Toshifumi Futamase

LoCuSS: Subaru Weak Lensing Study of 30 Galaxy Clusters

(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<z<0.3. A weak-lensing signal is detected at high statistical significance in each cluster, the total detection S/N ranging from 5 to 13. In this paper we concentrate on fitting spherical models to the tangential distortion profiles of the clusters. When the models are fitted to the clusters individually, we are unable to discriminate statistically between SIS and NFW models. However when the tangential distortion profiles of the individual clusters are combined, and models fitted to the stacked profile, the SIS model is rejected at 6- and 11-sigma, respectively, for low- and high-mass bins. We also use the individual cluster NFW model fits to investigate the relationship between cluster mass (M_vir) and concentration (c_vir), finding an anti-correlation of c_vir and M_vir. The best-fit c_vir-M_vir relation is: c_vir(M_vir) propto M_vir^{-alpha} with alpha=0.41+/-0.19 -- i.e. a non-zero slope is detected at 2sigma significance. We then investigate the optimal radius within which to measure cluster mass, finding that the typical fractional errors are improved to sigma(M_Delta)/M_Delta ~ 0.1-0.2 for cluster masses at higher over-densities Delta=500-2000, from 0.2-0.3 for the virial over-density (~110). Further comparisons between mass measurements based on spherical model fitting and the model-independent aperture mass method reveal that the 2D aperture mass enclosed within a cylinder of a given aperture radius is systematically greater than the 3D spherical mass obtained from NFW model fitting: M_2D/M_3D= 1.34 and 1.40 for Delta=500 and 110, respectively. The amplitude of this effect agrees well with that predicted by integrating the NFW model along the line-of-sight.

Complete constraints on a nonminimally coupled chaotic inflationary scenario from the cosmic microwave background

Astronomical Institute, Graduate School of Science, Tohoku University, Sendai 980-8578, JapanWe present complete constraints imposed from observations of the cosmic microwave backgroundradiation (CMBR) on the chaotic inflationary scenario with a nonminimally coupled inflaton fieldproposed by Fakir and Unruh (FU). Our constraints are complete in the sense that we investigateboth the scalar density perturbation and the tensor gravitational wave in the Jordan frame, as wellas in the Einstein frame. This makes the constraints extremely strong without any ambiguities dueto the choice of frames. We find that the FU scenario generates tiny tensor contributions to theCMBR relative to chaotic models in minimal coupling theory, in spite of its spectral index of scalarperturbation being slightly tilted. This means that the FU scenario will be excluded if any tensorcontributions to CMBR are detected by the forthcoming satellite missions. Conversely, if no tensornature is detected despite the tilted spectrum, a minimal chaotic scenario will be hard to explainand the FU scenario will be supported.PACS number(s): 04.50.+h, 98.70.Vc, 98.80.CqI. INTRODUCTION

LoCuSS: THE MASS DENSITY PROFILE OF MASSIVE GALAXY CLUSTERS AT z = 0.2* , **

We present a stacked weak-lensing analysis of an approximately mass-selected sample of 50 galaxy clusters at 0.15 < z < 0.3, based on observations with Suprime-Cam on the Subaru Telescope. We develop a new method for selecting lensed background galaxies from which we estimate that our sample of red background galaxies suffers just 1% contamination. We detect the stacked tangential shear signal from the full sample of 50 clusters, based on this red sample of background galaxies, at a total signal-to-noise ratio of 32.7. The Navarro-Frenk-White model is an excellent fit to the data, yielding sub-10% statistical precision on mass and concentration: , (). Tests of a range of possible systematic errors, including shear calibration and stacking-related issues, indicate that they are subdominant to the statistical errors. The concentration parameter obtained from stacking our approximately mass-selected cluster sample is broadly in line with theoretical predictions. Moreover, the uncertainty on our measurement is comparable with the differences between the different predictions in the literature. Overall, our results highlight the potential for stacked weak-lensing methods to probe the mean mass density profile of cluster-scale dark matter halos with upcoming surveys, including Hyper-Suprime-Cam, Dark Energy Survey, and KIDS.

LoCuSS: calibrating mass-observable scaling relations for cluster cosmology with Subaru weak-lensing observations

N.O., M.T., and T.F. are supported in part by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (N.O.: 20740099; M.T.: 20740119; T.F.: 20540245). Y.-Y.Z. and N.O. acknowledge support by the DFG through the Emmy Noether Research Grant RE 1462/2, through Schwerpunkt Program 1177, and through project B6 “Gravitational Lensing and X-ray Emission by Non-Linear Structures” of Transregional Collaborative Research Centre TRR 33 “The Dark Universe,” and support by the German BMBF through the Verbundforschung under grants 50 OR 0601 and 50 OR 1005. A.F. acknowledges support from BMBF/DLR under grant 50 OR 0207 and MPG. A.F. was partially supported by NASA grant NNX08AX46G to UMBC. K.U. is partially supported by the National Science Council of Taiwan under the grant NSC95-2112-M-001-074-MY2. G.P.S. acknowledges support from the Royal Society. This work is supported by a Grant-in-Aid for the COE Program “Exploring NewScience by Bridging Particle–MatterHierarchy” and theGCOE Program “Weaving Science Web beyond Particle–Matter Hierarchy” in Tohoku University, funded by the Ministry of Education, Science, Sports and Culture of Japan. This work is in part supported by a Grant-in-Aid for Science Research in a Priority Area “Probing the Dark Energy through an Extremely Wide and Deep Survey with Subaru Telescope” (18072001) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. Y.-Y.Z. and A.F. acknowledge the hospitality of the Tohoku University during their frequent visits. This work is supported in part by the World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan.

Cosmology with high-redshift galaxy survey: Neutrino mass and inflation

High-

The Post-Newtonian Approximation for Relativistic Compact Binaries

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New derivation of a third post-Newtonian equation of motion for relativistic compact binaries without ambiguity

galaxy redshift surveys open up exciting possibilities for precision determinations of neutrino masses and inflationary models. The high-

SUBARU WEAK-LENSING SURVEY OF DARK MATTER SUBHALOS IN THE COMA CLUSTER: SUBHALO MASS FUNCTION AND STATISTICAL PROPERTIES*

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LoCuSS: Testing hydrostatic equilibrium in galaxy clusters

surveys are more useful for cosmology than low-

Weak Lensing Mass Measurements of Substructures in COMA Cluster with Subaru/Suprime-Cam

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