Kobayashi, Masakazu A. R., Totani, Tomonori, Nagashima, Masahiro
We present theoretical predictions of UV continuum luminosity function (UV LF) and Lya equivalent width (EW) distribution of Lyman alpha emitters (LAEs) in the framework of the hierarchical...
Dynamical response to supernova-induced gas removal in spiral galaxies with dark matter halo (2008)
Koyama, Hiroko, Nagashima, Masahiro, Kakehata, Takayuki, Yoshii, Yuzuru
We investigate the dynamical response, in terms of disc size and rotation velocity, to mass loss by supernovae in the evolution of spiral galaxies. A thin baryonic disc having the Kuzmin density...
The origin of globular cluster systems from cosmological simulations (2008)
Bekki, Kenji, Yahagi, Hideki, Nagashima, Masahiro, Forbes, Duncan A.
We investigate the structural, kinematical and chemical properties of globular cluster systems (GCss) in galaxies of different Hubble types in a self-consistent manner based on high-resolution...
The origin of globular cluster systems from cosmological simulations (2008)
Bekki, Kenji, Yahagi, Hideki, Nagashima, Masahiro, Forbes, Duncan A.
We investigate the structural, kinematical and chemical properties of globular cluster systems (GCss) in galaxies of different Hubble types in a self-consistent manner based on high-resolution...
The origin of globular cluster systems from cosmological simulations (2008)
Bekki, Kenji, Yahagi, Hideki, Nagashima, Masahiro, Forbes, Duncan A.
We investigate the structural, kinematical and chemical properties of globular cluster systems (GCss) in galaxies of different Hubble types in a self-consistent manner based on high-resolution...
The origin of globular cluster systems from cosmological simulations (2008)
Bekki, Kenji, Yahagi, Hideki, Nagashima, Masahiro, Forbes, Duncan A.
We investigate the structural, kinematical and chemical properties of globular cluster systems (GCss) in galaxies of different Hubble types in a self-consistent manner based on high-resolution...
The Reionization and Galaxy Evolution Probed by z=7 Lyman Alpha Emitters (2007)
Ota, Kazuaki, Iye, Masanori, Kashikawa, Nobunari, Shimasaku, Kazuhiro, Kobayashi, Masakazu A. R., Totani, Tomonori, ...
We made a narrowband NB973 (bandwidth of 200A at 9755A) imaging of the Subaru Deep Field (SDF) and found two z=7 Lyman alpha emitter (LAE) candidates down to NB973=24.9. Carrying out deep follow-up...
Lyman Alpha Emitters in the Hierarchically Clustering Galaxy Formation (2007)
Kobayashi, Masakazu A. R., Totani, Tomonori, Nagashima, Masahiro
We present a new theoretical model for the luminosity functions (LFs) of Lyman alpha (Lya) emitting galaxies in the framework of hierarchical galaxy formation. We extend a semi-analytic model of...
Bekki, Kenji, Yahagi, Hideki, Nagashima, Masahiro, Forbes, Duncan A.
Recent observations have reported that the Galactic globular clusters (GCs) with unusually extended horizontal-branch (EHB) morphologies show a significantly lower velocity dispersion compared with...
Bekki, Kenji, Yahagi, Hideki, Nagashima, Masahiro, Forbes, Duncan A.
Recent observations have reported that the Galactic globular clusters (GCs) with unusually extended horizontal-branch (EHB) morphologies show a significantly lower velocity dispersion compared with...
Bekki, Kenji, Yahagi, Hideki, Nagashima, Masahiro, Forbes, Duncan A.
Recent observations have reported that the Galactic globular clusters (GCs) with unusually extended horizontal-branch (EHB) morphologies show a significantly lower velocity dispersion compared with...
Bekki, Kenji, Yahagi, Hideki, Nagashima, Masahiro, Forbes, Duncan A.
Recent observations have reported that the Galactic globular clusters (GCs) with unusually extended horizontal-branch (EHB) morphologies show a significantly lower velocity dispersion compared with...
Enoki, Motohiro, Nagashima, Masahiro
A compact binary in an eccentric orbit radiates gravitational waves (GWs) at all integer harmonics of its orbital frequency. In this study, we investigate the effect of orbital eccentricity on the...
