Adiabatic versus Isocurvature Non--Gaussianity (2009)
Hikage, Chiaki, Munshi, Dipak, Heavens, Alan, Coles, Peter
We study the extent to which one can distinguish primordial non--Gaussianity (NG) arising from adiabatic and isocurvature perturbations. We make a joint analysis of different NG models based on...
Limits on Isocurvature Perturbations from Non-Gaussianity in WMAP Temperature Anisotropy (2008)
Hikage, Chiaki, Koyama, Kazuya, Matsubara, Takahiko, Takahashi, Tomo, Yamaguchi, Masahide
We study the effect of primordial isocurvature perturbations on non-Gaussian properties in CMB temperature anisotropies. We consider generic forms of the non-linearity of isocurvature perturbations...
Hikage, Chiaki, Matsubara, Takahiko, Coles, Peter, Liguori, Michele, Hansen, Frode K., Matarrese, Sabino
We present an analysis of the Minkowski Functionals (MFs) describing the WMAP three-year temperature maps to place limits on possible levels of primordial non-Gaussianity. In particular, we apply...
The Effect of Primordial Non--Gaussianity on the Topology of Large-Scale Structure (2007)
Hikage, Chiaki, Coles, Peter, Grossi, Margherita, Moscardini, Lauro, Dolag, Klaus, Branchini, Enzo, ...
We study the effect of primordial non--Gaussianity on the development of large-scale cosmic structure using high-resolution N-body simulations. In particular, we focus on the topological properties...
Large-Scale Anisotropic Correlation Function of SDSS Luminous Red Galaxies (2007)
Okumura, Teppei, Matsubara, Takahiko, Eisenstein, Daniel J., Kayo, Issha, Hikage, Chiaki, Szalay, Alexander S., ...
We study the large-scale anisotropic two-point correlation function using 46,760 luminous red galaxies at redshifts 0.16 -- 0.47 from the Sloan Digital Sky Survey. We measure the correlation function...
Shirata, Akihito, Suto, Yasushi, Hikage, Chiaki, Shiromizu, Tetsuya, Yoshida, Naoki
We explore observational constraints on possible deviations from Newtonian gravity by means of large-scale clustering of galaxies. We measure the power spectrum and the bispectrum of Sloan Digital...
Nishimichi, Takahiro, Kayo, Issha, Hikage, Chiaki, Yahata, Kazuhiro, Taruya, Atsushi, Jing, Yi Peng, ...
Nishimichi, Takahiro, Kayo, Issha, Hikage, Chiaki, Yahata, Kazuhiro, Taruya, Atsushi, Jing, Y. P., ...
We consider nonlinear biasing models of galaxies with particular attention to a correlation between linear and quadratic biasing coefficients, b_1 and b_2. We first derive perturbative expressions...
Hikage, Chiaki, Komatsu, Eiichiro, Matsubara, Takahiko
We derive analytical formulae for the Minkowski Functions of the cosmic microwave background (CMB) and large-scale structure (LSS) from primordial non-Gaussianity. These formulae enable us to...
Topology Analysis of the Sloan Digital Sky Survey: I. Scale and Luminosity Dependences (2005)
Park, Changbom, Choi, Yun-Young, Vogeley, Michael, Gott III, J. Richard, Kim, Juhan, Hikage, Chiaki, ...
We measure the topology of volume-limited galaxy samples selected from a parent sample of 314,050 galaxies in the Sloan Digital Sky Survey(SDSS), which is now complete enough to describe the fully...
Fourier Phase Analysis of SDSS Galaxies (2005)
Hikage, Chiaki, Matsubara, Takahiko, Suto, Yasushi, Park, Changbom, Szalay, Alexander S., Brinkmann, Jon
We present a first analysis of the clustering of SDSS galaxies using the distribution function of the sum of Fourier phases. This statistic was recently proposed by one of authors as a new method to...
Hikage, Chiaki, Matsubara, Takahiko, Suto, Yasushi
We explore a signature of phase correlations in Fourier modes of dark matter density fields induced by nonlinear gravitational clustering. We compute the distribution function of the phase sum of the...
Minkowski Functionals of SDSS galaxies I : Analysis of Excursion Sets (2003)
Hikage, Chiaki, Schmalzing, Jens, Buchert, Thomas, Suto, Yasushi, Kayo, Issha, Taruya, Atsushi, ...
We present a first morphometric investigation of a preliminary sample from the SDSS of 154287 galaxies with apparent magnitude 14.5
Biasing and Genus Statistics of Dark Matter Halos in the Hubble Volume Simulation (2003)
Hikage, Chiaki, Taruya, Atsushi, Suto, Yasushi
We present a numerical analysis of genus statistics for dark matter halo catalogs from the Hubble volume simulation. The huge box-size of the Hubble volume simulation enables us to carry out a...
Minkowski Functionals of SDSS galaxies I: Analysis of Excursion Sets (2003)
Chiaki Hikage, Jens Schmalzing, Thomas Buchert, Yasushi Suto, Issha Kayo, Atsushi Taruya, ...
We present a rst morphometric investigation of a preliminary sample from the SDSS of 154287 galaxies with apparent magnitude 14:5 < m r < 17:5 and redshift 0:001 < z < 0:4. We measure the...
Three-Dimensional Genus Statistics of Galaxies in the SDSS Early Data Release (2002)
Hikage, Chiaki, Suto, Yasushi, Kayo, Issha, Taruya, Atsushi, Matsubara, Takahiko, Vogeley, Michael S., ...
We present the first analysis of three-dimensional genus statistics for the SDSS EDR galaxy sample. Due to the complicated survey volume and the selection function, analytic predictions of the genus...
Genus statistics for galaxy clusters and nonlinear biasing of dark matter halos (2001)
Hikage, Chiaki, Taruya, Atsushi, Suto, Yasushi
We derive an analytic formula of genus for dark matter halos assuming that the primordial mass density field obeys the random-Gaussian statistics. In particular, we for the first time take account of...