Huang, Chih-Wei Locutus, Wu, Jiun-Huei Proty, Ho, Paul T. P., Koch, Patrick M., Liao, Yu-Wei, Lin, Kai-Yang, ...
We investigate the scaling relations between the X-ray and the thermal Sunyaev-Zel'dovich Effect (SZE) properties of clusters of galaxies, using data taken during 2007 by the Y.T. Lee Array for...
Platform Deformation Refined Pointing and Phase Correction for the AMiBA Hexapod Telescope (2009)
Koch, Patrick M., Kesteven, Michael, Chang, Yu-Yen, Huang, Yau-De, Raffin, Philippe, Chen, Ke-Yung, ...
The Array for Microwave Background Anisotropy (AMiBA) is a radio interferometer for research in cosmology, currently operating 7 0.6m diameter antennas co-mounted on a 6m diameter platform driven by...
Lemze, Doron, Broadhurst, Tom, Rephaeli, Yoel, Barkana, Rennan, Umetsu, Keiichi
We examine the dynamics structure of the rich cluster A1689, combining VLT/VIMOS spectroscopy with Subaru/Suprime-Cam imaging. The radial velocity distribution of ~500 cluster members is bounded by a...
Umetsu, Keiichi, Medezinski, Elinor, Broadhurst, Tom, Zitrin, Adi, Okabe, Nobuhiro, Hsieh, Bau-Ching, ...
We derive an accurate mass distribution of the rich galaxy cluster Cl0024+1654 (z=0.395) based on deep Subaru BR_{c}z' imaging and our recent comprehensive strong lensing analysis of HST/ACS/NIC3...
Medezinski, Elinor, Broadhurst, Tom, Umetsu, Keiichi, Oguri, Masamune, Rephaeli, Yoel, Benítez, Narciso
We carefully examine the luminous content of three high mass clusters, A1703 (z=0.258), A370 (z=0.375) and RXJ1347-11 (z=0.45), with deep Subaru imaging. Accurate three-colour data allows us to...
LoCuSS: Subaru Weak Lensing Study of 30 Galaxy Clusters (2009)
Okabe, Nobuhiro, Takada, Masahiro, Umetsu, Keiichi, Futamase, Toshifumi, Smith, Graham P.
(Abridged) We use Subaru data to conduct a detailed weak-lensing study of the dark matter distribution in a sample of 30 X-ray luminous galaxy clusters at 0.15
Zitrin, Adi, Broadhurst, Tom, Umetsu, Keiichi, Coe, Dan, Benítez, Narciso, Ascaso, Begoña, ...
We present an improved strong-lensing analysis of Cl0024+1654 ($z$=0.39) using deep HST/ACS/NIC3 images, based on 33 multiply-lensed images of 11 background galaxies. These are found with a model...
AMiBA: Broadband Heterodyne CMB Interferometry (2009)
Chen, Ming-Tang, Li, Chao-Te, Hwang, Yuh-Jing, Jiang, Homin, Altamirano, Pablo, Chang, Chia-Hao, ...
The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first science results on the detection of galaxy clusters via the Sunyaev Zel'dovich effect. The science objectives required...
AMiBA: System Performance (2009)
Lin, Kai-Yang, Li, Chao-Te, Ho, Paul T. P., Huang, Chih-Wei Locutus, Liao, Yu-Wei, Liu, Guo-Chin, ...
The Y.T. Lee Array for Microwave Background Anisotropy (AMiBA) started scientific operation in early 2007. This work describes the optimization of the system performance for the measurements of the...
The AMiBA Hexapod Telescope Mount (2009)
Koch, Patrick M., Kesteven, Michael, Nishioka, Hiroaki, Jiang, Homin, Lin, Kai-Yang, Umetsu, Keiichi, ...
AMiBA is the largest hexapod astronomical telescope in current operation. We present a description of this novel hexapod mount with its main mechanical components -- the support cone, universal...
Keiichi Umetsu, Mark Birkinshaw, Guo-chin Liu, Elinor Medezinski, Tom Broadhurst, ...
We present a multiwavelength analysis of a sample of four hot (TX> 8keV) X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA Sunyaev-Zel’dovich effect (SZE) and Subaru weak...
Tests of AMiBA Data Integrity (2008)
Nishioka, Hiroaki, Wang, Fu-Cheng, Wu, Jiun-Huei Proty, Ho, Paul T. P., Huang, Chih-Wei Locutus, Koch, Patrick M., ...
