Theoretical Astrophysics Seminars

42nd Seminar

Computing the Universe: from Intergalactic to Interstellar Medium

Image

Renyue Cen

Princeton University

This talk will highlight some progress made based on our efforts of computing the universe, in order to understand the dynamics of gas in the universe, from intergalactic to interstellar medium. Select observables presented include the cosmic web from redshift zero to z=2-4, and the escape fraction of Lyman continuum...

41st Seminar

Probing dust aggregate structure in protoplanetary disks by millimeter-wave polarization

Image

Ryo Tazaki

University of Tohoku

Dust coagulation in protoplanetary disks is the first step of planetesimal formation. However, a pathway from dust aggregates to planetesimals remains unclear. Both laboratory and numerical studies have so far shown that the structure of a dust aggregate plays important roles in planetesimal formation. However, the aggregate structure has been...

40th Seminar

Radiation hydrodynamical simulations of first-star binaries including radiative feedback

Image

Kazuyuki Sugimura

University of Tohoku

The formation of the first stars after the big bang is one of the most important outstanding problems in modern astrophysics. While recent theoretical studies of the formation of individual first stars revealed the importance of radiative feedback and led to estimates first star the masses of first stars, studies...

39th Seminar

Uncovering the formation of extremely distant galaxies with ALMA

Image

Takuya Hashimoto

Osaka Sangyo University / NAOJ

電波干渉系 ALMA の登場によって、宇宙再電離時代 (宇宙年齢がおそよ2-10億年) にある銀河の研究は新時代を拓いた。サブミリ波帯に赤方偏移した遠赤外の微細構造輝線 ([OIII] 88μm, [CII] 158μm など) を ALMA で観測することで、再電離時代の星形成銀河を分光同定することが可能になったのである (e.g., Inoue et al. 2016, Science)。さらに、このような宇宙初期の時代、既に豊富なダストが存在することも明らかになってきた (e.g., Watson et al. 2015, Nature)。  本発表では、私たちのグループが推進している超遠方銀河の微細構造輝線 (主に [OIII] 88 μm) およびダスト連続光の観測結果を紹介する。まず私たちは、重力レンズ効果によって明るく見えている遠方銀河1天体を観測した。この結果、赤方偏移 z = 9.11 (宇宙年齢 5.5億年) にある [OIII] 88 μm の分光検出に成功した (Hashimoto et al. 2018a, Nature)。これは現在最も遠い輝線天体である。さらに、ハッブル宇宙望遠鏡やスピッツァー宇宙望遠鏡のデータも組み合わせた多波長データ解析から、観測時点よりも過去の星形成の歴史を遡った。この結果、この銀河が星形成を開始したのは z ~ 15 (宇宙年齢2.5億年) の頃だと推定され、宇宙最初期の星形成に知見を得た。次に、z...

38th Seminar

The most rapidly growing black holes: Narrow Line Seyfert 1s across cosmic time

Image

Chris Done

University of Durham

Narrow Line Seyfert 1s (NLS1) are the lowest mass, highest mass accretion rate Active Galactic Nuclei (AGN) in the local Universe, with black hole masses of 1-10 million x Msun, accreting at the Eddington limit or beyond. These properties are similar to those expected for the majority of the first...

37th Seminar

Fragmentation in self-gravitating accretion disks; Influence of binary systems

Image

Jannes Klee

University of Kiehl

Self-gravitation can play a role in protoplanetary- and AGN-disks. If they are massive enough, gravitoturbulence sets in and acts as a strong driver for angular momentum redistribution. Thereby it moves large amounts of gas from the outer parts of the disk to the central object. However, if the disk cools...

36th Seminar

A New Stellar Population in the Bulge, and a new survey

Image

R. Michael Rich

University of California, Los Angeles (UCLA)

By mass, the Galactic bulge is actually dominated by a relatively metal rich bar. This population exhibits relatively rapid rotation that reflects a pattern speed independent of Galactic latitude. We have completed a survey of 955 RR Lyrae stars in the bulge region, and find a remarkable population that does...

35th Seminar

What young stars' infrared variability reveals about protoplanetary disks

Image

Neal Turner

Jet Propulsion Laboratory, Caltech

Young stars' infrared emission shows several puzzling features: variability uncorrelated with visible-light changes, foreground extinction that recurs erratically on weekly timescales, and excesses over the stellar photosphere too large to explain with starlight absorbed and re-emitted by a hydrostatic protostellar disk. I will discuss how each of these features can...

34th Seminar

Density scratches and formation processes of primordial dark matter haloes via dry mergers

Image

Go Ogiya

LMU/MPI

Galaxy collisions and merging is a ubiquitous process in the theory hierarchical galaxy formation。We investigate the effects of galaxy collisions and mergers on the formation and evolution of galaxies using N-body simulations. In this seminar we present two recent results. 1. In the case in which the two colliding systems...

33rd Seminar

The composition of interstellar molecular gas in galaxies

Image

Nanase Harada

Academia Sinica Institute of Astronomy and Astrophysics (ASIAA)

The molecular composition in star-forming regions in the Milky Way is useful, for example, for determining the current stage of star-formation of a system. In starburst galaxies and active galactic nuclei (AGN), the molecular composition is thought to vary strongly. In the past few years, ALMA observations of multiple species...

31st Seminar (Part 1)

Dancing in the dark: galactic properties trace spin swings along the cosmic web

Image

Yohan Dubois

IAP

A large-scale hydrodynamical cosmological simulation, Horizon-AGN , is used to investigate the alignment between the spin of galaxies and the large-scale cosmic filaments above redshift z = 1.2. The analysis of more than 150 000 galaxies per time step in the redshift range 1.2 &less; z &less; 1.8, resolved with...

