe is embedded in an underdense region as shown by Lee, 2014. Here using a simple void model assuming the open Friedmann-Robertson-Walker geometry and a Markov Chain Monte Carlo technique, we investigate how deep the local underdense region needs to be to resolve this discrepancy. Such local void, if it exists, predicts the local Hubble parameter value that is different from the global Hubble constant. We derive the posterior distribution of the local Hubble parameter from a joint fitting of the Planck CMB data and SZ cluster number counts assuming the simple void model. We show that the predicted local Hubble parameter value of H-loc = 70.1 +/- 0.34 km s(-1) Mpc(-1) is in better agreement with direct local Hubble parameter measurements, indicating that the local void model may provide provide a consistent solution to the cluster number counts and Hubble parameter discrepancies.

We present spatially resolved properties of molecular gas and dust in a gravitationally lensed submillimeter galaxy H-ATLAS J090311.6+003906 (SDP. 81) at z = 3.042 revealed by the Atacama Large Millimeter/submillimeter Array (ALMA). We identified 14 molecular clumps in the CO(5-4) line data. The surface density of molecular gas (Sigma(H2)) and star-formation rate (Sigma(SFR)) of the clumps are more than three orders of magnitude higher than those found in local spiral galaxies. The clumps are placed in the "burst" sequence in the Sigma(H2) - Sigma(SFR) plane, suggesting that z similar to 3 molecular clumps follow the star-formation law derived for local starburst galaxies. With our gravitational lens model, the positions in the source plane are derived for the molecular clumps, dust clumps, and stellar components identified in the Hubble Space Telescope image. The molecular and dust clumps are confined within a similar to 2 kpc region, while the spatial extent of the stellar components is as large as similar to 6 kpc and offset toward the west. The molecular clumps have a systematic velocity gradient in the north-south direction, which may indicate a rotating gas disk. One possible scenario is that the components of molecular gas, dust, and stars are distributed in a several-kpc-scale rotating disk, and the stellar emission is heavily obscured by dust in the central star-forming region. Alternatively, SDP. 81 can be explained by a merging system, where dusty starbursts occur in the region where the two galaxies collide, surrounded by tidal features traced in the stellar components.

We report the detailed modeling of the mass profile of a z = 0.2999 massive elliptical galaxy using 30 milli-arcsecond resolution 1mm Atacama Large Millimeter/submillimeter Array (ALMA) images of the galaxy-galaxy lensing system SDP.81. The detailed morphology of the lensed multiple images of the z = 3.042 infrared-luminous galaxy, which is found to consist of tens of less than or similar to 100 pc-sized star-forming clumps embedded in a similar to 2kpc disk, are well reproduced by a lensing galaxy modeled by an isothermal ellipsoid with a 400 pc core. The core radius is consistent with that of the visible stellar light, and the mass-to-light ratio of similar to 2M(circle dot)L(circle dot)(-1) is comparable to the locally measured value, suggesting that the inner 1 kpc region is dominated by luminous matter. The position of the predicted mass centroid is consistent to within similar or equal to 30 mas with a non-thermal source detected with ALMA, which likely traces an active galactic nucleus of the foreground elliptical galaxy. While the black hole mass and the core radius of the elliptical galaxy are degenerate, a point source mass of > 3 x 10(8)M(circle dot) mimicking a supermassive black hole is required to explain the non-detection of a central image of the background galaxy. The required mass is consistent with the prediction from the well-known correlation between black hole mass and host velocity dispersion. Our analysis demonstrates the power of high resolution imaging of strong gravitational lensing for studying the innermost mass profile and the central supermassive black hole of distant elliptical galaxies.

Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. Current and upcoming imaging surveys will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we built a robot, CHITAH, that hunts for lensed quasars by modeling the configuration of the multiple quasar images. Specifically, given an image of an object that might be a lensed quasar, CHITAH first disentangles the light from the supposed lens galaxy and the light from the multiple quasar images based on color information. A simple rule is designed to categorize the given object as a potential four-image (quad) or two-image (double) lensed quasar system. The configuration of the identified quasar images is subsequently modeled to classify whether the object is a lensed quasar system. We test the performance of CHITAH using simulated lens systems based on the Canada-France-Hawaii Telescope Legacy Survey. For bright quads with large image separations (with Einstein radius r(ein) > 1". 1) simulated using Gaussian point-spread functions, a high true-positive rate (TPR) of similar to 90% and a low false-positive rate of similar to 3% show that this is a promising approach to search for new lens systems. We obtain high TPR for lens systems with r(ein) greater than or similar to 0".5, so the performance of CHITAH is set by the seeing. We further feed a known gravitational lens system, COSMOS 5921 + 0638, to CHITAH, and demonstrate that CHITAH is able to classify this real gravitational lens system successfully. Our newly built CHITAH is omnivorous and can hunt in any ground-based imaging surveys.

