Achievements & Publications

Puzzling outer-density profile of the dark matter halo in the Andromeda galaxy

Image

Kirihara, Takanobu,   Miki, Yohei,   Mori, Masao

The cold dark matter (CDM) cosmology, which is the standard theory of the structure formation in the universe, predicts that the outer density profile of dark matter halos decreases with the cube of distance from the center. However, so far not much effort has been expended in examining this hypothesis....

Multi-dimensional Simulations of the Expanding Supernova Remnant of SN 1987A

Image

Potter, T.~M.,   Staveley-Smith, L.,   Reville, B.,   Ng, C. -Y.,   Bicknell, G.~V.,   Sutherland, R.~S.

The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There is still a large number of outstanding questions, such as the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova...

Jet-intracluster medium interaction in Hydra A - I. Estimates of jet velocity from inner knots

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Nawaz, M.~A.,   Wagner, A.~Y.,   Bicknell, G.~V.,   Sutherland , R.~S.,   McNamara, B.~R.

We present the first stage of an investigation of the interactions of the jets in the radio galaxy Hydra A with the intracluster medium. We consider the jet kinetic power, the galaxy and cluster atmosphere and the inner structure of the radio source. Analysing radio observations of the inner lobes...

Transonic galactic outflows in a dark matter halo with a central black hole and its application to the Sombrero galaxy

Image

Igarashi, Asuka,   Mori, Masao,   Nitta, Shin-ya

We have classified possible transonic solutions of galactic outflows in the gravitational potential of the dark matter halo (DMH) and supermassive black hole (SMBH) under the assumptions of isothermal, spherically symmetric and steady state. It is clarified that the gravity of SMBH adds a new branch of transonic solutions with...

The Core-Cusp Problem in Cold Dark Matter Halos and Supernova Feedback: Effects of Oscillation

Image

Ogiya, Go,   Mori, Masao

This study investigates the dynamical response of dark matter (DM) halos to recurrent starbursts in forming less-massive galaxies to solve the core-cusp problem. The gas, which is heated by supernova feedback after a starburst, expands and the star formation then terminates. This expanding gas loses energy by radiative cooling and...

On the evolution of gas clouds exposed to AGN radiation - I. Three-dimensional radiation hydrodynamic simulations

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Namekata, D.,   Umemura, M.,   Hasegawa, K.

We perform three-dimensional radiation hydrodynamic simulations of uniform dusty gas clouds irradiated by an active galactic nucleus (AGN) to investigate the dependence of evolution of clouds on the ionization parameter \U\ and the Strömgren number \N\_S. We find that the evolution can be classified into two cases depending on \U\....

Relics of Galaxy Merging: Observational Predictions for a Wandering Massive Black Hole and Accompanying Star Cluster in the Halo of M31

Image

Kawaguchi, Toshihiro,   Saito, Yuriko,   Miki, Yohei,   Mori, Masao

Galaxies and massive black holes (BHs) presumably grow via galactic merging events and subsequent BH coalescence. As a case study, we investigate the merging event between the Andromeda galaxy (M31) and a satellite galaxy. We compute the expected observational appearance of the massive BH that was at the center of...

What is the Physical Origin of Strong Ly\ensuremathα Emission? I. Demographics of Ly\ensuremathα Emitter Structures

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Shibuya, Takatoshi,   Ouchi, Masami,   Nakajima, Kimihiko,   Yuma, Suraphong,   Hashimoto, Takuya,   Shimasaku, Kazuhiro

We present the results of structure analyses for a large sample of 426 Ly\ensuremathα emitters (LAEs) at z åisebox-0.5ex~ 2.2 that are observed with the Hubble Space Telescope/Advanced Camera for Surveys and WFC3-IR during deep extra-galactic legacy surveys. We confirm that the merger fraction and the average ellipticity of LAE's...

Image

Puzzling outer-density profile of the dark matter halo in the Andromeda galaxy

Kirihara, Takanobu,   Miki, Yohei,   Mori, Masao

The cold dark matter (CDM) cosmology, which is the standard theory of the structure formation in the universe, predicts that the outer density profile of dark matter halos decreases with the cube of distance from the center. However, so far not much effort has been expended in examining this hypothesis....

December 2014   Publications of the Astronomical Society of Japan
Image

Multi-dimensional Simulations of the Expanding Supernova Remnant of SN 1987A

Potter, T.~M.,   Staveley-Smith, L.,   Reville, B.,   Ng, C. -Y.,   Bicknell, G.~V.,   Sutherland, R.~S.

The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There is still a large number of outstanding questions, such as the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova...

October 2014   The Astrophysical Journal
Image

Jet-intracluster medium interaction in Hydra A - I. Estimates of jet velocity from inner knots

Nawaz, M.~A.,   Wagner, A.~Y.,   Bicknell, G.~V.,   Sutherland , R.~S.,   McNamara, B.~R.

We present the first stage of an investigation of the interactions of the jets in the radio galaxy Hydra A with the intracluster medium. We consider the jet kinetic power, the galaxy and cluster atmosphere and the inner structure of the radio source. Analysing radio observations of the inner lobes...

