Fujita, Yutaka, Hayashida, Kiyoshi, Takahashi, Hiroaki, Takahara, Fumio
We present the analysis of Suzaku observations of the young open cluster Westerlund 2, which is filled with diffuse X-ray emission. We found that the emission consists of three thermal components or...
Is the PAMELA anomaly caused by the supernova explosions near the Earth? (2009)
Fujita, Yutaka, Kohri, Kazunori, Yamazaki, Ryo, Ioka, Kunihito
We show that the anomaly of the positron fraction observed by the PAMELA experiment can be attributed to recent supernova explosion(s) in a dense gas cloud (DC) near the Earth. Protons are...
Recent numerical relativity simulations have shown that the emission of gravitational waves at the merger of two black holes gives a recoil kick to the final black hole. We follow the orbits of a...
X-Ray Emission from a Supermassive Black Hole Ejected from the Center of a Galaxy (2008)
Recent studies have indicated that the emission of gravitational waves at the merger of two black holes gives a kick to the final black hole. If the supermassive black hole at the center of a disk...
Suzaku Observation of the Ophiuchus Galaxy Cluster: One of the Hottest Cool Core Clusters (2008)
Fujita, Yutaka, Hayashida, Kiyoshi, Nagai, Masaaki, Inoue, Susumu, Matsumoto, Hironori, Okabe, Nobuhiro, ...
We present the analysis of a Suzaku observation of the Ophiuchus galaxy cluster. We confirmed that the cluster has a cool core. While the temperature of the intracluster medium (ICM) decreases toward...
Influence of AGN Outbursts on the Surrounding Galaxies (2007)
We study the influence of a strong AGN outburst on the surrounding galaxies. The AGN is assumed to reside in a group of galaxies, and an outburst excites a shock wave in the hot gas in the group. We...
A Chandra Observation of Abell 13: Investigating the Origin of the Radio Relic (2007)
Juett, Adrienne M., Sarazin, Craig L., Clarke, Tracy E., Andernach, Heinz, Ehle, Matthias, Fujita, Yutaka, ...
We present results from the Chandra X-ray observation of Abell 13, a galaxy cluster that contains an unusual noncentral radio source, also known as a radio relic. This is the first pointed X-ray...
Nonthermal Emission Associated with Strong AGN Outbursts at the Centers of Galaxy Clusters (2007)
Fujita, Yutaka, Kohri, Kazunori, Yamazaki, Ryo, Kino, Motoki
Recently, strong AGN outbursts at the centers of galaxy clusters have been found. Using a simple model, we study particle acceleration around a shock excited by an outburst and estimate nonthermal...
Fujita, Yutaka, Tawa, Noriaki, Hayashida, Kiyoshi, Takizawa, Motokazu, Matsumoto, Hironori, Okabe, Nobuhiro, ...
We present an analysis of a Suzaku observation of the link region between the galaxy clusters A399 and A401. We obtained the metallicity of the intracluster medium (ICM) up to the cluster virial...
The Origin of Ripples in Cool Cores of Galaxy Clusters: Heating by MHD Waves? (2007)
Fujita, Yutaka, Suzuki, Takeru K., Kudoh, Takahiro, Yokoyama, Takaaki
We consider MHD waves as a heating source of cool cores of galaxy clusters. In particular, we focus on transverse waves (Alfven waves), because they can propagate a longer distance than longitudinal...
Reiprich, Thomas H., Hudson, Daniel S., Nenestyan, Oxana-Elena, Sato, Kosuke, Ishisaki, Yoshitaka, Hoshino, Akio, ...
Fujita, Yutaka, Kato, Tsunehiko N., Okabe, Nobuhiro
The Weibel instability could be responsible for the generation of magnetic fields in various objects such as gamma-ray bursts, jets from active galactic nuclei, and clusters of galaxies. Using...
The Difficulty of the Heating of Cluster Cooling Flows by Sound Waves and Weak Shocks (2006)
Fujita, Yutaka, Suzuki, Takeru Ken
We investigate heating of the cool core of a galaxy cluster through the dissipation of sound waves and weak shocks excited by the activities of the central active galactic nucleus (AGN). Using a weak...
Disk galaxies in a cluster of galaxies are moving in hot gas filling the cluster. Generally, they are moving at transonic or supersonic velocities. If ram-pressure stripping is insufficient to...
The Generation of Magnetic Fields and X-ray Observations (2006)
Fujita, Yutaka, Kato, Tsunehiko N.
We show that strong magnetic fields can be generated at shock waves associated with formation of galaxies or clusters of galaxies by the Weibel instability, an instability in collisionless plasmas....
Fujita, Yutaka, Sarazin, Craig L., Sivakoff, Gregory R.
We present an analysis of Chandra observations of the galaxy clusters A2670 and A2107. Their cD galaxies have large peculiar velocities (>200km/s) and thus the clusters appear to be undergoing...
Fujita, Yutaka, Kato, Tsunehiko N.
We propose that strong magnetic fields should be generated at shock waves associated with formation of galaxies or clusters of galaxies by the Weibel instability, an instability in collisionless...