How Long Can Tiny HI Clouds Survive? (2006)
Nagashima, Masahiro, Inutsuka, Shu-ichiro, Koyama, Hiroshi
We estimate the evaporation timescale for spherical HI clouds consisting of the cold neutral medium surrounded by the warm neutral medium. We focus on clouds smaller than 1pc, which corresponds to...
Kashikawa, Nobunari, Yoshida, Makiko, Shimasaku, Kazuhiro, Nagashima, Masahiro, Yahagi, Hideki, Ouchi, Masami, ...
We explored the clustering properties of Lyman Break Galaxies (LBGs) at z=4 and 5 with an angular two-point correlation function on the basis of the very deep and wide Subaru Deep Field data. We...
Nagashima, Masahiro, Yahagi, Hideki, Enoki, Motohiro, Yoshii, Yuzuru, Gouda, Naoteru
We construct the Numerical Galaxy Catalog ($\nu$GC), based on a semi-analytic model of galaxy formation combined with high-resolution N-body simulations in a $\Lambda$-dominated flat cold dark matter...
The metal enrichment of elliptical galaxies in hierarchical galaxy formation models (2005)
Nagashima, Masahiro, Lacey, Cedric G., Okamoto, Takashi, Baugh, Carlton M., Frenk, Carlos S., Cole, Shaun
We investigate the metal enrichment of elliptical galaxies in the framework of hierarchical models of galaxy formation. The semi-analytical model we use in this Letter, which has been used to study...
Gamma-Ray Background from Neutralino Annihilation in the First Cosmological Objects (2005)
Oda, Takeshi, Totani, Tomonori, Nagashima, Masahiro
The paradigm of the neutralino dark matter predicts that the first gravitationally bound objects are earth-mass sized microhaloes, which would emit annihilation gamma-rays. Here we show that, though...
Nagashima, Masahiro, Koyama, Hiroshi, Inutsuka, Shu-ichiro
We analyze the evaporation and condensation of spherical and cylindrical HI clouds of the cold neutral medium surrounded by the warm neutral medium. Because the interstellar medium including those...
Enoki, Motohiro, Inoue, Kaiki T., Nagashima, Masahiro, Sugiyama, Naoshi
We investigate the expected gravitational wave emission from coalescing supermassive black hole (SMBH) binaries resulting from mergers of their host galaxies. We employ a semi-analytic model of...
Inoue, Susumu, Nagashima, Masahiro
It is shown that inverse Compton gamma-rays from electrons accelerated in large scale structure formation shocks can be crucially affected by non-gravitational effects such as radiative cooling and...
Damped Lyman alpha Absorbing Galaxies At Low Redshifts z (2004)
Okoshi, Katsuya, Nagashima, Masahiro
We investigate Damped Ly-alpha absorbing galaxies (DLA galaxies) at low redshifts z
The metal enrichment of the intracluster medium in hierarchical galaxy formation models (2004)
Nagashima, Masahiro, Lacey, Cedric G., Baugh, Carlton M., Frenk, Carlos S., Cole, Shaun
We investigate the metal enrichment of the intracluster medium (ICM) in the framework of hierarchical models of galaxy formation. We calculate the formation and evolution of galaxies and clusters...
Hierarchical Formation of Galaxies with Dynamical Response to Supernova-Induced Gas removal (2004)
Nagashima, Masahiro, Yoshii, Yuzuru
We reanalyze the formation and evolution of galaxies in the hierarchical clustering scenario. Using a semi-analytic model (SAM) of galaxy formation described in this paper, which we hereafter call...
Type Ia supernovae in a hierarchical galaxy formation model: the Milky Way (2004)
Nagashima, Masahiro, Okamoto, Takashi
We investigate chemical evolution in Milky Way-like galaxies based on the cold dark matter model in which cosmic structures form via hierarchical merging. We introduce chemical enrichment due to type...
Enoki, Motohiro, Inoue, Kaiki T., Nagashima, Masahiro, Sugiyama, Naoshi
We investigate the expected gravitational wave emission from coalescing supermassive black hole (SMBH) binaries resulting from mergers of their host galaxies. When galaxies merge, the SMBHs in the...
The roles of ram-pressure stripping and minor mergers in evolution of galaxies (2004)
Okamoto, Takashi, Nagashima, Masahiro
We investigate environmental effects on evolution of bright cluster galaxies in a Lambda-dominated cold dark matter universe using a combination of dissipationless N-body simulations and a...
