Achievements & Publications

Phantom-GRAPE: Numerical software library to accelerate collisionless N-body simulation with SIMD instruction set on x86 architecture

Image

Tanikawa, Ataru,   Yoshikawa, Kohji,   Nitadori, Keigo,   Okamoto, Takashi

We have developed a numerical software library for collisionless N-body simulations named ``Phantom-GRAPE'' which highly accelerates force calculations among particles by use of a new SIMD instruction set extension to the x86 architecture, Advanced Vector eXtensions (AVX), an enhanced version of the Streaming SIMD Extensions (SSE). In our library, not...

New Class of Very High Energy \ensuremathγ-Ray Emitters: Radio-dark Mini Shells Surrounding Active Galactic Nucleus Jets

Image

Kino, Motoki,   Ito, Hirotaka,   Kawakatu, Nozomu,   Orienti, Monica

We explore non-thermal emission from a shocked interstellar medium, which is identified as an expanding shell, driven by a relativistic jet in active galactic nuclei (AGNs). In this work, we particularly focus on parsec-scale size mini shells surrounding mini radio lobes. From the radio to X-ray band, the mini radio...

Direct Integration of the Collisionless Boltzmann Equation in Six-dimensional Phase Space: Self-gravitating Systems

Image

Yoshikawa, Kohji,   Yoshida, Naoki,   Umemura, Masayuki

We present a scheme for numerical simulations of collisionless self- gravitating systems which directly integrates the Vlasov-Poisson equations in six-dimensional phase space. Using the results from a suite of large-scale numerical simulations, we demonstrate that the present scheme can simulate collisionless self- gravitating systems properly. The integration scheme is based...

Ultrafast Outflows: Galaxy-scale Active Galactic Nucleus Feedback

Image

Wagner, A.~Y.,   Umemura, M.,   Bicknell, G.~V.

We show, using global three-dimensional grid-based hydrodynamical simulations, that ultrafast outflows (UFOs) from active galactic nuclei (AGNs) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy. The AGN wind interacts strongly with the inhomogeneous, two- phase ISM consisting of dense clouds embedded...

A high-resolution study of the X-ray emission and Sunyaev-Zel'dovich effect in the Bullet cluster (1E 0657-56)

Image

Prokhorov, D.~A.,   Million, E.~T.,   Akahori, T.,   Zemcov, M.,   Moraghan, A.,   Nagataki, S.

High-resolution imaging of the Sunyaev-Zel'dovich (SZ) effect opens new possibilities for testing the presence of various high-energy particle populations in clusters of galaxies. A detailed X-ray analysis of the 'Bullet cluster' (1E 0657-56) with Chandra has revealed the presence of additional X-ray spectral components beyond a simple, single-temperature plasma in...

Kiloparsec-scale Radio Structures in Narrow-line Seyfert 1 Galaxies

Image

Doi, Akihiro,   Nagira, Hiroshi,   Kawakatu, Nozomu,   Kino, Motoki,   Nagai, Hiroshi,   Asada, Keiichi

We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from the Faint Images of the Radio Sky at Twenty-centimeters of the Very Large Array, which increases the number of known radio-loud NLS1s with kpc-scale structures to six, including two \ensuremathγ-ray-emitting NLS1s (PMN...

Imaging Simulations of the Sunyaev-Zel'dovich Effect for ALMA

Image

Yamada, Kenkichi,   Kitayama, Tetsu,   Takakuwa, Shigehisa,   Iono, Daisuke,   Tsutsumi, Takahiro,   Kohno, Kotaro

We present imaging simulations of the Sunyaev-Zel'dovich effect of galaxy clusters for the Atacama Large Millimeter/submillimeter Array (ALMA), including the Atacama Compact Array (ACA). In its most compact configuration at 90 GHz, ALMA will resolve the intracluster medium with an effective angular resolution of 5''. It will provide a unique...

Driving Outflows with Relativistic Jets and the Dependence of Active Galactic Nucleus Feedback Efficiency on Interstellar Medium Inhomogeneity

Image

Wagner, A.~Y.,   Bicknell, G.~V.,   Umemura, M.