We present properties of moderately massive clusters of galaxies detected by the newly developed Hyper Suprime-Cam on the Subaru telescope using weak gravitational lensing. Eight peaks exceeding a signal-to-noise ratio (S/N) of 4.5 are identified on the convergence S/N map of a 2.3 deg(2) field observed during the early commissioning phase of the camera. Multi-color photometric data are used to generate optically selected clusters using the Cluster finding algorithm based on the Multiband Identification of Red-sequence galaxies algorithm. The optical cluster positions were correlated with the peak positions from the convergence map. All eight significant peaks have optical counterparts. The velocity dispersion of clusters is evaluated by adopting the Singular Isothemal Sphere fit to the tangential shear profiles, yielding virial mass estimates, M-500c, of the clusters which range from 2.7 x 10(13) to 4.4 x 10(-14) M-circle dot. The number of peaks is considerably larger than the average number expected from Lambda CDM cosmology but this is not extremely unlikely if one takes the large sample variance in the small field into account. We could, however, safely argue that the peak count strongly favors the recent Planck result suggesting a high sigma(8) value of 0.83. The ratio of stellar mass to the dark matter halo mass shows a clear decline as the halo mass increases. If the gas mass fraction, f(g), in halos is universal, as has been suggested in the literature, the observed baryon mass in stars and gas shows a possible deficit compared with the total baryon density estimated from the baryon oscillation peaks in anisotropy of the cosmic microwave background.

The TMT Detailed Science Case describes the transformational science that the Thirty Meter Telescope will enable. Planned to begin science operations in 2024, TMT will open up opportunities for revolutionary discoveries in essentially every field of astronomy, astrophysics and cosmology, seeing much fainter objects much more clearly than existing telescopes. Per this capability, TMT's science agenda fills all of space and time, from nearby comets and asteroids, to exoplanets, to the most distant galaxies, and all the way back to the very first sources of light in the Universe. More than 150 astronomers from within the TMT partnership and beyond offered input in compiling the new 2015 Detailed Science Case. The contributing astronomers represent the entire TMT partnership, including the California Institute of Technology (Caltech), the Indian Institute of Astrophysics (IIA), the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC), the National Astronomical Observatory of Japan (NAOJ), the University of California, the Association of Canadian Universities for Research in Astronomy (ACURA) and US associate partner, the Association of Universities for Research in Astronomy (AURA).

We investigate the sizes of z similar to 6-8 dropout galaxies using the complete data of the Abell 2744 cluster and parallel fields in the Hubble Frontier Fields program. By directly fitting light profiles of observed galaxies with lensing-distorted Sersic profiles on the image plane with the glafic software, we accurately measure intrinsic sizes of 31 z similar to 6-7 and 8z similar to 8 galaxies, including those as faint as M-UV similar or equal to -16.6. We find that half-light radii r(e) positively correlates with UV luminosity at each redshift, although the correlation is not very tight. The largest (r(e) > 0.8 kpc) galaxies are mostly red in UV color while the smallest (r(e) < 0.08 kpc) ones tend to be blue. We also find that galaxies with multiple cores tend to be brighter. Combined with previous results at 2.5 less than or similar to z less than or similar to 12, our result confirms that the average r(e) of bright ((0.3-1) L-z=3*) galaxies scales as r(e) proportional to (1 + z)(-m) with m = 1.24 +/- 0.1. We find that the ratio of r(e) to virial radius is virtually constant at 3.3 +/- 0.1% over a wide redshift range, where the virial radii of hosting dark matter halos are derived based on the abundance matching. This constant ratio is consistent with the disk formation model by Mo et al. with j(d) similar to m(d), where j(d) and m(d) are the fractions of the angular momentum and mass within halos confined in the disks. A comparison with various types of local galaxies indicates that our galaxies are most similar to circumnuclear star-forming regions of barred galaxies in the sense that a sizable amount of stars are forming in a very small area.

We construct a mass model of the cluster MACS J1149.6+2223 to study the expected properties of multiple images of SN Refsdal, the first example of a gravitationally lensed supernova with resolved multiple images recently reported by Kelly et al. We find that the best-fitting model predicts six supernova images in total, i.e. two extra images in addition to the observed four Einstein cross supernova images S1-S4. One extra image is predicted to have appeared about 17 years ago, whereas the other extra image is predicted to appear in about one year from the appearance of S1-S4, which is a testable prediction with near-future observations. The predicted magnification factors of individual supernova images range from similar to 18 for the brightest image to similar to 4 for the faint extra images. Confronting these predictions with future observations should provide an unprecedented opportunity to improve our understanding of cluster mass distributions.