31st Seminar (Part 2)

Exploring the Role of AGN Feedback in Galaxy Formation

Image

Rebekka Bieri

IAP

Feedback from active galactic nuclei (AGN) is routinely included in semi-analytic and numerical simulations, which have shown that such feedback is able to quench cooling flows and decrease star formation. Radio-mode feedback models from AGN jets are, however, still in the early stages of development. The impact of the jet...

30th Seminar

The Epoch of Reionization: observations and simulations

Image

Benoît Semelin

LERMA, Observatoire de Paris

I will first briefly review the current observationnal constraints on the Epoch of Reionization, then I will describe the basic physics of reionization and emission of the 21 cm signal. I will then describe the current status and future prospects of 21cm observations and finally I will present modeling techniques...

29th Seminar

A Dynamically Collapsing Cloud Core and a Precursor of a Core in a Filament Supported by Turbulent and Magnetic Pressures

Image

Rei Furuya

Tokushima University

To understand the formation of molecular cores, the eventual sites of star formation, it is not enough to know only the physical state of the star-forming high-density gas. One must also determine the velocity field and density structure of the more diffuse medium surrounding the dense gas. One can go...

28th Seminar

Watching a Little Gas Cloud on its Way into the Galactic Supermassive Black Hole

Image

Andreas Burkert

Ludwig Maximilians Universität München

The Galactic center is one of the most fascinating and extreme places in the Galaxy. Harboring a supermassive black hole with a mass of order 4 million solar masses it experiences cycles of activity and star formation, separated by periods of quiescence that last of order a million years. The...

27th Seminar (Part 1)

Puzzling Features of Quasar Accretion

Image

Charles Steinhardt

Kavli IPMU

The development of virial mass estimates for the central black hole using one quasar spectrum has allowed a dramatic improvement in our understanding of supermassive black hole evolution. I will describe several new puzzles arising from the combination of virial masses with luminosity and redshift measurements, many of which are...

27th Seminar (Part 3)

The Evolution of Star-Forming Galaxies Over Cosmic Time

Image

Josh Speagle

Harvard University, Kavli IPMU

The assembly and evolution of galaxies over cosmic time is a complex process. Historically, galaxy evolution was thought to be governed by mainlystochastic, potentially divergent processes such as major mergers, whichwere linked to active galactic nuclei (AGN) activity and vigorous starformation followed by a rapid "quenching" process. In the last...

27th Seminar (Part 2)

How Does Galaxy Environment Influence AGN Activity?

Image

Emil Khabiboulline

Caltech, Kavli IPMU

The development of virial mass estimates for the central black hole using one quasar spectrum has allowed a dramatic improvement in our understanding of supermassive black hole evolution. I will describe several new puzzles arising from the combination of virial masses with luminosity and redshift measurements, many of which are...

26th Seminar

Relativistic Jets and Black Hole Accretion Disks

Image

Geoffrey Bicknell

The Australian National University

Since about 2005 our group at the ANU, in collaboration with Alex Wagner, has been conducting fundamental research on the interaction of jets with the interstellar medium of evolving galaxies. One area of research involves the interaction of relativistic jets with an inhomogeneous interstellar medium consisting of dense clouds. This...

25th Seminar

1. The effects of Chern-Simons Gravity and Electromagnetic fields in Blach Hole space-time 2. Space-time rotation induced Landau quantization

Image

Takahashi Rohta

Tomakomai National College of Technology

1. One of the goals of galactic center black hole observations is the validation of theories of gravity. In addition, recent radio observations have revealed visibility and positional information of light source, and in hte near future we will obtain interferometer observations that will show how the magnetic radiation plasma...

24th Seminar

Are Lyman alpha emitters the building blocks of the Milky Way?

Image

Hidenobu Yajima

Pennsylvania State University

Strong Lyman alpha emitting galaxies have been observed in large numbers over a wide range in redshift. Such galaxies are called Lyman alpha emitters (LAEs), and they are thought to be galaxies in the early stages of evolution. However, there are still many open questions regarding their formation and evolution....

23rd Seminar

The AGN/Starburst connection at z~2 from an IR/submillimeter point of view

Image

Laurie Riguccini

Ehime University

It is well known nowadays that most of the mass assembly occurs at z~1-3. However, a non-negligible fraction of the star formation across cosmic time occurred within dust-enshrouded environments. One important question is therefore whether we really know the exact amount of star formation activity, which could be strongly biased...

22nd Seminar

The effect of photo-dissociation in the mass accretion phase of PopIII.1 stars

Image

Hajime Susa

Konan University

Studies throughout the past decade indicate that the mass of the first generation of stars was extremely large, unlike most stars in our galaxy. However, according to recent work on the mass accretion phase, the gas is likely to fragment and produce a cluster of stars, rather than accreting smoothly...

21st Seminar

The formation of the first stars and galaxies

Image

Thomas Greif

Max Planck Institut für Astrophysik

One of the final frontiers in modern cosmology is the formation of the first stars and galaxies at the end of the cosmic dark ages, when the Universe transitioned from its simple initial state to one of ever increasing complexity. I will discuss how the first bound gas clouds condensed...

20th Seminar (Part 2)

Modeling the Electromagnetic Signature of Merging Supermassive Black Holes

Image

Takamitsu Tanaka

Max Planck Institut für Astrophysik

Recently, intense attention has focused on the possibility that merging supermassive black hole binaries could be observed with both electromagnetic and gravitational waves. Such multi-messenger studies would (i) probe dark energy out to z~10, and (ii) allow follow-up studies of active galactic nuclei with central engines whose masses and spins...

20th Seminar (Part 1)

A Road to Supermassive Black Hole Merger

Image

Kimitake Hayasaki

Kyoto University

Hierarchical structure formation hypothesis inevitably leads to the formation of binary supermassive black holes (SMBHs) on a subparsec scale in merged galactic nuclei. However, to date there has been no unambiguous detection of such systems. In this talk, I propose how binary SMBHs merge and a feasible method to detect...

