Formation of globular clusters induced by external ultraviolet radiation (2009)
Hasegawa, Kenji, Umemura, Masayuki, Kitayama, Tetsu
We present a novel scenario for globular cluster (GC) formation, where the ultraviolet (UV) background radiation effectively works so as to produce compact star clusters. Here, we explore the...
Constraints on the intracluster dust emission in the coma cluster of galaxies (2009)
Kitayama, Tetsu, Ito, Yuichi, Okada, Yoko, Kaneda, Hidehiro, Takahashi, Hidenori, Ota, Naomi, ...
Kawahara, Hajime, Reese, Erik D., Kitayama, Tetsu, Sasaki, Shin, Suto, Yasushi
Our previous analysis indicates that small-scale fluctuations in the intracluster medium (ICM) from cosmological hydrodynamic simulations follow the lognormal distribution. In order to test the...
Lx-T relation and thermal evolution of galaxy clusters (2008)
Ota, Naomi, Kitayama, Tetsu, Masai, Kuniaki, Mitsuda, Kazuhisa
Systematic Errors in the Hubble Constant Measurement from the Sunyaev-Zel'dovich effect (2007)
Kawahara, Hajime, Kitayama, Tetsu, Sasaki, Shin, Suto, Yasushi
The Hubble constant estimated from the combined analysis of the Sunyaev-Zel'dovich effect and X-ray observations of galaxy clusters is systematically lower than those from other methods by 10-15...
Kashikawa, Nobunari, Kitayama, Tetsu, Doi, Mamoru, Misawa, Toru, Komiyama, Yutaka, Ota, Kazuaki
We carried out a target survey for Lyman break galaxies (LBGs) and Lyman alpha emitters (LAEs) around QSO SDSS J0211-0009 at z=4.87. The deep and wide broadband and narrowband imaging simultaneously...
Kawahara, Hajime, Suto, Yasushi, Kitayama, Tetsu, Sasaki, Shin, Shimizu, Mamoru, Rasia, Elena, ...
The origin of the recently reported systematic bias in the spectroscopic temperature of galaxy clusters is investigated using cosmological hydrodynamical simulations. We find that the local...
Early Cosmological HII/HeIII Regions and Their Impact on Second-Generation Star Formation (2006)
Yoshida, Naoki, Oh, S. Peng, Kitayama, Tetsu, Hernquist, Lars
(Abridged) We present the results of three-dimensional radiation-hydrodynamics simulations of the formation and evolution of early HII/HeIII regions around the first stars. Cooling (by H2 and HD) and...
Shimizu, Mamoru, Kitayama, Tetsu, Sasaki, Shin, Suto, Yasushi
We revisit the estimate of the mass fluctuation amplitude, sigma_8, from the observational X-ray cluster abundance. In particular, we examine the effect of the systematic difference between the...
L_X-T Relation and Related Properties of Galaxy Clusters (2005)
Ota, Naomi, Kitayama, Tetsu, Masai, Kuniaki, Mitsuda, Kazuhisa
An observational approach is presented to constrain the global structure and evolution of the intracluster medium based on the ROSAT and ASCA distant cluster sample. From statistical analysis of the...
Infrared Emission from Intracluster Dust Grains and Constraints on Dust Properties (2005)
Yamada, Kenkichi, Kitayama, Tetsu
For 117 clusters of galaxies, we explore the detectability of intracluster dust grains by current and future infrared facilities, taking into account both collisional heating and sputtering of grains...
Kitayama, Tetsu, Yoshida, Naoki
We study the evolution of supernova (SN) remnants of the first stars, taking proper account of the radiative feedback of the progenitor stars on the surroundings. We carry out a series of...
Ota, Naomi, Morita, Umeyo, Kitayama, Tetsu, Ohashi, Takaya
We present an analysis of Chandra X-ray observations of a compact group of galaxies, HCG 80 (z=0.03). The system is a spiral-only group composed of four late-type galaxies, and has a high-velocity...
Quasi-hydrostatic intracluster gas under radiative cooling (2004)
Masai, Kuniaki, Kitayama, Tetsu
Quasi-hydrostatic cooling of the intracluster gas is studied. In the quasi-hydrostatic model, work done by gravity on the inflow gas with dP \neq 0, where P is the gas pressure, is taken into account...
X-ray Measurement of Dark Matter "Temperature" in Abell 1795 (2004)
Ikebe, Yasushi, Boehringer, Hans, Kitayama, Tetsu
We present a method from an X-ray observation of a galaxy cluster to measure the radial profile of the dark matter velocity dispersion, sigma_DM, and to compare the dark matter ``temperature''...
Monte-Carlo Modeling of Non-Gravitational Heating Processes in Galaxy Clusters (2003)
Shimizu, Mamoru, Kitayama, Tetsu, Sasaki, Shin, Suto, Yasushi
We consider non-gravitational heating effects on galaxy clusters on the basis of the Monte-Carlo modeling of merging trees of dark matter halos combined with the thermal evolution of gas inside each...
Shimizu, Mamoru, Kitayama, Tetsu, Sasaki, Shin, Suto, Yasushi
We derive constraints on the mass-temperature relation of galaxy clusters from their observed luminosity-temperature relation and X-ray temperature function. Adopting the isothermal gas in...
Shimizu, Mamoru, Kitayama, Tetsu, Sasaki, Shin, Suto, Yasushi
We examine the reliability of the merger trees generated for the Monte-Carlo modeling of galaxy formation. In particular we focus on the cold gas fraction predicted from the merger trees with...