We report the discovery of a gravitationally lensed hyperluminous infrared galaxy (intrinsic LIR ≈ 1013 L⊙) with strong radio emission (intrinsic L1.4 GHz ≈1025 W Hz-1) at z=2.553. The source was identified in the citizen science project SPACE WARPS through the visual inspection of tens of thousands of iJKs colour composite images of luminous red galaxies (LRGs), groups and clusters of galaxies and quasars. Appearing as a partial Einstein ring (re ≈ 3 arcsec) around an LRG at z = 0.2, the galaxy is extremely bright in the sub-millimetre for a cosmological source, with the thermal dust emission approaching 1 Jy at peak. The redshift of the lensed galaxy is determined through the detection of the CO(3 → 2) molecular emission line with the Large Millimetre Telescope's Redshift Search Receiver and through [O III] and Ha line detections in the near-infrared from Subaru/Infrared Camera and Spectrograph. We have resolved the radio emission with high-resolution (300-400 mas) eMERLIN L-band and Very Large Array C-band imaging. These observations are used in combination with the nearinfrared imaging to construct a lens model, which indicates a lensing magnification of μ ≈ 10. The source reconstruction appears to support a radio morphology comprised of a compact (<250 pc) core and more extended component, perhaps indicative of an active nucleus and jet or lobe.

How well can we infer host dark matter halo masses of individual galaxies? Based on the halo occupation distribution framework, we analytically compute the number of neighboring galaxies within a cylinder of some redshift interval and radius in transverse comoving distance. The result is used to derive the conditional probability distribution function (PDF) of the host halo mass of a galaxy, given the neighboring galaxy counts. We compare our analytic results with those obtained using a realistic mock galaxy catalog, finding reasonable agreements. We find the optimal cylinder radius to be similar to 0.5-1 h(-1) Mpc for the inference of halo masses. The PDF is generally broad, and sometimes has two peaks at low-and high-mass regimes. because of the effect of chance projection along the line of sight. Potential applications and extensions of the new theoretical framework developed herein are also discussed.

Studies of high-redshift galaxies behind the cores of mass clusters require the correction of gravitational lensing effects. We present our approach to estimate shapes, magnitudes, and the selection effect of high-redshift galaxies in the image plane, which allows us to include not only lensing magnifications but also lensing distortions and image multiplications. For this purpose we construct new mass models for the Frontier Fields clusters using the public software glafic. We present some results on faint-end slopes of the luminosity function and the size evolution of high-redshift galaxies from the analysis of Frontier Fields clusters.

We present comprehensive analyses of faint dropout galaxies up to z similar to 10 with the first full-depth data set of the A2744 lensing cluster and parallel fields observed by the Hubble Frontier Fields (HFF) program. We identify 54 dropouts at z similar to 5-10 in the HFF fields and enlarge the size of the z similar to 9 galaxy sample obtained to date. Although the number of highlymagnified (mu similar to 10) galaxies is small because of the tiny survey volume of strong lensing, our study reaches the galaxies' intrinsic luminosities comparable to the deepest-field HUDF studies. We derive UV luminosity functions with these faint dropouts, carefully evaluating by intensive simulations the combination of observational incompleteness and lensing effects in the image plane, including magnification, distortion, and multiplication of images, with the evaluation of mass model dependencies. Our results confirm that the faint-end slope, alpha, is as steep as -2 at z similar to 6-8 and strengthen the evidence for the rapid decrease of UV luminosity densities, rho(UV), at z > 8 from the large z similar to 9 sample. We examine whether the rapid rho(UV) decrease trend can be reconciled with the large Thomson scattering optical depth, tau(e), measured by cosmic microwave background experiments, allowing a large space of free parameters, such as an average ionizing photon escape fraction and a stellar-population-dependent conversion factor. No parameter set can reproduce both the rapid rho(UV) decrease and the large tau(e). It is possible that the rho(UV) decrease moderates at z greater than or similar to 11, that the free parameters significantly evolve toward high z, or that there exist additional sources of reionization such as X-ray binaries and faint active galactic nuclei.

We present the result of Subaru Telescope multiband adaptive optics observations of the complex gravitationally lensed quasar SDSS J1405+0959, which is produced by two lensing galaxies. These observations reveal dramatically enhanced morphological detail, leading to the discovery of an additional object 0.26 arcsec from the secondary lensing galaxy, as well as three collinear clumps located in between the two lensing galaxies. The new object is likely to be the third quasar image, although the possibility that it is a galaxy cannot be entirely excluded. If confirmed via future observations, it would be the first three-image lensed quasar produced by two galaxy lenses. In either case, we show based on gravitational lensing models and photometric redshift that the collinear clumps represent merging images of a portion of the quasar host galaxy, with a magnification factor of similar to 15-20, depending on the model.

We study the geometry and the internal structure of the outflowing wind from the accretion disk of a quasar by observing multiple sightlines with the aid of strong gravitational lensing. Using Subaru/High Dispersion Spectrograph, we performed high-resolution (R similar to 36,000) spectroscopic observations of images A and B of the gravitationally lensed quasar SDSS J1029+2623 (at z(em) similar to 2.197) whose image separation angle, theta similar to 22 ''.5, is the largest among those discovered so far. We confirm that the difference in absorption profiles in images A and B discovered by Misawa et al. has remained unchanged since 2010, implying the difference is not due to time variability of the absorption profiles over the delay between the images, Delta t similar to 744 days, but rather due to differences along the sightlines. We also discovered a time variation of CIV absorption strength in both images A and B due to a change in the ionization condition. If a typical absorber's size is smaller than its distance from the flux source by more than five orders of magnitude, it should be possible to detect sightline variations among images of other smaller separation, galaxy-scale gravitationally lensed quasars.