On Heating of Cluster Cooling Flows by Sound Waves (2005)
Fujita, Yutaka, Suzuki, Takeru Ken
We investigate heating of the cool core of a galaxy cluster through the dissipation of sound waves excited by the activities of the central active galactic nucleus (AGN). Using a weak shock theory,...
A Simple Measurement of Turbulence in Cores of Galaxy Clusters (2005)
Using a simple model, we study the effects of turbulence on the motion of bubbles produced by AGN jet activities in the core of a galaxy cluster. We focus on the turbulence with scales larger then...
Fujita, Yutaka, Matsumoto, Tomoaki, Wada, Keiichi, Furusho, Tae
This is the first attempt to construct detailed X-ray spectra of clusters of galaxies from the results of high-resolution hydrodynamic simulations and simulate X-ray observations in order to study...
XMM-Newton Observations of A133: A Weak Shock Passing through the Cool Core (2004)
Fujita, Yutaka, Sarazin, Craig L., Reiprich, Thomas H., Andernach, H., Ehle, M., Murgia, M., ...
We use XMM-Newton observations of the cluster of galaxies A133 to study the X-ray spectrum of the intracluster medium (ICM). We find a cold front to the southeast of the cluster core. From the...
Fujita, Yutaka, Matsumoto, Tomoaki, Wada, Keiichi
Based on high-resolution two-dimensional hydrodynamic simulations, we show that the bulk gas motions in a cluster of galaxies, which are naturally expected during the process of hierarchical...
The Evolution of Galaxies in and around Clusters at High-Redshift (2004)
Fujita, Yutaka, Goto, Tomotsugu
In this paper, we focus on ram-pressure stripping and evaporation of disk galaxies in and around a cluster. We show that the evolution of the disk surface density affects the efficiency of...
Can Supermassive Black Holes Sufficiently Heat Cool Cores of Galaxy Clusters? (2004)
Fujita, Yutaka, Reiprich, Thomas H.
Activities of a supermassive black hole or active galactic nucleus in the central galaxy of a cluster of galaxies have been promising candidates for heating sources of cool cluster cores. We estimate...
The Morphology-Density Relation in the Sloan Digital Sky Survey (2003)
Goto, Tomotsugu, Yamauchi, Chisato, Fujita, Yutaka, Okamura, Sadanori, Sekiguchi, Maki, Smail, Ian, ...
We have studied the morphology-density relation and morphology--cluster-centric-radius relation using a volume limited sample (0.05$
Pre-Processing of Galaxies before Entering a Cluster (2003)
We consider several mechanisms that possibly affect the evolution of disk galaxies in clusters using analytical models based on a hierarchical clustering scenario. We especially focus on the...
Tsunamis in Galaxy Clusters: Heating of Cool Cores by Acoustic Waves (2003)
Fujita, Yutaka, Suzuki, Takeru Ken, Wada, Keiichi
Using an analytical model and numerical simulations, we show that acoustic waves generated by turbulent motion in intracluster medium effectively heat the central region of a so-called ``cooling...
Infant Galaxy Clusters at Low Redshifts? (2003)
The population and population composition of galaxies in galaxy clusters at present reflect the mass of the clusters and the mass growth of the galaxies in the past. We investigate them for six...
Properties of the Brightest Cluster Galaxy and Its Host Cluster (2002)
Katayama, Haruyoshi, Hayashida, Kiyoshi, Takahara, Fumio, Fujita, Yutaka
We investigate the relation between the properties of Brightest Cluster Galaxies (BCGs) and those of their host clusters. To quantify the properties of cluster hot gas, we employ the parameter $Z$ of...
Nonthermal Emissions from Particles Accelerated by Turbulence in Clusters of Galaxies (2002)
Fujita, Yutaka, Takizawa, Motokazu, Sarazin, Craig L.
We consider nonthermal emission from clusters of galaxies produced by particle acceleration by resonant scattering of Alfv\'{e}n waves driven by fluid turbulence through the Lighthill mechanism in...
Fujita, Yutaka, Sarazin, Craig L., Nagashima, Masahiro, Yano, Taihei
We construct an analytical model of the mass distribution function of subhalos in a galaxy cluster in the context of the cold dark matter (CDM) theory. Our model takes account of two important...
Chandra Observations of the Disruption of the Cool Core in Abell 133 (2002)
Fujita, Yutaka, Sarazin, Craig L., Kempner, Joshua C., Rudnick, L., A, O. B. Slee, Roy, . L., ...
We present the analysis of a Chandra observation of the galaxy cluster Abell 133, which has a cooling flow core, a central radio source, and a diffuse, filamentary radio source which has been...
Nonthermal Emissions From Particles Accelerated By Turbulence (2002)
In Clusters Of, Yutaka Fujita, Craig L. Sarazin
We consider nonthermal emission from clusters of galaxies produced by particle acceleration by resonant scattering of Alfve n waves driven by fluid turbulence through the Lighthill mechanism in the...
Nonthermal Emission from Accreting and Merging Clusters of Galaxies (2001)
Fujita, Yutaka, Sarazin, Craig L.