We examine the detailed physics of the feedback mechanism by relativistic active galactic nucleus (AGN) jets interacting with a two-phase fractal interstellar medium (ISM) in the kpc-scale core of galaxies using 29 three-dimensional grid-based hydrodynamical simulations. The feedback efficiency, as measured by the amount of cloud dispersal generated by the...

ORIGIN: metal creation and evolution from the cosmic dawn

Image

den Herder, Jan-Willem,   Piro, Luigi,   Ohashi, Takaya,   Kouveliotou, Chryssa,   Hartmann, Dieter H.,   Kaastra, Jelle S.

ORIGIN is a proposal for the M3 mission call of ESA aimed at the study of metal creation from the epoch of cosmic dawn. Using high- spectral resolution in the soft X-ray band, ORIGIN will be able to identify the physical conditions of all abundant elements between C and Ni...

Diffuse Ly\ensuremathα haloes around Ly\ensuremathα emitters at z=3: do dark matter distributions determine the Ly\ensuremathα spatial extents?

Image

Matsuda, Y.,   Yamada, T.,   Hayashino, T.,   Yamauchi, R.,   Nakamura, Y.,   Morimoto, N.

Using stacks of Ly\ensuremathα images of 2128 Ly\ensuremathα emitters (LAEs) and 24 proto-cluster UV- selected galaxies (LBGs) at z = 3.1, we examine the surface brightness profiles of Ly\ensuremathα haloes around high-z galaxies as a function of environment and UV luminosity. We find that the slopes of the Ly\ensuremathα radial...

Calorimetry of Active Galactic Nucleus Jets: Testing Plasma Composition in Cygnus A

Image

Kino, M.,   Kawakatu, N.,   Takahara, F.

We examine plasma composition of jets in active galactic nuclei through the comparison of the total pressure (P) with partial pressures of electrons and protons in a cocoon. The total pressure is estimated from the analysis of expanding cocoon dynamics. We determine the average kinetic energy per particle for several...

Investigating Slim Disk Solutions for HLX-1 in ESO 243-49

Image

Godet, O.,   Plazolles, B.,   Kawaguchi, T.,   Lasota, J. -P.,   Barret, D.,   Farrell, S.~A.

The hyperluminous X-ray source HLX-1 in the galaxy ESO 243-49, currently the best intermediate-mass black hole (BH) candidate, displays spectral transitions similar to those observed in Galactic BH binaries, but with a luminosity 100-1000 times higher. We investigated the X-ray properties of this unique source by fitting multi-epoch data collected...

Profiles of Ly\ensuremathα Emission Lines of the Emitters at z = 3.1

Image

Yamada, T.,   Matsuda, Y.,   Kousai, K.,   Hayashino, T.,   Morimoto, N.,   Umemura, M.

We present the results of the observations of the Ly\ensuremathα line profiles of 91 emission-line galaxies at z = 3.1 with a spectral resolution of \ensuremath\ lambda/\ensuremathδ\ensuremathłambda(FWHM) \ensuremath≈1700 or 180 km s$^-1$. A significant fraction of åisebox-0.5ex~50% of the observed objects show the characteristic double peaks in their Ly\ensuremathα profile....

Panoramic Survey of Ly\ensuremathα Emitters at z = 3.1

Image

Yamada, T.,   Nakamura, Y.,   Matsuda, Y.,   Hayashino, T.,   Yamauchi, R.,   Morimoto, N.

We present the results of the extensive narrowband survey of Ly\ensuremathα emission-line objects at z = 3.1 in the 1.38 deg$^2$ area surrounding the high-density region of star- forming galaxies at z = 3.09 in the SSA22 field, as well as in the 1.04 deg$^2$ area of the three separated...