We present a new algorithm, CAMIRA, to identify clusters of galaxies in wide-field imaging survey data. We base our algorithm on the stellar population synthesis model to predict colours of red sequence galaxies at a given redshift for an arbitrary set of bandpass filters, with additional calibration using a sample of spectroscopic galaxies to improve the accuracy of the model prediction. We run the algorithm on similar to 11 960 deg(2) of imaging data from the Sloan Digital Sky Survey ( SDSS) Data Release 8 to construct a catalogue of 71 743 clusters in the redshift range 0.1 < z < 0.6 with richness after correcting for the incompleteness of the richness estimate greater than 20. We cross-match the cluster catalogue with external cluster catalogues to find that our photometric cluster redshift estimates are accurate with low bias and scatter, and that the corrected richness correlates well with X-ray luminosities and temperatures. We use the publicly available Canada-France-Hawaii Telescope Lensing Survey shear catalogue to calibrate the mass-richness relation from stacked weak lensing analysis. Stacked weak lensing signals are detected significantly for eight subsamples of the SDSS clusters divided by redshift and richness bins, which are then compared with model predictions including miscentring effects to constrain mean halo masses of individual bins. We find the richness correlates well with the halo mass, such that the corrected richness limit of 20 corresponds to the cluster virial mass limit of about 1 x 10(14) h(-1) M-circle dot for the SDSS DR8 cluster sample.

We forecast future constraints on local-type primordial non-Gaussianity parameter f(NL) with a photometric galaxy survey by Euclid, a continuum galaxy survey by Square Kilometre Array (SKA), and their combination. We derive a general expression for the covariance matrix of the power spectrum estimates of multiple tracers to show how the so-called multitracer technique improves constraints on f(NL). In particular we clarify the role of the overlap fraction of multiple tracers and the division method of the tracers. Our Fisher matrix analysis indicates that stringent constraints of sigma(f(NL)) less than or similar to 1 can be obtained even with a single survey, assuming five mass bins. When Euclid and SKA phase 1 (2) are combined, constraints on f(NL) are improved to sigma(f(NL)) = 0.61(0.50).

We present optical and near-IR imaging and spectroscopy of SGAS J105039.6+001730, a strongly lensed galaxy at z = 3.6252 magnified by >30x, and derive its physical properties. We measure a stellar mass of log(M-*/M-circle dot) = 9.5 +/- 0.35, star formation rates from [O II] lambda lambda 3727 and H beta of 55 +/- 25 and 84 +/- 24 M-circle dot yr(-1), respectively, an electron density of n(e) <= 10(3) cm(-2), an electron temperature of T-e <= 14,000 K, and a metallicity of 12 + log(O/H) = 8.3 +/- 0.1. The strong C III] lambda lambda 1907,1909 emission and abundance ratios of C, N, O, and Si are consistent with well-studied starbursts at z similar to 0 with similar metallicities. Strong P Cygni lines and He II lambda 1640 emission indicate a significant population of Wolf-Rayet stars, but synthetic spectra of individual populations of young, hot stars do not reproduce the observed integrated P Cygni absorption features. The rest-frame UV spectral features are indicative of a young starburst with high ionization, implying either (1) an ionization parameter significantly higher than suggested by rest-frame optical nebular lines, or (2) differences in one or both of the initial mass function and the properties of ionizing spectra of massive stars. We argue that the observed features are likely the result of a superposition of star forming regions with different physical properties. These results demonstrate the complexity of star formation on scales smaller than individual galaxies, and highlight the importance of systematic effects that result from smearing together the signatures of individual star forming regions within galaxies.