We compare the nonthermal emission from clusters of galaxies undergoing minor mergers (``accreting'' clusters) and major mergers (``merging'' clusters). For accreting clusters, the radial...
Heating of Intracluster Gas by Jet Activities of AGN: Is the "Preheating" Scenario Realistic? (2001)
Yamada, Masako, Fujita, Yutaka
We investigate the non-gravitational heating of hot gas in clusters of galaxies (intracluster medium; ICM) on the assumption that the gas is heated well before cluster formation ('preheating'). We...
Enoki, Motohiro, Takahara, Fumio, Fujita, Yutaka
We investigate statistical properties of galaxy clusters in the context of hierarchical clustering scenario, taking account of their formation epoch distribution, motivated by the recent finding by...
Heating of X-Ray Hot Gas in Groups by Blast Waves (2001)
In order to find the conditions which determine whether X-Ray hot gas in galaxy groups (intragroup gas; IGG) is heated externally or internally, we investigate the evolution of blast waves in galaxy...
Ram-Pressure Stripping of Galaxies in High-Redshift Clusters and Influence of ICM Heating (2000)
We have investigated the ram-pressure stripping of disk galaxies in clusters at various redshifts and in cluster progenitors; the clusters grow up on a hierarchical clustering scenario. We consider a...
The Maximum Effect of Thermal Instability on Galactic Outflows (2000)
We have investigated steady, radial gas outflows (or winds) from galaxies and the development of thermal instability in the hot gas. In order to see the maximum influence of the instability on the...
Fujita, Yutaka, Nagashima, Masahiro, Gouda, Naoteru
In order to constrain parameters in galaxy formation theories, especially those for a star formation process, we investigate cold gas in elliptical galaxies. We calculate the detection rate of cold...
The Variation of Gas Mass Distribution in Galaxy Clusters: Effects of Preheating and Shocks (2000)
Fujita, Yutaka, Takahara, Fumio
We investigate the origin of the variation of the gas mass fraction in the core of galaxy clusters, which was indicated by our work on the X-ray fundamental plane. The adopted model supposes that the...
Global Relationships among Physical Properties of Galaxy Cluster Cores (1999)
Fujita, Yutaka, Takahara, Fumio
Using X-ray data, we investigate interrelations between gas density rho_0, virial density rho_vir, core radius R, temperature T, entropy S_gas, and metal abundance Z in the core region of clusters of...
Fujita, Yutaka, Tosaki, Tomoka, Nakamichi, Akika, Kuno, Nario
We have searched for molecular gas in the cD galaxy of a poor cluster of galaxies AWM7 using Nobeyama 45 m telescope. We do not detect CO emission in the galaxy. Our limit of molecular gas in the...
The X-ray Fundamental Plane and $L_X-T$ Relation of Clusters of Galaxies (1999)
Fujita, Yutaka, Takahara, Fumio
We analyze the relations among central gas density, core radius, and temperature of X-ray clusters by plotting the observational data in the three-dimensional ($\log \rho_0$, $\log R$, and $\log T$)...
Cosmological Implications of the Fundamental Relations of X-ray Clusters (1999)
Fujita, Yutaka, Takahara, Fumio
Based on the two-parameter family nature of X-ray clusters of galaxies obtained in a separate paper, we discuss the formation history of clusters and cosmological parameters of the universe....
Is Galactic Star Formation Activity Increased During Cluster Mergers? (1999)
Fujita, Yutaka, Takizawa, Motokazu, Nagashima, Masahiro, Enoki, Motohiro
We have investigated the effect of pressure from intracluster medium (ICM) on disk galaxies in merging clusters. The ram-pressure on the galaxies rapidly increases when two clusters collide. This...
Fujita, Yutaka, Nagashima, Masahiro
Using a simple model of molecular cloud evolution, we have quantitatively estimated the change of star formation rate (SFR) of a disk galaxy falling radially into the potential well of a cluster of...
A simple model is constructed to evaluate the change of star formation rate of a disk galaxy due to environmental effects in clusters of galaxies. Three effects, (1) tidal force from the potential...
Evolution of Multiphase Hot Interstellar Medium in Elliptical Galaxies (1997)
Fujita, Yutaka, Fukumoto, Junji, Okoshi, Katsuya
We present the results of a variety of simulations concerning the evolution of multiphase (inhomogeneous) hot interstellar medium (ISM) in elliptical galaxies. We assume the gases ejected from stars...
Iron abundance distribution is now known for 12 clusters of galaxies. For some clusters (e.g. Centaurus) the observed abundance increases toward the cluster center, while for the others (e.g. Coma...
この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。
この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。
Lipid Droplet-Associated Proteins Protect Renal Tubular Cells from Fatty Acid-Induced Apoptosis
Urahama, Yoshimichi, Ohsaki, Yuki, Fujita, Yutaka, Maruyama, Shoichi, Yuzawa, Yukio, Matsuo, Seiichi, ...
Proteinuria is a major cause of tubulointerstitial kidney damage, and free fatty acids bound to albumin are thought to play an important role in its pathogenesis. However, the mechanism whereby...