19th Seminar

Relativistic Jet Feedback in Evolving Galaxies

Image

Alexander Wagner

The Australian National University

In the formation process of galaxies, AGN jets are thought to have the important function of feeding energy and momentum back into the halo of the host galaxies and dispersing the gas within. The set of 14 realistic 3-D simulations that we have recently performed quantitatively demonstrate the efficiency of...

18th Seminar

Massive stars in galaxies: their Feedback over their Lives

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Gerhardt Hensler

University of Vienna

Although only small by number massive stars influence the evolution of galaxies most efficiently. Their short lifetimes in combination with enormous amounts of power by radiative and kinetic energy and furthermore the release of substantial fractions of heavy elements make them the most important drivers of the thermal and chemical...

17th Seminar

The Chemo-dynamical Treatment of Galaxy Evolution

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Gerhardt Hensler

University of Vienna

Because of various components, different gas phases and stars, their mutual interactions, and largely varying timescales galaxies represent highly complex systems. Competing but also counteracting processes occur that depend on the physical state of a region and its location in the galaxy and which are theoretically and empirically elaborated. Evolutionary...

16th Seminar

Physics and Fluid-Dynamical Simulations Using GPUs

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Muranushi Takayuki

University of Kyoto

GPUを練習するための簡単化した重力N体計算・分子動力学計算・宇宙線加速などの計算。またそれを行うための,約10ノードのGPUクラスタ型計算機の構築。 原子惑星系円盤環境下での,氷ダストの帯電量や放電現象を見積もるためのパラメータ・サーベイ 星間水素原子ガスの熱的不安定性の研究(マルチGPU環境で動作するFull Godunov流体コードを作成と,長崎大学DEGIMA,東京工業大学TSUBAMEの大規模GPUクラスタへの実装。) ...

15th Seminar

Numerical Simulations of High-energy Phenomena in the Universe

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Shigehiro Nagataki

Yukawa Institute for Theoretical Physics, Kyoto University

宇宙では謎に満ちた様々な高エネルギー天体現象が観測されています。 今回のセミナーでは,スーパーコンピュータ─の発展により,数値シ ミュレーションによって高エネルギー天体の理解が大きく進んでいる ことを紹介したいと思います。高エネルギー天体現象の少なからずが 非熱平衡にある系の現象である一方で,従来の数値シミュレーション では熱平衡を仮定した計算が行われていることが少なくありませんで した。それ故,高エネルギー天体現象と数値シミュレーションは必ず しも相性の良いものではないと言えるかもしれません...

42nd Seminar

Image

Computing the Universe: from Intergalactic to Interstellar Medium

Renyue Cen

Princeton University

This talk will highlight some progress made based on our efforts of computing the universe, in order to understand the dynamics of gas in the universe, from intergalactic to interstellar medium. Select observables presented include the cosmic web from redshift zero to z=2-4, and the escape fraction of Lyman continuum...

June 2019   13 : 30     computational fluid dynamics, galaxy evolution, and cosmological simulations
41st Seminar

Image

Probing dust aggregate structure in protoplanetary disks by millimeter-wave polarization

Ryo Tazaki

University of Tohoku

Dust coagulation in protoplanetary disks is the first step of planetesimal formation. However, a pathway from dust aggregates to planetesimals remains unclear. Both laboratory and numerical studies have so far shown that the structure of a dust aggregate plays important roles in planetesimal formation. However, the aggregate structure has been...

May 2019   13 : 30     dust and protoplanetary discs
40th Seminar

Image

Radiation hydrodynamical simulations of first-star binaries including radiative feedback

Kazuyuki Sugimura

University of Tohoku

The formation of the first stars after the big bang is one of the most important outstanding problems in modern astrophysics. While recent theoretical studies of the formation of individual first stars revealed the importance of radiative feedback and led to estimates first star the masses of first stars, studies...

February 2019   15 : 15     numerical simulations, radiative transfer, and first stars
39th Seminar

Image

Uncovering the formation of extremely distant galaxies with ALMA

Takuya Hashimoto

Osaka Sangyo University / NAOJ

電波干渉系 ALMA の登場によって、宇宙再電離時代 (宇宙年齢がおそよ2-10億年) にある銀河の研究は新時代を拓いた。サブミリ波帯に赤方偏移した遠赤外の微細構造輝線 ([OIII] 88μm, [CII] 158μm など) を ALMA で観測することで、再電離時代の星形成銀河を分光同定することが可能になったのである (e.g., Inoue et al. 2016, Science)。さらに、このような宇宙初期の時代、既に豊富なダストが存在することも明らかになってきた (e.g., Watson et al. 2015, Nature)。  本発表では、私たちのグループが推進している超遠方銀河の微細構造輝線 (主に [OIII] 88 μm) およびダスト連続光の観測結果を紹介する。まず私たちは、重力レンズ効果によって明るく見えている遠方銀河1天体を観測した。この結果、赤方偏移 z = 9.11 (宇宙年齢 5.5億年) にある [OIII] 88 μm の分光検出に成功した (Hashimoto et al. 2018a, Nature)。これは現在最も遠い輝線天体である。さらに、ハッブル宇宙望遠鏡やスピッツァー宇宙望遠鏡のデータも組み合わせた多波長データ解析から、観測時点よりも過去の星形成の歴史を遡った。この結果、この銀河が星形成を開始したのは z ~ 15 (宇宙年齢2.5億年) の頃だと推定され、宇宙最初期の星形成に知見を得た。次に、z...