Context. At low redshift, a handful of gamma-ray bursts (GRBs) have been discovered with luminosities that are substantially lower (Liso ≲ 1048.5 erg s-1) than the average of more distant ones (Liso ≳ 1049.5 erg s-1). It has been suggested that the properties of several low-luminosity (low-L) GRBs are due to shock break-out, as opposed to the emission from ultrarelativistic jets. This has led to much debate about how the populations are connected. Aims. The burst at redshift z = 0.283 from 2012 April 22 is one of the very few examples of intermediate-L GRBs with a γ-ray luminosity of Liso ∼ 1049.6-49.9 erg s-1 that have been detected up to now. With the robust detection of its accompanying supernova SN 2012bz, it has the potential to answer important questions on the origin of low- and high-L GRBs and the GRB-SN connection. Methods. We carried out a spectroscopy campaign using medium- and low-resolution spectrographs with 6-10-m class telescopes, which covered a time span of 37.3 days, and a multi-wavelength imaging campaign, which ranged from radio to X-ray energies over a duration of ∼270 days. Furthermore, we used a tuneable filter that is centred at Hα to map star-formation in the host and the surrounding galaxies. We used these data to extract and model the properties of different radiation components and fitted the spectral energy distribution to extract the properties of the host galaxy. Results. Modelling the light curve and spectral energy distribution from the radio to the X-rays revealed that the blast wave expanded with an initial Lorentz factor of Γ0 ∼ 50, which is a low value in comparison to high-L GRBs, and that the afterglow had an exceptionally low peak luminosity density of ≲ 2 × 1030 erg s-1 Hz-1 in the sub-mm. Because of the weak afterglow component, we were able to recover the signature of a shock break-out in an event that was not a genuine low-L GRB for the first time. At 1.4 hr after the burst, the stellar envelope had a blackbody temperature of kBT ∼ 16 eV and a radius of ∼7 × 1013 cm (both in the observer frame). The accompanying SN 2012bz reached a peak luminosity of MV = -19.7 mag, which is 0.3 mag more luminous than SN 1998bw. The synthesised nickel mass of 0.58 M⊙, ejecta mass of 5.87 M⊙, and kinetic energy of 4.10 × 1052 erg were among the highest for GRB-SNe, which makes it the most luminous spectroscopically confirmed SN to date. Nebular emission lines at the GRB location were visible, which extend from the galaxy nucleus to the explosion site. The host and the explosion site had close-to-solar metallicity. The burst occurred in an isolated star-forming region with an SFR that is 1/10 of that in the galaxy's nucleus. Conclusions. While the prompt γ-ray emission points to a high-L GRB, the weak afterglow and the low Γ0 were very atypical for such a burst. Moreover, the detection of the shock break-out signature is a new quality for high-L GRBs. So far, shock break-outs were exclusively detected for low-L GRBs, while GRB 120422A had an intermediate Liso of ∼1049.6-49.9 erg s-1. Therefore, we conclude that GRB 120422A was a transition object between low- and high-L GRBs, which supports the failed-jet model that connects low-L GRBs that are driven by shock break-outs and high-L GRBs that are powered by ultra-relativistic jets. © 2014 ESO.

We study the weak lensing properties of filaments that connect clusters of galaxies through large cosmological N-body simulations. We select 4639 halo pairs with masses higher than 10(14) h(-1)M(circle dot) from the simulations and investigate dark matter distributions between two haloes with ray-tracing simulations. In order to classify filament candidates, we estimate convergence profiles and perform profile fitting. We find that matter distributions between haloes can be classified in a plane of fitting parameters, which allows us to select straight filaments from the ray-tracing simulations. We also investigate the statistical properties of these filaments, finding them to be consistent with previous studies. We find that 35 per cent of halo pairs possess straight filaments, 4 per cent of which can be detected directly at signal-to-noise ratio S/N >= 2 with weak lensing. Furthermore, we study the statistical properties of haloes at the edges of filaments. We find that haloes are preferentially elongated along filamentary structures and are less massive with increasing filament mass. However, the dependence of these halo properties on the masses of straight filaments is very weak.

We report the discovery of four doubly imaged quasar lenses. All the four systems are selected as lensed quasar candidates from the Sloan Digital Sky Survey data. We confirm their lensing hypothesis with additional imaging and spectroscopic follow-up observations. The discovered lenses are SDSS J0743+2457 with the source redshift z(s) = 2.165, the lens redshift z(l) = 0.381, and the image separation theta = 1.'' 034, SDSS J1128+2402 with z(s) = 1.608 and 0 = 0.'' 844, SDSS J1405+0959 with z(s) = 1.810, z(l) approximate to 0.66, and 0 = 1.'' 978, and SDSS J1515+1511 with z(s) = 2.054, z(l) = 0.742, and 0 = 1.'' 989. It is difficult to estimate the lens redshift of SDSS J1128+2402 from the current data. Two of the four systems (SDSS J1405+0959 and SDSS J1515+1511) are included in our final statistical lens sample to derive constraints on dark energy and the evolution of massive galaxies.

Weak lensing provides an important route toward collecting samples of clusters of galaxies selected by mass. Subtle systematic errors in image reduction can compromise the power of this technique. We use the B-mode signal to quantify this systematic error and to test methods for reducing this error. We show that two procedures are efficient in suppressing systematic error in the B-mode: (1) refinement of the mosaic CCD warping procedure to conform to absolute celestial coordinates and (2) truncation of the smoothing procedure on a scale of 10'. Application of these procedures reduces the systematic error to 20% of its original amplitude. We provide an analytic expression for the distribution of the highest peaks in noise maps that can be used to estimate the fraction of false peaks in the weak-lensing kappa-signal-to-noise ratio (S/N) maps as a function of the detection threshold. Based on this analysis, we select a threshold S/N=4.56 for identifying an uncontaminated set of weak-lensing peaks in two test fields covering a total area of similar to 3 deg(2). Taken together these fields contain seven peaks above the threshold. Among these, six are probable systems of galaxies and one is a superposition. We confirm the reliability of these peaks with dense redshift surveys, X-ray, and imaging observations. The systematic error reduction procedures we apply are general and can be applied to future large-area weak-lensing surveys. Our high-peak analysis suggests that with an S/N threshold of 4.5, there should be only 2.7 spurious weak-lensing peaks even in an area of 1000 deg2, where we expect similar to 2000 peaks based on our Subaru fields.