We describe methods used to validate data from the Y.T. Lee Array for Microwave Background Anisotropy (AMiBA), an interferometric array designed to measure the Sunyaev-Zel'dovich effect and the...
Lemze, Doron, Broadhurst, Tom, Rephaeli, Yoel, Barkana, Rennan, Umetsu, Keiichi
We examine the internal dynamics and caustic structure of the rich cluster A1689, combining VLT/VIMOS spectroscopy with Subaru/Suprime-Cam imaging. The radial velocity distribution of $\sim 500$...
The Yuan-Tseh Lee Array for Microwave Background Anisotropy (2008)
Ho, Paul T. P., Altamirano, Pablo, Chang, Chia-Hao, Chang, Shu-Hao, Chang, Su-Wei, Chen, Chung-Cheng, ...
The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the first interferometer dedicated to studying the cosmic microwave background (CMB) radiation at 3mm wavelength. The choice of...
Umetsu, Keiichi, Birkinshaw, Mark, Liu, Guo-Chin, Wu, Jiun-Huei Proty, Medezinski, Elinor, Broadhurst, Tom, ...
We present a multiwavelength analysis of a sample of four hot (T_X>8keV) X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA Sunyaev-Zel'dovich effect (SZE) and Subaru weak...
Comparison of Cluster Lensing Profiles with Lambda CDM Predictions (2008)
Broadhurst, Tom, Umetsu, Keiichi, Medezinski, Elinor, Oguri, Masamune, Rephaeli, Yoel
We derive lens distortion and magnification profiles of four well known clusters observed with Subaru. Each cluster is very well fitted by the general form predicted for Cold Dark Matter (CDM)...
Combining Lens Distortion and Depletion to Map the Mass Distribution of A1689 (2007)
Umetsu, Keiichi, Broadhurst, Tom
[Abridged] We derive a projected 2D mass map of the well studied galaxy cluster A1689 based on an entropy-regularized maximum-likelihood combination of the lens magnification and distortion of red...
A Method for Weak Lensing Flexion Analysis by the HOLICs Moment Approach (2007)
Okura, Yuki, Umetsu, Keiichi, Futamase, Toshifumi
We have developed a method for measuring higher-order weak lensing distortions of faint background galaxies, namely the weak gravitational flexion, by fully extending the Kaiser, Squires & Broadhurst...
Subaru Weak Lensing Study of Seven Merging Clusters: Distributions of Mass and Baryons (2007)
Okabe, Nobuhiro, Umetsu, Keiichi
We present and compare projected distributions of mass, galaxies, and the intracluster medium (ICM) for a sample of merging clusters of galaxies based on the joint weak-lensing, optical photometric,...
Observational Constraints on the ICM Temperature Enhancement by Cluster Mergers (2007)
Okabe, Nobuhiro, Umetsu, Keiichi
We present results from a combined weak lensing and X-ray analysis of the merging cluster A1914 at a redshift of $z=0.1712$ based on $R_{\rm}$-band imaging data with Subaru/Suprime-Cam and archival...
Probing the Cluster Mass Distribution using Subaru Weak Lensing Data (2007)
Umetsu, Keiichi, Takada, Masahiro, Broadhurst, Tom
We present results from a weak lensing analysis of the galaxy cluster A1689 (z=0.183) based on deep wide-field imaging data taken with Suprime-Cam on Subaru telescope. A maximum entropy method has...
Using Weak Lensing Dilution to Improve Measurements of the Luminous and Dark Matter in A1689 (2006)
Medezinski, Elinor, Broadhurst, Tom, Umetsu, Keiichi, Coe, Dan, Benitez, Narciso, Ford, Holland, ...
The E/SO sequence of a cluster defines a boundary redward of which a reliable weak lensing signal can be obtained from background galaxies, uncontaminated by cluster members. For bluer colors, both...
How Well Can Weak Lensing Measure the Mass of Galaxy Clusters? (2006)
Wu, Jun-Mein, Umetsu, Keiichi, Chien, Chia-Hung, Chiueh, Tzihong
The technique of weak-lensing aperture mass densitometry, so called the zeta-statistic, has recently been popular in actual observations for measurement of individual cluster mass. It has however...