October 2018   13 : 30     reionization, ALMA, first galaxies, and first stars
38th Seminar

Image

The most rapidly growing black holes: Narrow Line Seyfert 1s across cosmic time

Chris Done

University of Durham

Narrow Line Seyfert 1s (NLS1) are the lowest mass, highest mass accretion rate Active Galactic Nuclei (AGN) in the local Universe, with black hole masses of 1-10 million x Msun, accreting at the Eddington limit or beyond. These properties are similar to those expected for the majority of the first...

September 2018   13 : 30     seyfert galaxies, NLS1, AGN, and black holes
37th Seminar

Image

Fragmentation in self-gravitating accretion disks; Influence of binary systems

Jannes Klee

University of Kiehl

Self-gravitation can play a role in protoplanetary- and AGN-disks. If they are massive enough, gravitoturbulence sets in and acts as a strong driver for angular momentum redistribution. Thereby it moves large amounts of gas from the outer parts of the disk to the central object. However, if the disk cools...

August 2018   13 : 30     accretion discs, computational fluid dynamics, and numerical simulations
36th Seminar

Image

A New Stellar Population in the Bulge, and a new survey

R. Michael Rich

University of California, Los Angeles (UCLA)

By mass, the Galactic bulge is actually dominated by a relatively metal rich bar. This population exhibits relatively rapid rotation that reflects a pattern speed independent of Galactic latitude. We have completed a survey of 955 RR Lyrae stars in the bulge region, and find a remarkable population that does...

March 2016   10 : 30     galaxy formation and observations
35th Seminar

Image

What young stars' infrared variability reveals about protoplanetary disks

Neal Turner

Jet Propulsion Laboratory, Caltech

Young stars' infrared emission shows several puzzling features: variability uncorrelated with visible-light changes, foreground extinction that recurs erratically on weekly timescales, and excesses over the stellar photosphere too large to explain with starlight absorbed and re-emitted by a hydrostatic protostellar disk. I will discuss how each of these features can...

October 2015   15 : 30     protoplanetary discs and MHD
34th Seminar

Image

Density scratches and formation processes of primordial dark matter haloes via dry mergers

Go Ogiya

LMU/MPI

Galaxy collisions and merging is a ubiquitous process in the theory hierarchical galaxy formation。We investigate the effects of galaxy collisions and mergers on the formation and evolution of galaxies using N-body simulations. In this seminar we present two recent results. 1. In the case in which the two colliding systems...

October 2015   13 : 30     DM Halo, N-body simulation, and structure formation
33rd Seminar

Image

The composition of interstellar molecular gas in galaxies

Nanase Harada

Academia Sinica Institute of Astronomy and Astrophysics (ASIAA)

The molecular composition in star-forming regions in the Milky Way is useful, for example, for determining the current stage of star-formation of a system. In starburst galaxies and active galactic nuclei (AGN), the molecular composition is thought to vary strongly. In the past few years, ALMA observations of multiple species...

September 2015   13 : 00     ULIRG, IR, radiative transfer, and protostellar disc
32nd Seminar

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Radiation transport calculation of the thermal radiation from gamma-ray burst jets

Sanshiro Shibata

Konan University

Gamma-ray bursts (GRB) are the one of the most energetic phenomena in the universe, with typically 1051 erg in gamma rays emitted within of order few tens of seconds. In the case long gamma-ray burst, the radiation is emitted from relativistic jets launched as a result of the gravitational collapse...

March 2015   13 : 30     GRB
31st Seminar (Part 1)

Image

Dancing in the dark: galactic properties trace spin swings along the cosmic web

Yohan Dubois

IAP

A large-scale hydrodynamical cosmological simulation, Horizon-AGN , is used to investigate the alignment between the spin of galaxies and the large-scale cosmic filaments above redshift z = 1.2. The analysis of more than 150 000 galaxies per time step in the redshift range 1.2 &less; z &less; 1.8, resolved with...

October 2014   13 : 30     SMBH and galaxy formation
31st Seminar (Part 2)

Image

Exploring the Role of AGN Feedback in Galaxy Formation

Rebekka Bieri

IAP

Feedback from active galactic nuclei (AGN) is routinely included in semi-analytic and numerical simulations, which have shown that such feedback is able to quench cooling flows and decrease star formation. Radio-mode feedback models from AGN jets are, however, still in the early stages of development. The impact of the jet...

October 2014   14 : 30     AGN feedback and galaxy evolution
30th Seminar

Image

The Epoch of Reionization: observations and simulations

Benoît Semelin

LERMA, Observatoire de Paris

I will first briefly review the current observationnal constraints on the Epoch of Reionization, then I will describe the basic physics of reionization and emission of the 21 cm signal. I will then describe the current status and future prospects of 21cm observations and finally I will present modeling techniques...

September 2014   13 : 30     reionization
29th Seminar

Image

A Dynamically Collapsing Cloud Core and a Precursor of a Core in a Filament Supported by Turbulent and Magnetic Pressures

Rei Furuya

Tokushima University

To understand the formation of molecular cores, the eventual sites of star formation, it is not enough to know only the physical state of the star-forming high-density gas. One must also determine the velocity field and density structure of the more diffuse medium surrounding the dense gas. One can go...

July 2014   13 : 30     GMC, turbulence, MHD, star formation, molecular cores, and observations
28th Seminar

Image

Watching a Little Gas Cloud on its Way into the Galactic Supermassive Black Hole

Andreas Burkert

Ludwig Maximilians Universität München

The Galactic center is one of the most fascinating and extreme places in the Galaxy. Harboring a supermassive black hole with a mass of order 4 million solar masses it experiences cycles of activity and star formation, separated by periods of quiescence that last of order a million years. The...

February 2014   17 : 00     hydrodynamics, G2, clouds, Galactic center, SMBH, AGN, and accretion discs
27th Seminar (Part 1)

Image

Puzzling Features of Quasar Accretion

Charles Steinhardt

Kavli IPMU

The development of virial mass estimates for the central black hole using one quasar spectrum has allowed a dramatic improvement in our understanding of supermassive black hole evolution. I will describe several new puzzles arising from the combination of virial masses with luminosity and redshift measurements, many of which are...