Objects of known brightness, like type la supernovae (SNIa), can be used to measure distances. If a massive object warps spacetime to form multiple images of a background SNIa, a direct test of cosmic expansion is also possible. However, these lensing events must first be distinguished from other rare phenomena. Recently, a supernova was found to shine much brighter than normal for its distance, which resulted in a debate: Was it a new type of superluminous supernova or a normal SNIa magnified by a hidden gravitational lens? Here, we report that a spectrum obtained after the supernova faded away shows the presence of a foreground galaxy-the first found to strongly magnify a SNIa. We discuss how more lensed SNIa can be found than previously predicted.

We derive the average mass profile of elliptical galaxies from the ensemble of 161 strong gravitational lens systems selected from several surveys, assuming that the mass profile scales with the stellar mass and effective radius of each lensing galaxy. The total mass profile is well fitted by a power law (r) proportional to r(gamma) with best-fitting slope gamma = -2.11 +/- 0.05. The decomposition of the total mass profile into stellar and dark matter distributions is difficult due to a fundamental degeneracy between the stellar initial mass function (IMF) and the dark matter fraction f(DM). We demonstrate that this IMF-f(DM) degeneracy can be broken by adding direct stellar mass fraction measurements by quasar microlensing observations. Our best-fitting model prefers the Salpeter IMF over the Chabrier IMF and a smaller central dark matter fraction than that predicted by adiabatic contraction models.

We present an analysis of the line-of-sight structure toward a sample of 10 strong lensing cluster cores. Structure is traced by groups that are identified spectroscopically in the redshift range, 0.1 <= z <= 0.9, and we measure the projected angular and comoving separations between each group and the primary strong lensing clusters in each corresponding line of sight. From these data we measure the distribution of projected angular separations between the primary strong lensing clusters and uncorrelated large-scale structure as traced by groups. We then compare the observed distribution of angular separations for our strong lensing selected lines of sight against the distribution of groups that is predicted for clusters lying along random lines of sight. There is clear evidence for an excess of structure along the line of sight at small angular separations (theta <= 6') along the strong lensing selected lines of sight, indicating that uncorrelated structure is a significant systematic that contributes to producing galaxy clusters with large cross sections for strong lensing. The prevalence of line-of-sight structure is one of several biases in strong lensing clusters that can potentially be folded into cosmological measurements using galaxy cluster samples. These results also have implications for current and future studies-such as the Hubble Space Telescope Frontier Fields-that make use of massive galaxy cluster lenses as precision cosmological telescopes; it is essential that the contribution of line-of-sight structure be carefully accounted for in the strong lens modeling of the cluster lenses.

We give an overview of complementarity and synergy in cosmology between the Square Kilometre Array and future survey projects in other wavelengths. In the SKA era, precision cosmology will be limited by systematic errors and cosmic variance, rather than statistical errors. However, combining and/or cross-correlating multi-wavelength data, from the SKA to the cosmic microwave background, optical/infrared and X-ray, substantially reduce these limiting factors. In this chapter, we summarize future survey projects and show highlights of complementarity and synergy, which can be very powerful to probe major cosmological problems such as dark energy, modified gravity and primordial non-Gaussianity.

Over the past few years two of the largest and highest fidelity experiments conceived have been approved for construction: Euclid is an ESA M-Class mission that will map three-quarters of the extra galactic sky with Hubble Space Telescope resolution optical and NIR imaging, and NIR spectroscopy, it has scientific aims (amongst others) are to create a map of the dark Universe and to determine the nature of dark energy. The Square Kilometre Array (SKA) has similar scientific aims (and others) using radio wavelength observations. The two experiments are synergistic in several respects, both through the scientific objectives and through the control of systematic effects. SKA1 and Euclid will be commissioned on similar timescales offering an exciting opportunity to exploit synergies between these facilities.

The baryon acoustic oscillation (BAO) measurement requires a sufficiently dense sampling of large-scale structure tracers with spectroscopic redshift, which is observationally expensive especially at high redshifts z greater than or similar to 1. Here we present an alternative route of the BAO analysis that uses the cross-correlation of sparse spectroscopic tracers with a much denser photometric sample, where the spectroscopic tracers can be quasars or bright, rare galaxies that are easier to access spectroscopically. We show that measurements of the cross-correlation as a function of the transverse comoving separation rather than the angular separation avoid a smearing of the BAO feature without mixing the different scales at different redshifts in the projection, even for a wide redshift slice delta z similar or equal to 1. The bias, scatter and catastrophic redshift errors of the photometric sample affect only the overall normalization of the cross-correlation which can be marginalized over when constraining the angular diameter distance. As a specific example, we forecast the expected accuracy of the BAO geometrical test via the cross-correlation of the Sloan Digital Sky Survey (SDSS) and Baryon Oscillation Spectroscopic Survey (BOSS) spectroscopic quasar sample with a dense photometric galaxy sample that is assumed to have a full overlap with the SDSS/BOSS survey region. We show that this cross-correlation BAO analysis allows us to measure the angular diameter distances to a fractional accuracy of about 10 per cent at each redshift bin over 1 less than or similar to z less than or similar to 3, if the photometric redshift errors of the galaxies, Sigma(z)/(1 + z), are better than 10-20 per cent level.