A New Measurement of the X-ray Temperature Function of Clusters of Galaxies (2001)
Ikebe, Yasushi, Reiprich, Thomas H., Boehringer, Hans, Tanaka, Yasuo, Kitayama, Tetsu
We present a newly measured X-ray temperature function of galaxy clusters using a complete flux-limited sample of 61 clusters. The sample is constructed with the total survey area of 8.14 steradians...
CMB anisotropy from spatial correlations of clusters of galaxies (2000)
Komatsu, Eiichiro, Kitayama, Tetsu, Refregier, Alexandre, Spergel, David N., Pen, Ue-Li
The SZ effect from clusters of galaxies is a dominant source of secondary CMB anisotropy in the low-redshift universe. We present analytic predictions for the CMB power spectrum from massive halos...
Komatsu, Eiichiro, Matsuo, Hiroshi, Kitayama, Tetsu, Hattori, Makoto, Kawabe, Ryohei, Kohno, Kotaro, ...
We report on mapping observations toward the region of the most luminous X-ray cluster RXJ1347-1145 (z=0.45) through the Sunyaev-Zel'dovich effect at 21GHz and 150GHz with the Nobeyama 45-m...
Forming Clusters of Galaxies as the Origin of Unidentified GeV Gamma-Ray Sources (2000)
Totani, Tomonori, Kitayama, Tetsu
Over half of GeV gamma-ray sources observed by the EGRET experiment have not yet been identified as known astronomical objects. There is an isotropic component of such unidentified sources, whose...
Collapse of Low Mass Clouds in the Presence of UV Radiation Field (2000)
The collapse of marginally Jeans unstable primordial gas clouds in the presence of UV radiation field is discussed. Assuming that the dynamical collapse proceeds approximately in an isothermal...
Eiichiro Komatsu, Hiroshi Matsuo, Tetsu Kitayama, Makoto Hattori, Ryohei Kawabe, Kotaro Kohno, ...
We report on mapping observations toward the region of the most luminous X-ray cluster RX J1347-- 1145 (z = 0:45) through the Sunyaev--Zel'dovich effect at 21 GHz and 150 GHz with the Nobeyama...
Sunyaev - Zel'dovich fluctuations from spatial correlations between clusters of galaxies (1999)
Komatsu, Eiichiro, Kitayama, Tetsu
We present angular power spectra of the cosmic microwave background radiation anisotropy due to fluctuations of the Sunyaev-Zel'dovich (SZ) effect through clusters of galaxies. A contribution from...
Formation of Sub-galactic Clouds under UV Background Radiation (1999)
Kitayama, Tetsu, Ikeuchi, Satoru
The effects of the UV background radiation on the formation of sub-galactic clouds are studied by means of one-dimensional hydrodynamical simulations. The radiative transfer of the ionizing photons...
Suto, Yasushi, Yamamoto, Kazuhiro, Kitayama, Tetsu, Jing, Y. P.
We have developed a model to describe two-point correlation functions of clusters of galaxies in X-ray flux-limited surveys. Our model properly takes account of nonlinear gravitational evolution of...
Cosmological Implications of Galaxy Clusters in X-Ray, Millimeter, and Submillimeter Bands (1999)
Suto, Yasushi, Kitayama, Tetsu, Komatsu, Eiichiro, Hattori, Makoto, Kawabe, Ryohei, Matsuo, Hiroshi, ...
Cosmological implications of clusters of galaxies are discussed with particular attention to their importance in probing the cosmological parameters. More specifically we compute the number counts of...
Komatsu, Eiichiro, Kitayama, Tetsu, Suto, Yasushi, Hattori, Makoto, Kawabe, Ryohei, Matsuo, Hiroshi, ...
We report on the detection of the Sunyaev -- Zel'dovich (SZ) signals toward the most luminous X-ray cluster RXJ1347-1145 at Nobeyama Radio Observatory (21 and 43 GHz) and at James Clerk Maxwell...
Sunyaev-Zeldovich Fluctuations From Spatial Correlations Between Clusters Of Galaxies (1999)
E. Komatsu, Eiichiro Komatsu, Tetsu Kitayama
We present angular power spectra of the cosmic microwave background radiation anisotropy due to fluctuations of the Sunyaev-Zeldovich (SZ) effect through clusters of galaxies. A contribution from the...
Cosmological Implications of X-ray Clusters of Galaxies (1998)
Suto, Yasushi, Kitayama, Tetsu, Sasaki, Shin
Cosmological implications of clusters of galaxies are discussed with particular attention to their importance in probing the cosmological parameters. More specifically we compute the number counts of...
Kitayama, Tetsu, Sasaki, Shin, Suto, Yasushi
We compute the number counts of clusters of galaxies, the logN-logS relation, in several X-ray and submm bands on the basis of the Press-Schechter theory. We pay particular attention to a set of...
Kitayama, Tetsu, Suto, Yasushi
We find that the observed log N - log S relation of X-ray clusters can be reproduced remarkably well with a certain range of values for the fluctuation amplitude $\sigma_8$ and the cosmological...
Kitayama, Tetsu, Suto, Yasushi
Temperature and luminosity functions of X-ray clusters are computed semi-analytically, combining a simple model for the cluster gas properties with the distribution functions of halo formation epochs...
Formation rate of gravitational structures and the cosmic X-ray background radiation (1996)
Kitayama, Tetsu, Suto, Yasushi
Analytical expressions for the rates of formation and destruction of gravitationally bound systems are derived assuming that they are originated from primordial random-Gaussian density fluctuations....