Mass Function of Low Mass Dark Halos (2004)
Yahagi, Hideki, Nagashima, Masahiro, Yoshii, Yuzuru
The mass function of dark halos in a Lambda-dominated cold dark matter (LambdaCDM) universe is investigated. 529 output files from five runs of N-body simulations are analyzed using the...
Chemical Enrichment in Damped Lyman Alpha Systems From Hierarchical Galaxy Formation Models (2003)
Okoshi, Katsuya, Nagashima, Masahiro, Gouda, Naoteru, Yoshioka, Satoshi
We investigate chemical enrichment in Damped Lyman alpha (DLA) systems in the hierarchical structure formation scenario using a semi-analytic model of galaxy formation. The model developed by...
Searching for a Long Cosmic String Through the Gravitational Lensing Effect (2003)
Shirasaki, Yuji, Matsuzaki, Ei-ichi, Mizumoto, Yoshihiko, Kakimoto, Fumio, Ogio, Syoichi, Yasuda, Naoki, ...
It has been suggested that cosmic strings produced at a phase transition in the early universe can be the origin of the extremely high energy cosmic rays (EHCR) observed by AGASA above 10^20 eV....
Dynamical response to supernova-induced gas removal in two-component spherical galaxies (2002)
Nagashima, Masahiro, Yoshii, Yuzuru
We investigate dynamical response on size and velocity dispersion to mass loss by supernovae in formation of two-component spherical galaxies composed of baryon and dark matter. Three-dimensional...
Kashikawa, Nobunari, Takata, Tadafumi, Ohyama, Youichi, Yoshida, Michitoshi, Maihara, Toshinori, Iwamuro, Fumihide, ...
We have constructed a very deep K'-selected multicolor BVRIz'JK' sample of 439 field galaxies. Photometric redshifts for sample galaxies were estimated. The overall redshift distribution N(z) for the...
Relations Between Environments of Quasars and Galaxy Formation (2002)
Enoki, Motohiro, Nagashima, Masahiro, Gouda, Naoteru
We investigate the environments of quasars such as number distribution of galaxies using a semi-analytic model which includes both galaxy and quasar formations based on the hierarchical clustering...
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...
Analytic Approach to the Cloud-in-cloud Problem for Non-Gaussian Density Fluctuations (2001)
Inoue, Kaiki Taro, Nagashima, Masahiro
We revisit the cloud-in-cloud problem for non-Gaussian density fluctuations. We show that the extended Press-Schechter (EPS) formalism for non-Gaussian fluctuations has a flaw in describing mass...
A Solution to the Missing Link in the Press-Schechter Formalism (2001)
The Press-Schechter (PS) formalism for mass functions of the gravitationally collapsed objects is reanalyzed. It has been suggested by many authors that the PS mass function agrees well with the mass...
Environmental Effects on Evolution of Cluster Galaxies in a LCDM Universe (2001)
Okamoto, Takashi, Nagashima, Masahiro
We investigate environmental effects on evolution of bright cluster galaxies in a $\Lambda$ dominated cold dark matter universe using a combination of dissipationless N-body simulations and a...
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...
Okamoto, Takashi, Nagashima, Masahiro
We present a model to investigate the formation and evolution of cluster galaxies using cosmological N-body simulations. The N-body simulations are used to make merging history trees of dark halos....
Nagashima, Masahiro, Gouda, Naoteru
We examined the physical origin of the colour-magnitude relation of elliptical galaxies in clusters of galaxies in the hierarchical clustering scenario by using a semi-analytic model of galaxy...
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...
Effects of the UV background radiation on galaxy formation (1998)
Nagashima, Masahiro, Gouda, Naoteru, Sugiura, Norimasa
We investigate the effects of the UV background radiation on galaxy formation by using the semi-analytic model including the photoionization process. The semi-analytic model is based on Cole et al....
Effects of Merging Histories on Angular Momentum Distribution of Dark Matter Haloes (1997)
Nagashima, Masahiro, Gouda, Naoteru
The effects of merging histories of proto-objects on the angular momentum distributions of the present-time dark matter haloes are analysed. An analytical approach to the analysis of the angular...
The Effect of Spatial Correlations on Merger Trees of Dark Matter Haloes (1996)
Nagashima, Masahiro, Gouda, Naoteru
The effects of spatial correlations of density fluctuations on merger histories of dark matter haloes (so-called `{\it merger trees}') are analysed. We compare the mass functions of dark haloes...