We study the prospects for measuring the dark matter distribution of voids with stacked weak lensing. We select voids from a large set of N-body simulations and explore their lensing signals with the full ray-tracing simulations including the effect of the large-scale structure along the line of sight. The lensing signals are compared with simple void model predictions to infer the three-dimensional mass distribution of voids. We show that the stacked weak lensing signals are detected at a significant level (S/N >= 5) for a 5000 degree(2) survey area, for a wide range of void radii up to similar to 50 Mpc. The error from the galaxy shape noise little affects lensing signals at large scale. It is also found that dense ridges around voids have a great impact on the weak lensing signals, suggesting that proper modelling of the void density profile including surrounding ridges is essential for extracting the average total underdense mass of voids.

Recently, Chornock and co-workers announced the Pan-STARRS discovery of a transient source reaching an apparent peak luminosity of similar to 4 x 10(44) erg s(-1). We show that the spectra of this transient source are well fit by normal Type Ia supernova (SNIa) templates. The multi-band colors and light-curve shapes are also consistent with normal SNeIa at the spectroscopically determined redshift of z = 1.3883; however, the observed flux is a constant factor of similar to 30 times too bright in each band over time as compared to the templates. At minimum, this shows that the peak luminosities inferred from the light-curve widths of some SNeIa will deviate significantly from the established, empirical relation used by cosmologists. We argue on physical grounds that the observed fluxes do not reflect an intrinsically luminous SNIa, but rather PS1-10afx is a normal SNIa whose flux has been magnified by an external source. The only known astrophysical source capable of such magnification is a gravitational lens. Given the lack of obvious lens candidates, such as galaxy clusters, in the vicinity, we further argue that the lens is a supermassive black hole or a comparatively low-mass dark matter halo. In this case, the lens continues to magnify the underlying host galaxy light. If confirmed, this discovery could impact a broad range of topics including cosmology, gamma-ray bursts, and dark matter halos.

We present a Subaru weak lensing measurement of ACT-CL J0022.2-0036, one of the most luminous, high-redshift (z = 0.81) Sunyaev-Zel'dovich (SZ) clusters discovered in the 268 deg(2) equatorial region survey of the Atacama Cosmology Telescope that overlaps with Sloan Digital Sky Survey (SDSS) Stripe 82 field. Ours is the first weak lensing study with Subaru at such high redshifts. For the weak lensing analysis using i'-band images, we use a model-fitting (Gauss-Laguerre shapelet) method to measure shapes of galaxy images, where we fit galaxy images in different exposures simultaneously to obtain best-fitting ellipticities taking into account the different point spread functions (PSFs) in each exposure. We also take into account the astrometric distortion effect on galaxy images by performing the model fitting in the world coordinate system. To select background galaxies behind the cluster at z = 0.81, we use photometric redshift estimates for every galaxy derived from the co-added images of multi-passband Br'i'z'Y, with PSF matching/homogenization. After a photometric redshift cut for background galaxy selection, we detect the tangential weak lensing distortion signal with a total signal-to-noise ratio of about 3.7. By fitting a Navarro-Frenk-White model to the measured shear profile, we find the cluster mass to be M-200 (rho) over barm = [7.5(-2.8)(+3.2)(stat.)(+1.3)(-0.6)(sys.)] x 10(14) M-circle dot h(-1). The weak lensing-derived mass is consistent with previous mass estimates based on the SZ observation, with assumptions of hydrostatic equilibrium and virial theorem, as well as with scaling relations between SZ signal and mass derived from weak lensing, X-ray and velocity dispersion, within the measurement errors. We also show that the existence of ACT-CL J0022.2-0036 at z = 0.81 is consistent with the cluster abundance prediction of the Lambda-dominated cold dark matter structure formation model. We thus demonstrate the capability of Subaru-type ground-based images for studying weak lensing of high-redshift clusters.

We report the discovery of a pair of quasars at z = 1.487, with a separation of 8 ''.585 +/- 0 ''.002. Subaru Telescope infrared imaging reveals the presence of an elliptical and a disk-like galaxy located almost symmetrically between the quasars, in a cross-like configuration. Based on absorption lines in the quasar spectra and the colors of the galaxies, we estimate that both galaxies are located at redshift z = 0.899. This, as well as the similarity of the quasar spectra, suggests that the system is a single quasar multiply imaged by a galaxy group or cluster acting as a gravitational lens, although the possibility of a binary quasar cannot be fully excluded. We show that the gravitational lensing hypothesis implies that these galaxies are not isolated, but must be embedded in a dark matter halo of virial mass similar to 4 x 10(14) h(70)(-1) M-circle dot assuming a Navarro-Frenk-White model with a concentration parameter of c(vir) = 6, or a singular isothermal sphere profile with a velocity dispersion of similar to 670 km s(-1). We place constraints on the location of the dark matter halo, as well as the velocity dispersions of the galaxies. In addition, we discuss the influence of differential reddening, microlensing, and intrinsic variability on the quasar spectra and broadband photometry.