August 2013   15 : 00     quasars, SMBH, and AGN
27th Seminar (Part 3)

Image

The Evolution of Star-Forming Galaxies Over Cosmic Time

Josh Speagle

Harvard University, Kavli IPMU

The assembly and evolution of galaxies over cosmic time is a complex process. Historically, galaxy evolution was thought to be governed by mainlystochastic, potentially divergent processes such as major mergers, whichwere linked to active galactic nuclei (AGN) activity and vigorous starformation followed by a rapid "quenching" process. In the last...

August 2013   16 : 20     quasars, SMBH, and AGN
27th Seminar (Part 2)

Image

How Does Galaxy Environment Influence AGN Activity?

Emil Khabiboulline

Caltech, Kavli IPMU

The development of virial mass estimates for the central black hole using one quasar spectrum has allowed a dramatic improvement in our understanding of supermassive black hole evolution. I will describe several new puzzles arising from the combination of virial masses with luminosity and redshift measurements, many of which are...

August 2013   15 : 40     quasars, SMBH, and AGN
26th Seminar

Image

Relativistic Jets and Black Hole Accretion Disks

Geoffrey Bicknell

The Australian National University

Since about 2005 our group at the ANU, in collaboration with Alex Wagner, has been conducting fundamental research on the interaction of jets with the interstellar medium of evolving galaxies. One area of research involves the interaction of relativistic jets with an inhomogeneous interstellar medium consisting of dense clouds. This...

July 2013   14 : 00     AGN, AGN feedback, AGN jets, SMBH, M-sigma relation, MHD, accretion discs, radio galaxies, and Hydra A
25th Seminar

Image

1. The effects of Chern-Simons Gravity and Electromagnetic fields in Blach Hole space-time 2. Space-time rotation induced Landau quantization

Takahashi Rohta

Tomakomai National College of Technology

1. One of the goals of galactic center black hole observations is the validation of theories of gravity. In addition, recent radio observations have revealed visibility and positional information of light source, and in hte near future we will obtain interferometer observations that will show how the magnetic radiation plasma...

March 2012   13 : 30     black holes, general relativity, and radiative transfer
24th Seminar

Image

Are Lyman alpha emitters the building blocks of the Milky Way?

Hidenobu Yajima

Pennsylvania State University

Strong Lyman alpha emitting galaxies have been observed in large numbers over a wide range in redshift. Such galaxies are called Lyman alpha emitters (LAEs), and they are thought to be galaxies in the early stages of evolution. However, there are still many open questions regarding their formation and evolution....

March 2012   13 : 30     LAE, cosmology, radiative transfer, and Milky Way
23rd Seminar

Image

The AGN/Starburst connection at z~2 from an IR/submillimeter point of view

Laurie Riguccini

Ehime University

It is well known nowadays that most of the mass assembly occurs at z~1-3. However, a non-negligible fraction of the star formation across cosmic time occurred within dust-enshrouded environments. One important question is therefore whether we really know the exact amount of star formation activity, which could be strongly biased...

February 2012   13 : 30     AGN, starbursts, high-z galaxies, galaxy formation, IR, and submm
22nd Seminar

Image

The effect of photo-dissociation in the mass accretion phase of PopIII.1 stars

Hajime Susa

Konan University

Studies throughout the past decade indicate that the mass of the first generation of stars was extremely large, unlike most stars in our galaxy. However, according to recent work on the mass accretion phase, the gas is likely to fragment and produce a cluster of stars, rather than accreting smoothly...

December 2011   13 : 30     PopIII stars, accretion discs, radiative feedback, and star formation
21st Seminar

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The formation of the first stars and galaxies

Thomas Greif

Max Planck Institut für Astrophysik

One of the final frontiers in modern cosmology is the formation of the first stars and galaxies at the end of the cosmic dark ages, when the Universe transitioned from its simple initial state to one of ever increasing complexity. I will discuss how the first bound gas clouds condensed...

September 2011   15 : 00     first stars and first galaxies
20th Seminar (Part 2)

Image

Modeling the Electromagnetic Signature of Merging Supermassive Black Holes

Takamitsu Tanaka

Max Planck Institut für Astrophysik

Recently, intense attention has focused on the possibility that merging supermassive black hole binaries could be observed with both electromagnetic and gravitational waves. Such multi-messenger studies would (i) probe dark energy out to z~10, and (ii) allow follow-up studies of active galactic nuclei with central engines whose masses and spins...

August 2011   15 : 00     SMBH, SMBH mergers, and accretion discs
20th Seminar (Part 1)

Image

A Road to Supermassive Black Hole Merger

Kimitake Hayasaki

Kyoto University

Hierarchical structure formation hypothesis inevitably leads to the formation of binary supermassive black holes (SMBHs) on a subparsec scale in merged galactic nuclei. However, to date there has been no unambiguous detection of such systems. In this talk, I propose how binary SMBHs merge and a feasible method to detect...

August 2011   15 : 00     SMBH, SMBH mergers, accretion discs, SPH, and X-rays
19th Seminar

Relativistic Jet Feedback in Evolving Galaxies

Alexander Wagner

The Australian National University

In the formation process of galaxies, AGN jets are thought to have the important function of feeding energy and momentum back into the halo of the host galaxies and dispersing the gas within. The set of 14 realistic 3-D simulations that we have recently performed quantitatively demonstrate the efficiency of...

October 2010   15 : 00     AGN jets, AGN feedback, galaxy formation, m-sigma relation, and hydrodynamics
18th Seminar

Massive stars in galaxies: their Feedback over their Lives

Gerhardt Hensler

University of Vienna

Although only small by number massive stars influence the evolution of galaxies most efficiently. Their short lifetimes in combination with enormous amounts of power by radiative and kinetic energy and furthermore the release of substantial fractions of heavy elements make them the most important drivers of the thermal and chemical...