A New Measure for Weak Lensing Flexion (2006)
Okura, Yuki, Umetsu, Keiichi, Futamase, Toshifumi
We study a possibility to use the octopole moment of gravitationally lensed images as a direct measure of the third-order weak gravitational lensing effect, or the gravitational flexion. It turns out...
Discovery of a Strongly Lensed Galaxy at z=3.9 behind a z=0.83 Galaxy Cluster (2005)
Umetsu, Keiichi, Tanaka, Masayuki, Kodama, Tadayuki, Tanaka, Ichi, Futamase, Toshifumi, Kashikawa, Nobunari, ...
We report the discovery and spectroscopic confirmation of three gravitationally-lensed images of a galaxy at z=3.9 in the background of a distant, rich cluster of galaxies at z=0.83, on the basis of...
The Build-up of the Colour-Magnitude Relation as a Function of Environment (2005)
Tanaka, Masayuki, Kodama, Tadayuki, Arimoto, Nobuo, Okamura, Sadanori, Umetsu, Keiichi, Shimasaku, Kazuhiro, ...
We discuss the environmental dependence of galaxy evolution based on deep panoramic imaging of two distant clusters taken with Suprime-Cam as part of the PISCES project. By combining with the SDSS...
Cluster Baryon Fraction and Structure from the Convergence/SZ Effect Diagram (2005)
Umetsu, Keiichi, Wu, Jun-Mein, Chiueh, Tzihong, Birkinshaw, Mark
The cross-correlation of Sunyaev-Zel'dovich effect (SZ) and weak-lensing imaging surveys can be used to test how well hot baryons trace dark matter in clusters of galaxies. We examine this concept...
Can the Steep Mass Profile of A1689 Be Explained by a Triaxial Dark Halo? (2005)
Oguri, Masamune, Takada, Masahiro, Umetsu, Keiichi, Broadhurst, Tom
The steep mass profile of A1689 derived from recent detailed lensing observations is not readily reconciled with the low concentration halos predicted by the standard CDM model. However, halo...
The Surprisingly Steep Mass Profile of Abell 1689, from a Lensing Analysis of Subaru Images (2004)
Broadhurst, Tom, Takada, Masahiro, Umetsu, Keiichi, Kong, Xu, Arimoto, Nobuo, Chiba, Masashi, ...
Subaru observations of A1689 (z=0.183) are used to derive an accurate, model-independent mass profile for the entire cluster, r
Simulation of a Combined SZE and Weak Lensing Cluster Survey for AMiBA Experiment (2004)
Umetsu, Keiichi, Chiueh, Tzihong, Lin, Kai-Yang, Wu, Jun-Mein, Tseng, Yao-Huan
We present simulations of interferometric Sunyaev-Zel'dovich effect (SZE) and optical weak lenisng observations for the forthcoming AMiBA experiment, aiming at searching for high-redshift clusters of...
The topology of weak lensing field in the neighborhood of MS1054-03 (2002)
Sato, Jun'ichi, Umetsu, Keiichi, Futamase, Toshifumi, Yamada, Toru
We report the first measurement of genus curves for the two-dimensional mass map in the neighborhood of rich, X-ray luminous galaxy cluster MS1054-03 at z=0.83, reconstructed from weak lensing data...
Observational Strategies of CMB Temperature and Polarization Interferometry Experiments (2002)
Park, Chan-Gyung, Ng, Kin-Wang, Park, Changbom, Liu, Guo-Chin, Umetsu, Keiichi
We have simulated the interferometric observation of the Cosmic Microwave Background (CMB) temperature and polarization fluctuations. We have constructed data pipelines from the time-ordered raw...
Cluster Mass Reconstruction by a Weak Shear Field (2000)
Umetsu, Keiichi, Tada, Masashi, Futamase, Toshifumi
The tidal gravitational field of galaxy clusters causes a coherent distortion of the images of background sources. Since the distribution of image distortions, namely the shear field, traces the...
Umetsu, Keiichi, Futamase, Toshifumi
We present a weak-lensing analysis of a region around the galaxy cluster Cl 1604+4304 (z=0.897) on the basis of the deep observations with the HST/WFPC2. We apply a variant of Schneider's aperture...
Hattori, Makoto, Umetsu, Keiichi
We have shown that there exists low-frequency growing modes driven by a global temperature gradient in electron and ion plasmas, by linear perturbation analysis within the frame work of plasma...