We present 279 epochs of optical monitoring data spanning 5.4 years from 2007 January to 2012 June for the largest image separation (22.'' 6) gravitationally lensed quasar, SDSS J1029+2623. We find that image A leads the images B and C by Delta t(AB) = (744 +/- 10) days (90% confidence); the uncertainty includes both statistical uncertainties and systematic differences due to the choice of models. With only a similar to 1% fractional error, the interpretation of the delay is limited primarily by cosmic variance due to fluctuations in the mean line-of-sight density. We cannot separate the fainter image C from image B, but since image C trails image B by only 2-3 days in all models, the estimate of the time delay between images A and B is little affected by combining the fluxes of images B and C. There is weak evidence for a low level of microlensing, perhaps created by the small galaxy responsible for the flux ratio anomaly in this system. Interpreting the delay depends on better constraining the shape of the gravitational potential using the lensed host galaxy, other lensed arcs, and the structure of the X-ray emission.

We study the origin of absorption features on the blue side of the C IV broad emission line of the large-separation lensed quasar SDSS J1029+2623 at z(em) similar to 2.197. The quasar images, produced by a foreground cluster of galaxies, have a maximum separation angle of theta similar to 22 ''.5. The large angular separation suggests that the sight lines to the quasar central source can go through different regions of outflowing winds from the accretion disk of the quasar, providing a unique opportunity to study the structure of outflows from the accretion disk, a key ingredient for the evolution of quasars as well as for galaxy formation and evolution. Based on medium- and high-resolution spectroscopy of the two brightest images conducted at the Subaru telescope, we find that each image has different intrinsic levels of absorptions, which can be attributed either to variability of absorption features over the time delay between the lensed images, Delta t similar to 744 days, or to the fine structure of quasar outflows probed by the multiple sight lines toward the quasar. While both these scenarios are consistent with the current data, we argue that they can be distinguished with additional spectroscopic monitoring observations.

We present Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) observations of SDSS J1029+2623, a three-image quasar lens system produced by a foreground cluster at z = 0.584. Our strong lensing analysis reveals six additional multiply imaged galaxies in addition to the multiply imaged quasar. We confirm the complex nature of the mass distribution of the lensing cluster, with a bimodal dark matter distribution which deviates from the Chandra X-ray surface brightness distribution. The Einstein radius of the lensing cluster is estimated to be theta(E) = 15.2 +/- 0.5 arcsec for the quasar redshift of z = 2.197. We derive a radial mass distribution from the combination of strong lensing, HST/ACS weak lensing and Subaru/Suprime-cam weak lensing analysis results, finding a best-fitting virial mass of M-vir = 1.55(-0.35)(+0.40) x 10(14) h(-1) M-circle dot and a concentration parameter of c(vir) = 25.7(-7.5)(+14.1). The lensing mass estimate at the outer radius is smaller than the X-ray mass estimate by a factor of similar to 2. We ascribe this large mass discrepancy to shock heating of the intracluster gas during a merger, which is also suggested by the complex mass and gas distributions and the high value of the concentration parameter. In the HST image, we also identify a probable galaxy, GX, in the vicinity of the faintest quasar image C. In strong lens models, the inclusion of GX explains the anomalous flux ratios between the quasar images. The morphology of the highly elongated quasar host galaxy is also well reproduced. The best-fitting model suggests large total magnifications of 30 for the quasar and 35 for the quasar host galaxy, and has an AB time delay consistent with the measured value.

Based on a suite of state-of-the-art high-resolution N-body simulations, we revisit the so-called halofit model as an accurate fitting formula for the nonlinear matter power spectrum. While the halofit model has frequently been used as a standard cosmological tool to predict the nonlinear matter power spectrum in a universe dominated by cold dark matter, its precision has been limited by the low resolution of N-body simulations used to determine the fitting parameters, suggesting the necessity of an improved fitting formula at small scales for future cosmological studies. We run high-resolution N-body simulations for 16 cosmological models around the Wilkinson Microwave Anisotropy Probe best-fit cosmological parameters (one-, three-, five-, and seven-year results), including dark energy models with a constant equation of state. The simulation results are used to re-calibrate the fitting parameters of the halofit model so as to reproduce small-scale power spectra of the N-body simulations, while keeping the precision at large scales. The revised fitting formula provides an accurate prediction of the nonlinear matter power spectrum in a wide range of wavenumbers (k <= 30 h Mpc(-1)) at redshifts 0 <= z <= 10, with 5% precision for k <= 1 h Mpc(-1) at 0 <= z <= 10 and 10% for 1 <= k <= 10 h Mpc(-1) at 0 <= z <= 3. We discuss the impact of the improved halofit model on weak-lensing power spectra and correlation functions, and show that the improved model better reproduces ray-tracing simulation results.