Image

Phantom-GRAPE: Numerical software library to accelerate collisionless N-body simulation with SIMD instruction set on x86 architecture

Tanikawa, Ataru,   Yoshikawa, Kohji,   Nitadori, Keigo,   Okamoto, Takashi

We have developed a numerical software library for collisionless N-body simulations named ``Phantom-GRAPE'' which highly accelerates force calculations among particles by use of a new SIMD instruction set extension to the x86 architecture, Advanced Vector eXtensions (AVX), an enhanced version of the Streaming SIMD Extensions (SSE). In our library, not...

February 2013   New Astronomy
Image

New Class of Very High Energy \ensuremathγ-Ray Emitters: Radio-dark Mini Shells Surrounding Active Galactic Nucleus Jets

Kino, Motoki,   Ito, Hirotaka,   Kawakatu, Nozomu,   Orienti, Monica

We explore non-thermal emission from a shocked interstellar medium, which is identified as an expanding shell, driven by a relativistic jet in active galactic nuclei (AGNs). In this work, we particularly focus on parsec-scale size mini shells surrounding mini radio lobes. From the radio to X-ray band, the mini radio...

February 2013   The Astrophysical Journal
Image

Direct Integration of the Collisionless Boltzmann Equation in Six-dimensional Phase Space: Self-gravitating Systems

Yoshikawa, Kohji,   Yoshida, Naoki,   Umemura, Masayuki

We present a scheme for numerical simulations of collisionless self- gravitating systems which directly integrates the Vlasov-Poisson equations in six-dimensional phase space. Using the results from a suite of large-scale numerical simulations, we demonstrate that the present scheme can simulate collisionless self- gravitating systems properly. The integration scheme is based...

January 2013   The Astrophysical Journal
Image

Ultrafast Outflows: Galaxy-scale Active Galactic Nucleus Feedback

Wagner, A.~Y.,   Umemura, M.,   Bicknell, G.~V.

We show, using global three-dimensional grid-based hydrodynamical simulations, that ultrafast outflows (UFOs) from active galactic nuclei (AGNs) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy. The AGN wind interacts strongly with the inhomogeneous, two- phase ISM consisting of dense clouds embedded...

January 2013   The Astrophysical Journal Letters
Image

A high-resolution study of the X-ray emission and Sunyaev-Zel'dovich effect in the Bullet cluster (1E 0657-56)

Prokhorov, D.~A.,   Million, E.~T.,   Akahori, T.,   Zemcov, M.,   Moraghan, A.,   Nagataki, S.

High-resolution imaging of the Sunyaev-Zel'dovich (SZ) effect opens new possibilities for testing the presence of various high-energy particle populations in clusters of galaxies. A detailed X-ray analysis of the 'Bullet cluster' (1E 0657-56) with Chandra has revealed the presence of additional X-ray spectral components beyond a simple, single-temperature plasma in...

November 2012   Monthly Notices of the Royal Astronomical Society
Image

Kiloparsec-scale Radio Structures in Narrow-line Seyfert 1 Galaxies

Doi, Akihiro,   Nagira, Hiroshi,   Kawakatu, Nozomu,   Kino, Motoki,   Nagai, Hiroshi,   Asada, Keiichi

We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from the Faint Images of the Radio Sky at Twenty-centimeters of the Very Large Array, which increases the number of known radio-loud NLS1s with kpc-scale structures to six, including two \ensuremathγ-ray-emitting NLS1s (PMN...

November 2012   The Astrophysical Journal
Image

Imaging Simulations of the Sunyaev-Zel'dovich Effect for ALMA

Yamada, Kenkichi,   Kitayama, Tetsu,   Takakuwa, Shigehisa,   Iono, Daisuke,   Tsutsumi, Takahiro,   Kohno, Kotaro

We present imaging simulations of the Sunyaev-Zel'dovich effect of galaxy clusters for the Atacama Large Millimeter/submillimeter Array (ALMA), including the Atacama Compact Array (ACA). In its most compact configuration at 90 GHz, ALMA will resolve the intracluster medium with an effective angular resolution of 5''. It will provide a unique...

October 2012   Publications of the Astronomical Society of Japan
Image

Driving Outflows with Relativistic Jets and the Dependence of Active Galactic Nucleus Feedback Efficiency on Interstellar Medium Inhomogeneity

Wagner, A.~Y.,   Bicknell, G.~V.,   Umemura, M.