September 2010   15 : 00     massive stars and supernovae
17th Seminar

The Chemo-dynamical Treatment of Galaxy Evolution

Gerhardt Hensler

University of Vienna

Because of various components, different gas phases and stars, their mutual interactions, and largely varying timescales galaxies represent highly complex systems. Competing but also counteracting processes occur that depend on the physical state of a region and its location in the galaxy and which are theoretically and empirically elaborated. Evolutionary...

September 2010   15 : 00     chemodynamics, massive stars, and supernovae
16th Seminar

Physics and Fluid-Dynamical Simulations Using GPUs

Muranushi Takayuki

University of Kyoto

GPUを練習するための簡単化した重力N体計算・分子動力学計算・宇宙線加速などの計算。またそれを行うための,約10ノードのGPUクラスタ型計算機の構築。 原子惑星系円盤環境下での,氷ダストの帯電量や放電現象を見積もるためのパラメータ・サーベイ 星間水素原子ガスの熱的不安定性の研究(マルチGPU環境で動作するFull Godunov流体コードを作成と,長崎大学DEGIMA,東京工業大学TSUBAMEの大規模GPUクラスタへの実装。) ...

July 2010   15 : 00     GPU and hydrodynamics
15th Seminar

Numerical Simulations of High-energy Phenomena in the Universe

Shigehiro Nagataki

Yukawa Institute for Theoretical Physics, Kyoto University

宇宙では謎に満ちた様々な高エネルギー天体現象が観測されています。 今回のセミナーでは,スーパーコンピュータ─の発展により,数値シ ミュレーションによって高エネルギー天体の理解が大きく進んでいる ことを紹介したいと思います。高エネルギー天体現象の少なからずが 非熱平衡にある系の現象である一方で,従来の数値シミュレーション では熱平衡を仮定した計算が行われていることが少なくありませんで した。それ故,高エネルギー天体現象と数値シミュレーションは必ず しも相性の良いものではないと言えるかもしれません...

June 2010   15 : 00     high-energy astrophysics

42nd Seminar Computing the Universe: from Intergalactic to Interstellar Medium

Renyue Cen (Princeton University)
June 2019   13 : 30     computational fluid dynamics, galaxy evolution, and cosmological simulations

41st Seminar Probing dust aggregate structure in protoplanetary disks by millimeter-wave polarization

Ryo Tazaki (University of Tohoku)
May 2019   13 : 30     dust and protoplanetary discs

40th Seminar Radiation hydrodynamical simulations of first-star binaries including radiative feedback

Kazuyuki Sugimura (University of Tohoku)
February 2019   15 : 15     numerical simulations, radiative transfer, and first stars

39th Seminar Uncovering the formation of extremely distant galaxies with ALMA

Takuya Hashimoto (Osaka Sangyo University / NAOJ)
October 2018   13 : 30     reionization, ALMA, first galaxies, and first stars

38th Seminar The most rapidly growing black holes: Narrow Line Seyfert 1s across cosmic time

Chris Done (University of Durham)
September 2018   13 : 30     seyfert galaxies, NLS1, AGN, and black holes

37th Seminar Fragmentation in self-gravitating accretion disks; Influence of binary systems

Jannes Klee (University of Kiehl)
August 2018   13 : 30     accretion discs, computational fluid dynamics, and numerical simulations

36th Seminar A New Stellar Population in the Bulge, and a new survey

R. Michael Rich (University of California, Los Angeles (UCLA))
March 2016   10 : 30     galaxy formation and observations

35th Seminar What young stars' infrared variability reveals about protoplanetary disks

Neal Turner (Jet Propulsion Laboratory, Caltech)
October 2015   15 : 30     protoplanetary discs and MHD

34th Seminar Density scratches and formation processes of primordial dark matter haloes via dry mergers

Go Ogiya (LMU/MPI)
October 2015   13 : 30     DM Halo, N-body simulation, and structure formation

33rd Seminar The composition of interstellar molecular gas in galaxies

Nanase Harada (Academia Sinica Institute of Astronomy and Astrophysics (ASIAA))
September 2015   13 : 00     ULIRG, IR, radiative transfer, and protostellar disc

32nd Seminar Radiation transport calculation of the thermal radiation from gamma-ray burst jets

Sanshiro Shibata (Konan University)
March 2015   13 : 30     GRB

31st Seminar (Part 1) Dancing in the dark: galactic properties trace spin swings along the cosmic web

Yohan Dubois (IAP)
October 2014   13 : 30     SMBH and galaxy formation

31st Seminar (Part 2) Exploring the Role of AGN Feedback in Galaxy Formation

Rebekka Bieri (IAP)
October 2014   14 : 30     AGN feedback and galaxy evolution

30th Seminar The Epoch of Reionization: observations and simulations

Benoît Semelin (LERMA, Observatoire de Paris)
September 2014   13 : 30     reionization

29th Seminar A Dynamically Collapsing Cloud Core and a Precursor of a Core in a Filament Supported by Turbulent and Magnetic Pressures

Rei Furuya (Tokushima University)
July 2014   13 : 30     GMC, turbulence, MHD, star formation, molecular cores, and observations

28th Seminar Watching a Little Gas Cloud on its Way into the Galactic Supermassive Black Hole

Andreas Burkert (Ludwig Maximilians Universität München)
February 2014   17 : 00     hydrodynamics, G2, clouds, Galactic center, SMBH, AGN, and accretion discs

27th Seminar (Part 1) Puzzling Features of Quasar Accretion

Charles Steinhardt (Kavli IPMU)
August 2013   15 : 00     quasars, SMBH, and AGN

27th Seminar (Part 3) The Evolution of Star-Forming Galaxies Over Cosmic Time

Josh Speagle (Harvard University, Kavli IPMU)
August 2013   16 : 20     quasars, SMBH, and AGN

27th Seminar (Part 2) How Does Galaxy Environment Influence AGN Activity?

