Relativistic Godunov SPH Simulations of High-Velocity Jets from Compact Astrophysical Objects

Kanta Kitajima

Nagoya University

Relativistic jets are widely observed in astronomical objects including active galactic nuclei and gamma-ray bursts. However, the acceleration mechanisms that drive these jets are not yet fully understood. Recent studies have shown that when a jet possesses an initial velocity corresponding to approximately 90% of the speed of light, it...

Low frequency radio observation with MWA and SKA Low exploring the cosmic dawn and epoch of reionization

Shintaro Yoshiura

National Astronomical Observatory of Japan

The Square Kilometre Array (SKA) Low and Mid, the world's largest radio telescopes, are currently under construction in Australia and South Africa. Covering frequency ranges of 50–350 MHz for SKA Low and 350 MHz–15.4 GHz for SKA Mid, the SKA will enable a wide range of scientific studies, leveraging its...

Tracing Early Galaxy Formation with FirstLight Zoom-In Simulations: Statistical Insights and Inner Structures of $z>6$ Galaxies

Yurina Nakazato

University of Tokyo

Recent JWST observations have revealed a wealth of detail about high-redshift galaxies, including strong [OIII] emission and clumpy structures. To interpret these observations, we utilize FirstLight zoom-in simulations with pc-scale resolution. This talk will discuss: (1) the physical properties of [OIII] emitters and the use of line diagnostics, (2) the...

Theoretical models of optically-thick accretion disk corona

Norita Kawanaka

NAOJ/Tokyo Metropolitan University

This talk is about modelling the X-ray emission from black hole accretion discs. We discuss the standard model for these discs, and how this model needs to be modified in order to explain the observational data, in particular from super-Eddington discs and X-ray binaries. The standard model is a simple...

Formation of Young Massive Clusters by Fast HI Gas Collision

Ryunosuke Maeda

Tohoku University

We present simulations of the formation of young massive clusters (YMCs) through high-velocity collisions of HI gas in the Large Magellanic Cloud. The simulation models the magnetized interstellar gas dynamics, including the effects of self-gravity, heating/cooling, and stellar feedback. The results show that fast collisions of HI gas can form...

IMF transition across various environments in the early universe

Ito Mana

Tohoku University

We study the thermal evolution of star-forming clouds in the primordial halos at $z>100$, considering the effect of the cosmic microwave background (CMB). The CMB inhibits the formation of H2 via the photodissociation of H-, resulting in a higher temperature than in the standard evolution of the first stars at...

Investigating Black Hole-Disk-Jet System through Polarization Images

Yuh Tsunetoe

Harvard University

We investigate the innermost structure of black hole-disk-jet systems through polarization images. First, we focus on linear and circular polarization (LP and CP) separation along the jet, based on our general relativistic radiation transfer code. We find that the LP and CP components are separated by the Faraday effects. Next,...

Protoplanetary disk evolution: fragmentation and dust ring formation

Ryoki Matsukoba

Kyoto University

We study the metallicity dependence of the disk fragmentation using 2D hydrodynamics simulations. We perform long-term simulations up to 0.1 Myr with a wide metallicity range of $10^{-5}Z_{\odot} May 2024   13 : 00     protoplanetary discs, hydrodynamics, and dust

State Transitions and Time Variations of Black Hole Accretion Flows

Ryoji Matsumoto

Chiba University

Black hole candidates display transitions between hard and soft X-ray states. During the transition, quasi-periodic oscillations and jet ejections are observed, and the black hole accretion flow shows intense activity. Our group has investigated the process of the formation of the soft X-ray emitting region by the cooling of the...

A fierce new challenge: unveiling the connection between the first galaxies and reionization

Enrico Garaldi

Max-Planck-Institut für Astrophysik

The Epoch of Reionization (EoR) shaped the properties of the baryonic content of the Universe. Using hydrodynamical and radiative-transfer numerical simulations, we investigate in detail the processes taking place in the IGM before, during and after the EoR. Present and future observations by, e.g., PAPER, LOFAR, SKA, and E-ELT, will...

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...

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...

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...

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...

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...

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...

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...

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...

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 talk we present two recent results. 1. In the case in which the two colliding systems...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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....

