Formation of High-redshift (z>6) Quasars Driven by Nuclear Starbursts (2009)
Kawakatu, Nozomu, Wada, Keiichi
Based on the physical model of a supermassive black hole (SMBH) growth via gas accretion in a circumnuclear disk (CND) proposed by Kawakatu & Wada (2008), we describe the formation of high-$z$ ($z >...
Kawakatu, Nozomu, Kino, Motoki, Nagai, Hiroshi
We argue that the origin of "FRI/FRI{-.1em}I dichotomy" -- the division between Fanaroff-Riley class I (FRI) with subsonic lobes and class I{-.1em}I (FRI{-.1em}I) radio sources with supersonic lobes...
Kawakatu, Nozomu, Nagao, Tohru, Woo, Jong-Hak
We investigate the optical emission-line flux ratios of narrow-line regions, in order to determine whether the formation of AGN jets requires specific accretion conditions. We find that bright...
Fate of baby radio galaxies: Dead or Alive ? (2008)
Kawakatu, Nozomu, Nagai, Hiroshi, Kino, Motoki
In order to reveal the long-term evolution of relativistic jets in active galactic nuclei (AGNs), we examine the dynamical evolution of variously-sized radio galaxies [i.e., compact symmetric objects...
Long gamma-ray bursts and their host galaxies at high redshift (2008)
Lapi, Andrea, Kawakatu, Nozomu, Bosnjak, Zeljka Marija, Celotti, Annalisa, Bressan, Alessandro, Granato, Gian Luigi, ...
Motivated by the recent observational and theoretical evidence that long Gamma-Ray Bursts (GRBs) are likely associated with low metallicity, rapidly rotating massive stars, we examine the...
The Fate of Young Radio Galaxies: Decelerations Inside Host Galaxies? (2008)
Kawakatu, Nozomu, Nagai, Hiroshi, Kino, Motoki
We examine the evolution of variously-sized radio galaxies [i.e., compact symmetric objects (CSOs), medium-size symmetric objects (MSOs), Fanaroff-Riley type II radio galaxies (FRIIs)], by comparing...
Coevolution of Supermassive Black Holes and Circumnuclear Disks (2008)
Kawakatu, Nozomu, Wada, Keiichi
We propose a new evolutionary model of a supermassive black hole (SMBH) and a circumnuclear disk (CND), taking into account the mass-supply from a host galaxy and the physical states of CND. In the...
Watabe, Yasuyuki, Kawakatu, Nozomu, Imanishi, Masatoshi
We investigated the correlation between nuclear/circumnuclear starbursts around the active galactic nuclei (AGNs) and the AGN activities for 43 Seyfert galaxies in the CfA and 12 micron samples. We...
Type I Ultraluminous Infrared Galaxies: Transition Stage from ULIRGs to QSOs (2007)
Kawakatu, Nozomu, Anabuki, Naohisa, Nagao, Tohru, Umemura, Masayuki, Nakagawa, Takao
We examine whether the ultraluminous infrared galaxies that contain a type I Seyfert nucleus (a type I ULIRG) are in the transition stage from ULIRGs to quasi-stellar objects (QSOs). To inspect this...
On the dynamical evolution of hotspots in powerful radio-loud active galactic nuclei (2007)
Kawakatu, Nozomu, Kino, Motoki
We describe the dynamical evolution of hot spots velocity, pressure and mass density in radio loud active galactic nuclei (AGNs), taking proper account of (1) the conservations of the mass, momentum,...
Exploring Supermassive Black Hole Growth with ALMA (2007)
Kawakatu, Nozomu, Andreani, Paola, Granato, Gian Luigi, Danese, Luigi
Massive tori with ≈ 108−9M⊙ are predicted to extend on ∼100 pc scale around the centre of elliptical galaxy progenitors by a model of a supermassive black hole (SMBH) growth coeval to the...
Exploring Supermassive Black Hole Growth with ALMA (2007)
Kawakatu, Nozomu, Andreani, Paola, Granato, Gian Luigi, Danese, Luigi
Massive tori with $\approx 10^{8-9}M_{\odot}$ are predicted to extend on $\sim $100 pc scale around the centre of elliptical galaxy progenitors by a model of a supermassive black hole (SMBH) growth...
Kawakatu, Nozomu, Imanishi, Masatoshi, Nagao, Tohru
We discovered a significant anti-correlation between the mass of a supermassive black hole (SMBH), $M_{\rm BH}$, and the luminosity ratio of infrared to active galactic nuclei (AGN) Eddington...
Type I ULIRGs: Transition Stage from ULIRGs to QSOs (2005)
Kawakatu, Nozomu, Anabuki, Naohisa, Nagao, Tohru, Umemura, Masayuki, Nakagawa, Takao
We examine whether the ultraluminous infrared galaxies that contain a type I Seyfert nucleus (a type I ULIRG) are in the transition stage from ULIRGs to quasi-stellar objects (QSOs). To inspect this...
Kawakatu, Nozomu, Saitoh, Takayuki R., Wada, Keiichi
Combining a theoretical model of mass accretion onto a galactic center with a high-resolution $N$-body/SPH simulation, we investigate the formation of an intermediate massive black hole (IMBH) during...
Formation of Massive Black Holes in Globular Clusters (2005)
Kawakatu, Nozomu, Umemura, Masayuki
The hydrodynamic formation of massive black holes (BHs) in globular clusters is considered. In particular, we examine the possibility of the BH formation induced by the radiation drag that is exerted...
QSO Formation under Coevolution of SMBH and Bulge (2005)
Kawakatu, Nozomu, Umemura, Masayuki, Mori, Masao
he formation and growth of supermassive black holes (SMBHs) physically linked with bulges are considered. We focus on the radiation hydrodynamic process for the growth of SMBH in the optically thick...
Why Massive Black Holes are Small in Disk Galxies? (2003)
Kawakatu, Nozomu, Umemura, Masayuki
A potential mechanism is proposed to account for the fact that supermassive black holes (SMBHs) in disk galaxies appear to be smaller than those in elliptical galaxies in the same luminosity range....
Proto-Quasars:Physical States and Observable Properties (2002)
Kawakatu, Nozomu, Umemura, Masayuki, Mori, Masao
Based on the radiation hydrodynamical model for the black hole(BH) growth,incorporated with the chemical evolution of the early-type host galaxy, we construct the coevolution model of a QSO BH and...
Kawakatu, Nozomu, Umemura, Masayuki
We quantitatively scrutinize the effects of the radiation drag arising from the radiation fields in a galactic bulge in order to examine the possibility that the radiation drag could be an effective...