Emil Khabiboulline (Caltech, Kavli IPMU)
August 2013   15 : 40     quasars, SMBH, and AGN

26th Seminar Relativistic Jets and Black Hole Accretion Disks

Geoffrey Bicknell (The Australian National University)
July 2013   14 : 00     AGN, AGN feedback, AGN jets, SMBH, M-sigma relation, MHD, accretion discs, radio galaxies, and Hydra A

25th Seminar 1. The effects of Chern-Simons Gravity and Electromagnetic fields in Blach Hole space-time 2. Space-time rotation induced Landau quantization

Takahashi Rohta (Tomakomai National College of Technology)
March 2012   13 : 30     black holes, general relativity, and radiative transfer

24th Seminar Are Lyman alpha emitters the building blocks of the Milky Way?

Hidenobu Yajima (Pennsylvania State University)
March 2012   13 : 30     LAE, cosmology, radiative transfer, and Milky Way

23rd Seminar The AGN/Starburst connection at z~2 from an IR/submillimeter point of view

Laurie Riguccini (Ehime University)
February 2012   13 : 30     AGN, starbursts, high-z galaxies, galaxy formation, IR, and submm

22nd Seminar The effect of photo-dissociation in the mass accretion phase of PopIII.1 stars

Hajime Susa (Konan University)
December 2011   13 : 30     PopIII stars, accretion discs, radiative feedback, and star formation

21st Seminar The formation of the first stars and galaxies

Thomas Greif (Max Planck Institut für Astrophysik)
September 2011   15 : 00     first stars and first galaxies

20th Seminar (Part 2) Modeling the Electromagnetic Signature of Merging Supermassive Black Holes

Takamitsu Tanaka (Max Planck Institut für Astrophysik)
August 2011   15 : 00     SMBH, SMBH mergers, and accretion discs

20th Seminar (Part 1) A Road to Supermassive Black Hole Merger

Kimitake Hayasaki (Kyoto University)
August 2011   15 : 00     SMBH, SMBH mergers, accretion discs, SPH, and X-rays

19th Seminar Relativistic Jet Feedback in Evolving Galaxies

Alexander Wagner (The Australian National University)
October 2010   15 : 00     AGN jets, AGN feedback, galaxy formation, m-sigma relation, and hydrodynamics

18th Seminar Massive stars in galaxies: their Feedback over their Lives

Gerhardt Hensler (University of Vienna)
September 2010   15 : 00     massive stars and supernovae

17th Seminar The Chemo-dynamical Treatment of Galaxy Evolution

Gerhardt Hensler (University of Vienna)
September 2010   15 : 00     chemodynamics, massive stars, and supernovae

16th Seminar Physics and Fluid-Dynamical Simulations Using GPUs

Muranushi Takayuki (University of Kyoto)
July 2010   15 : 00     GPU and hydrodynamics

15th Seminar Numerical Simulations of High-energy Phenomena in the Universe

Shigehiro Nagataki (Yukawa Institute for Theoretical Physics, Kyoto University)
June 2010   15 : 00     high-energy astrophysics

14th Seminar Performance of Godunov SPH Schemes

Tsukamoto Yusuke (University of Tokyo)
June 2010   15 : 00     SPH, Godunov scheme, and Riemann solvers

13th Seminar Late-type stars in the Andromeda galaxy

Andreas Koch (Leicester University, UK)
June 2010   15 : 00     Andromeda and stellar populations

12th Seminar Black Hole Flywheel Engine Theory and Applications to statistical AGN characteristics

Nitta Shinya (Tsukuba University of Technology)
February 2010   15 : 00     AGN and SMBH

11th Seminar Magnetic field amplification and turbulence in supernova remnants

Tsuyoshi Inoue (National Astronomical Observatory Japan)
February 2010   15 : 00     supernova remnants, MHD, and clouds

10th Seminar The other dynamical friction: Supression of dynamical friction by the core structure of a halo

Shigeki Inoue (Tohoku University)
November 2009   13 : 30     N-body simulations, dark matter, and dynamical friction

9th Seminar Galaxy evolution and cosmic reionization probed through Lyman alpha galaxies

Kazuaki Oota (Riken)
October 2009   13 : 30     LAE and observations

8th Seminar Fast Reionization Simulations for LOFAR

Rajat Mani Thomas (IPMU)
September 2009   14 : 00     reionization, LOFAR, and radiative transfer

7th Seminar Escape fraction of ionizing photons in high-z galaxies: implications on DLAs and LAEs

Kentaro Nagamine (Unversity of Nevada)
August 2009   13 : 30     LAE, DLA, reionization, and hydrodynamics

6th Seminar Evolution of SMBH binaries through interaction with stellar systems

Masaki Iwasawa (NAOJ, Theory Group)
June 2009   13 : 30     SMBH binaries

5th Seminar Testing the black hole paradigm with future observations of SgrA*

Cosimo Bambi (IPMU)
June 2009   13 : 30     SgrA*, black holes, and observations

4th Seminar A New Perspective on the Complex Halo of M31

R. Michael Rich (University of California)
June 2009   14 : 00     Andromeda and galactic halos

3rd Seminar One-dimensional steady-state solution of the black hole accretion disc taking into account the magnetic field

Hiroshi Oda (University of Chiba)
May 2009   13 : 30     accretion discs, SMBH, and MHD