We examine the detailed physics of the feedback mechanism by relativistic active galactic nucleus (AGN) jets interacting with a two-phase fractal interstellar medium (ISM) in the kpc-scale core of galaxies using 29 three-dimensional grid-based hydrodynamical simulations. The feedback efficiency, as measured by the amount of cloud dispersal generated by the...

October 2012   The Astrophysical Journal
Image

ORIGIN: metal creation and evolution from the cosmic dawn

den Herder, Jan-Willem,   Piro, Luigi,   Ohashi, Takaya,   Kouveliotou, Chryssa,   Hartmann, Dieter H.,   Kaastra, Jelle S.

ORIGIN is a proposal for the M3 mission call of ESA aimed at the study of metal creation from the epoch of cosmic dawn. Using high- spectral resolution in the soft X-ray band, ORIGIN will be able to identify the physical conditions of all abundant elements between C and Ni...

October 2012  
Image

Diffuse Ly\ensuremathα haloes around Ly\ensuremathα emitters at z=3: do dark matter distributions determine the Ly\ensuremathα spatial extents?

Matsuda, Y.,   Yamada, T.,   Hayashino, T.,   Yamauchi, R.,   Nakamura, Y.,   Morimoto, N.

Using stacks of Ly\ensuremathα images of 2128 Ly\ensuremathα emitters (LAEs) and 24 proto-cluster UV- selected galaxies (LBGs) at z = 3.1, we examine the surface brightness profiles of Ly\ensuremathα haloes around high-z galaxies as a function of environment and UV luminosity. We find that the slopes of the Ly\ensuremathα radial...

September 2012   Monthly Notices of the Royal Astronomical Society
Image

Calorimetry of Active Galactic Nucleus Jets: Testing Plasma Composition in Cygnus A

Kino, M.,   Kawakatu, N.,   Takahara, F.

We examine plasma composition of jets in active galactic nuclei through the comparison of the total pressure (P) with partial pressures of electrons and protons in a cocoon. The total pressure is estimated from the analysis of expanding cocoon dynamics. We determine the average kinetic energy per particle for several...

June 2012   The Astrophysical Journal
Image

Investigating Slim Disk Solutions for HLX-1 in ESO 243-49

Godet, O.,   Plazolles, B.,   Kawaguchi, T.,   Lasota, J. -P.,   Barret, D.,   Farrell, S.~A.

The hyperluminous X-ray source HLX-1 in the galaxy ESO 243-49, currently the best intermediate-mass black hole (BH) candidate, displays spectral transitions similar to those observed in Galactic BH binaries, but with a luminosity 100-1000 times higher. We investigated the X-ray properties of this unique source by fitting multi-epoch data collected...

June 2012   The Astrophysical Journal
Image

Profiles of Ly\ensuremathα Emission Lines of the Emitters at z = 3.1

Yamada, T.,   Matsuda, Y.,   Kousai, K.,   Hayashino, T.,   Morimoto, N.,   Umemura, M.

We present the results of the observations of the Ly\ensuremathα line profiles of 91 emission-line galaxies at z = 3.1 with a spectral resolution of \ensuremath\ lambda/\ensuremathδ\ensuremathłambda(FWHM) \ensuremath≈1700 or 180 km s$^-1$. A significant fraction of åisebox-0.5ex~50% of the observed objects show the characteristic double peaks in their Ly\ensuremathα profile....

May 2012   The Astrophysical Journal
Image

Panoramic Survey of Ly\ensuremathα Emitters at z = 3.1

Yamada, T.,   Nakamura, Y.,   Matsuda, Y.,   Hayashino, T.,   Yamauchi, R.,   Morimoto, N.

We present the results of the extensive narrowband survey of Ly\ensuremathα emission-line objects at z = 3.1 in the 1.38 deg$^2$ area surrounding the high-density region of star- forming galaxies at z = 3.09 in the SSA22 field, as well as in the 1.04 deg$^2$ area of the three separated...