October 2014   Monthly Notices of the Royal Astronomical Society
Image

Transonic galactic outflows in a dark matter halo with a central black hole and its application to the Sombrero galaxy

Igarashi, Asuka,   Mori, Masao,   Nitta, Shin-ya

We have classified possible transonic solutions of galactic outflows in the gravitational potential of the dark matter halo (DMH) and supermassive black hole (SMBH) under the assumptions of isothermal, spherically symmetric and steady state. It is clarified that the gravity of SMBH adds a new branch of transonic solutions with...

October 2014   Monthly Notices of the Royal Astronomical Society
Image

The Core-Cusp Problem in Cold Dark Matter Halos and Supernova Feedback: Effects of Oscillation

Ogiya, Go,   Mori, Masao

This study investigates the dynamical response of dark matter (DM) halos to recurrent starbursts in forming less-massive galaxies to solve the core-cusp problem. The gas, which is heated by supernova feedback after a starburst, expands and the star formation then terminates. This expanding gas loses energy by radiative cooling and...

September 2014   The Astrophysical Journal
Image

On the evolution of gas clouds exposed to AGN radiation - I. Three-dimensional radiation hydrodynamic simulations

Namekata, D.,   Umemura, M.,   Hasegawa, K.

We perform three-dimensional radiation hydrodynamic simulations of uniform dusty gas clouds irradiated by an active galactic nucleus (AGN) to investigate the dependence of evolution of clouds on the ionization parameter \U\ and the Strömgren number \N\_S. We find that the evolution can be classified into two cases depending on \U\....

September 2014   Monthly Notices of the Royal Astronomical Society
Image

Relics of Galaxy Merging: Observational Predictions for a Wandering Massive Black Hole and Accompanying Star Cluster in the Halo of M31

Kawaguchi, Toshihiro,   Saito, Yuriko,   Miki, Yohei,   Mori, Masao

Galaxies and massive black holes (BHs) presumably grow via galactic merging events and subsequent BH coalescence. As a case study, we investigate the merging event between the Andromeda galaxy (M31) and a satellite galaxy. We compute the expected observational appearance of the massive BH that was at the center of...

July 2014   The Astrophysical Journal Letters
Image

What is the Physical Origin of Strong Ly\ensuremathα Emission? I. Demographics of Ly\ensuremathα Emitter Structures

Shibuya, Takatoshi,   Ouchi, Masami,   Nakajima, Kimihiko,   Yuma, Suraphong,   Hashimoto, Takuya,   Shimasaku, Kazuhiro

We present the results of structure analyses for a large sample of 426 Ly\ensuremathα emitters (LAEs) at z åisebox-0.5ex~ 2.2 that are observed with the Hubble Space Telescope/Advanced Camera for Surveys and WFC3-IR during deep extra-galactic legacy surveys. We confirm that the merger fraction and the average ellipticity of LAE's...

April 2014   The Astrophysical Journal

Puzzling outer-density profile of the dark matter halo in the Andromeda galaxy

Kirihara, Takanobu,   Miki, Yohei,   Mori, Masao
December 2014   Publications of the Astronomical Society of Japan

Multi-dimensional Simulations of the Expanding Supernova Remnant of SN 1987A

Potter, T.~M.,   Staveley-Smith, L.,   Reville, B.,   Ng, C. -Y.,   Bicknell, G.~V.,   Sutherland, R.~S.
October 2014   The Astrophysical Journal

Jet-intracluster medium interaction in Hydra A - I. Estimates of jet velocity from inner knots

Nawaz, M.~A.,   Wagner, A.~Y.,   Bicknell, G.~V.,   Sutherland , R.~S.,   McNamara, B.~R.
October 2014   Monthly Notices of the Royal Astronomical Society

Transonic galactic outflows in a dark matter halo with a central black hole and its application to the Sombrero galaxy

Igarashi, Asuka,   Mori, Masao,   Nitta, Shin-ya
October 2014   Monthly Notices of the Royal Astronomical Society

The Core-Cusp Problem in Cold Dark Matter Halos and Supernova Feedback: Effects of Oscillation

Ogiya, Go,   Mori, Masao
September 2014   The Astrophysical Journal

On the evolution of gas clouds exposed to AGN radiation - I. Three-dimensional radiation hydrodynamic simulations

Namekata, D.,   Umemura, M.,   Hasegawa, K.
September 2014   Monthly Notices of the Royal Astronomical Society

Relics of Galaxy Merging: Observational Predictions for a Wandering Massive Black Hole and Accompanying Star Cluster in the Halo of M31

Kawaguchi, Toshihiro,   Saito, Yuriko,   Miki, Yohei,   Mori, Masao
July 2014   The Astrophysical Journal Letters

What is the Physical Origin of Strong Ly\ensuremathα Emission? I. Demographics of Ly\ensuremathα Emitter Structures

Shibuya, Takatoshi,   Ouchi, Masami,   Nakajima, Kimihiko,   Yuma, Suraphong,   Hashimoto, Takuya,   Shimasaku, Kazuhiro
April 2014   The Astrophysical Journal