2nd Seminar Numerical simulations with GPU

Naohito Nakasato (University of Aizu)
April 2009   15 : 00     GPU

1st Seminar A submm exploration of the protocluster SSA22

Yoichi Tamura (NAOJ Nobeyama)
April 2009   15 : 00     submm, protoclusters, and observations
  1. Computing the Universe: from Intergalactic to Interstellar Medium, Renyue Cen (Princeton University)   June 2019  
  2. Probing dust aggregate structure in protoplanetary disks by millimeter-wave polarization, Ryo Tazaki (University of Tohoku)   May 2019  
  3. Radiation hydrodynamical simulations of first-star binaries including radiative feedback, Kazuyuki Sugimura (University of Tohoku)   February 2019  
  4. Uncovering the formation of extremely distant galaxies with ALMA, Takuya Hashimoto (Osaka Sangyo University / NAOJ)   October 2018  
  5. The most rapidly growing black holes: Narrow Line Seyfert 1s across cosmic time, Chris Done (University of Durham)   September 2018  
  6. Fragmentation in self-gravitating accretion disks; Influence of binary systems, Jannes Klee (University of Kiehl)   August 2018  
  7. A New Stellar Population in the Bulge, and a new survey, R. Michael Rich (University of California, Los Angeles (UCLA))   March 2016  
  8. What young stars' infrared variability reveals about protoplanetary disks, Neal Turner (Jet Propulsion Laboratory, Caltech)   October 2015  
  9. Density scratches and formation processes of primordial dark matter haloes via dry mergers, Go Ogiya (LMU/MPI)   October 2015  
  10. The composition of interstellar molecular gas in galaxies, Nanase Harada (Academia Sinica Institute of Astronomy and Astrophysics (ASIAA))   September 2015  
  11. Radiation transport calculation of the thermal radiation from gamma-ray burst jets, Sanshiro Shibata (Konan University)   March 2015  
  12. The Epoch of Reionization: observations and simulations, Benoît Semelin (LERMA, Observatoire de Paris)   September 2014  
  13. A Dynamically Collapsing Cloud Core and a Precursor of a Core in a Filament Supported by Turbulent and Magnetic Pressures, Rei Furuya (Tokushima University)   July 2014  
  14. Watching a Little Gas Cloud on its Way into the Galactic Supermassive Black Hole, Andreas Burkert (Ludwig Maximilians Universität München)   February 2014  
  15. How Does Galaxy Environment Influence AGN Activity?, Emil Khabiboulline (Caltech, Kavli IPMU)   August 2013  
  16. Relativistic Jets and Black Hole Accretion Disks, Geoffrey Bicknell (The Australian National University)   July 2013  
  17. 1. The effects of Chern-Simons Gravity and Electromagnetic fields in Blach Hole space-time 2. Space-time rotation induced Landau quantization, Takahashi Rohta (Tomakomai National College of Technology)   March 2012  
  18. Are Lyman alpha emitters the building blocks of the Milky Way?, Hidenobu Yajima (Pennsylvania State University)   March 2012  
  19. The AGN/Starburst connection at z~2 from an IR/submillimeter point of view, Laurie Riguccini (Ehime University)   February 2012  
  20. The effect of photo-dissociation in the mass accretion phase of PopIII.1 stars, Hajime Susa (Konan University)   December 2011  
  21. The formation of the first stars and galaxies, Thomas Greif (Max Planck Institut für Astrophysik)   September 2011  
  22. Modeling the Electromagnetic Signature of Merging Supermassive Black Holes, Takamitsu Tanaka (Max Planck Institut für Astrophysik)   August 2011  
  23. Massive stars in galaxies: their Feedback over their Lives, Gerhardt Hensler (University of Vienna)   September 2010  
  24. The Chemo-dynamical Treatment of Galaxy Evolution, Gerhardt Hensler (University of Vienna)   September 2010  
  25. Physics and Fluid-Dynamical Simulations Using GPUs, Muranushi Takayuki (University of Kyoto)   July 2010  
  26. Numerical Simulations of High-energy Phenomena in the Universe, Shigehiro Nagataki (Yukawa Institute for Theoretical Physics, Kyoto University)   June 2010  
  27. Performance of Godunov SPH Schemes, Tsukamoto Yusuke (University of Tokyo)   June 2010  
  28. Late-type stars in the Andromeda galaxy, Andreas Koch (Leicester University, UK)   June 2010  
  29. Black Hole Flywheel Engine Theory and Applications to statistical AGN characteristics, Nitta Shinya (Tsukuba University of Technology)   February 2010  
  30. Magnetic field amplification and turbulence in supernova remnants, Tsuyoshi Inoue (National Astronomical Observatory Japan)   February 2010  
  31. The other dynamical friction: Supression of dynamical friction by the core structure of a halo, Shigeki Inoue (Tohoku University)   November 2009  
  32. Galaxy evolution and cosmic reionization probed through Lyman alpha galaxies, Kazuaki Oota (Riken)   October 2009  
  33. Fast Reionization Simulations for LOFAR, Rajat Mani Thomas (IPMU)   September 2009  
  34. Escape fraction of ionizing photons in high-z galaxies: implications on DLAs and LAEs, Kentaro Nagamine (Unversity of Nevada)   August 2009  
  35. Evolution of SMBH binaries through interaction with stellar systems, Masaki Iwasawa (NAOJ, Theory Group)   June 2009  
  36. Testing the black hole paradigm with future observations of SgrA*, Cosimo Bambi (IPMU)   June 2009  
  37. A New Perspective on the Complex Halo of M31, R. Michael Rich (University of California)   June 2009  
  38. One-dimensional steady-state solution of the black hole accretion disc taking into account the magnetic field, Hiroshi Oda (University of Chiba)   May 2009  
  39. Numerical simulations with GPU, Naohito Nakasato (University of Aizu)   April 2009  
  40. A submm exploration of the protocluster SSA22, Yoichi Tamura (NAOJ Nobeyama)   April 2009