April 2012   The Astronomical Journal

Phantom-GRAPE: Numerical software library to accelerate collisionless N-body simulation with SIMD instruction set on x86 architecture

Tanikawa, Ataru,   Yoshikawa, Kohji,   Nitadori, Keigo,   Okamoto, Takashi
February 2013   New Astronomy

New Class of Very High Energy \ensuremathγ-Ray Emitters: Radio-dark Mini Shells Surrounding Active Galactic Nucleus Jets

Kino, Motoki,   Ito, Hirotaka,   Kawakatu, Nozomu,   Orienti, Monica
February 2013   The Astrophysical Journal

Direct Integration of the Collisionless Boltzmann Equation in Six-dimensional Phase Space: Self-gravitating Systems

Yoshikawa, Kohji,   Yoshida, Naoki,   Umemura, Masayuki
January 2013   The Astrophysical Journal

Ultrafast Outflows: Galaxy-scale Active Galactic Nucleus Feedback

Wagner, A.~Y.,   Umemura, M.,   Bicknell, G.~V.
January 2013   The Astrophysical Journal Letters

A high-resolution study of the X-ray emission and Sunyaev-Zel'dovich effect in the Bullet cluster (1E 0657-56)

Prokhorov, D.~A.,   Million, E.~T.,   Akahori, T.,   Zemcov, M.,   Moraghan, A.,   Nagataki, S.
November 2012   Monthly Notices of the Royal Astronomical Society

Kiloparsec-scale Radio Structures in Narrow-line Seyfert 1 Galaxies

Doi, Akihiro,   Nagira, Hiroshi,   Kawakatu, Nozomu,   Kino, Motoki,   Nagai, Hiroshi,   Asada, Keiichi
November 2012   The Astrophysical Journal

Imaging Simulations of the Sunyaev-Zel'dovich Effect for ALMA

Yamada, Kenkichi,   Kitayama, Tetsu,   Takakuwa, Shigehisa,   Iono, Daisuke,   Tsutsumi, Takahiro,   Kohno, Kotaro
October 2012   Publications of the Astronomical Society of Japan

Driving Outflows with Relativistic Jets and the Dependence of Active Galactic Nucleus Feedback Efficiency on Interstellar Medium Inhomogeneity

Wagner, A.~Y.,   Bicknell, G.~V.,   Umemura, M.
October 2012   The Astrophysical Journal

ORIGIN: metal creation and evolution from the cosmic dawn

den Herder, Jan-Willem,   Piro, Luigi,   Ohashi, Takaya,   Kouveliotou, Chryssa,   Hartmann, Dieter H.,   Kaastra, Jelle S.
October 2012  

Diffuse Ly\ensuremathα haloes around Ly\ensuremathα emitters at z=3: do dark matter distributions determine the Ly\ensuremathα spatial extents?

Matsuda, Y.,   Yamada, T.,   Hayashino, T.,   Yamauchi, R.,   Nakamura, Y.,   Morimoto, N.
September 2012   Monthly Notices of the Royal Astronomical Society

Calorimetry of Active Galactic Nucleus Jets: Testing Plasma Composition in Cygnus A

Kino, M.,   Kawakatu, N.,   Takahara, F.
June 2012   The Astrophysical Journal

Investigating Slim Disk Solutions for HLX-1 in ESO 243-49

Godet, O.,   Plazolles, B.,   Kawaguchi, T.,   Lasota, J. -P.,   Barret, D.,   Farrell, S.~A.
June 2012   The Astrophysical Journal

Profiles of Ly\ensuremathα Emission Lines of the Emitters at z = 3.1

Yamada, T.,   Matsuda, Y.,   Kousai, K.,   Hayashino, T.,   Morimoto, N.,   Umemura, M.
May 2012   The Astrophysical Journal

Panoramic Survey of Ly\ensuremathα Emitters at z = 3.1

Yamada, T.,   Nakamura, Y.,   Matsuda, Y.,   Hayashino, T.,   Yamauchi, R.,   Morimoto, N.
April 2012   The Astronomical Journal