52^nd Colloquium Relativistic Godunov SPH Simulations of High-Velocity Jets from Compact Astrophysical Objects

Kanta Kitajima (Nagoya University)

51^st Colloquium Low frequency radio observation with MWA and SKA Low exploring the cosmic dawn and epoch of reionization

Shintaro Yoshiura (National Astronomical Observatory of Japan)

50^th Colloquium Tracing Early Galaxy Formation with FirstLight Zoom-In Simulations: Statistical Insights and Inner Structures of $z>6$ Galaxies

Yurina Nakazato (University of Tokyo)

49^th Colloquium Theoretical models of optically-thick accretion disk corona

Norita Kawanaka (NAOJ/Tokyo Metropolitan University)

48^th Colloquium Formation of Young Massive Clusters by Fast HI Gas Collision

Ryunosuke Maeda (Tohoku University)

47^th Colloquium IMF transition across various environments in the early universe

Ito Mana (Tohoku University)

46^th Colloquium Investigating Black Hole-Disk-Jet System through Polarization Images

Yuh Tsunetoe (Harvard University)

45^th Colloquium Protoplanetary disk evolution: fragmentation and dust ring formation

Ryoki Matsukoba (Kyoto University)

44^th Colloquium State Transitions and Time Variations of Black Hole Accretion Flows

Ryoji Matsumoto (Chiba University)

43^rd Colloquium A fierce new challenge: unveiling the connection between the first galaxies and reionization

Enrico Garaldi (Max-Planck-Institut für Astrophysik)

42^nd Colloquium Computing the Universe: from Intergalactic to Interstellar Medium

Renyue Cen (Princeton University)

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

Ryo Tazaki (University of Tohoku)

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

Kazuyuki Sugimura (University of Tohoku)

39^th Colloquium Uncovering the formation of extremely distant galaxies with ALMA

Takuya Hashimoto (Osaka Sangyo University / NAOJ)

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

Chris Done (University of Durham)

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

Jannes Klee (University of Kiehl)

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

R. Michael Rich (University of California, Los Angeles (UCLA))

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

Neal Turner (Jet Propulsion Laboratory, Caltech)

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

Go Ogiya (LMU/MPI)

33^rd Colloquium The composition of interstellar molecular gas in galaxies

Nanase Harada (Academia Sinica Institute of Astronomy and Astrophysics (ASIAA))

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

Sanshiro Shibata (Konan University)

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

Yohan Dubois (IAP)

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

Rebekka Bieri (IAP)

30^th Colloquium The Epoch of Reionization: observations and simulations

Benoît Semelin (LERMA, Observatoire de Paris)

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

Rei Furuya (Tokushima University)

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

Andreas Burkert (Ludwig Maximilians Universität München)

27^th Colloquium (Part 1) Puzzling Features of Quasar Accretion

Charles Steinhardt (Kavli IPMU)

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

Josh Speagle (Harvard University, Kavli IPMU)

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

Emil Khabiboulline (Caltech, Kavli IPMU)

26^th Colloquium Relativistic Jets and Black Hole Accretion Disks

Geoffrey Bicknell (The Australian National University)

25^th Colloquium 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)

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

Hidenobu Yajima (Pennsylvania State University)

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

Laurie Riguccini (Ehime University)

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

Hajime Susa (Konan University)

21^st Colloquium The formation of the first stars and galaxies

Thomas Greif (Max Planck Institut für Astrophysik)

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

Takamitsu Tanaka (Max Planck Institut für Astrophysik)

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

Kimitake Hayasaki (Kyoto University)

19^th Colloquium Relativistic Jet Feedback in Evolving Galaxies

Alexander Wagner (The Australian National University)

18^th Colloquium Massive stars in galaxies: their Feedback over their Lives

Gerhardt Hensler (University of Vienna)

17^th Colloquium The Chemo-dynamical Treatment of Galaxy Evolution

Gerhardt Hensler (University of Vienna)

16^th Colloquium Physics and Fluid-Dynamical Simulations Using GPUs

Muranushi Takayuki (University of Kyoto)

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

Shigehiro Nagataki (Yukawa Institute for Theoretical Physics, Kyoto University)

14^th Colloquium Performance of Godunov SPH Schemes

Tsukamoto Yusuke (University of Tokyo)

13^th Colloquium Late-type stars in the Andromeda galaxy

Andreas Koch (Leicester University, UK)

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

Nitta Shinya (Tsukuba University of Technology)

11^th Colloquium Magnetic field amplification and turbulence in supernova remnants

Tsuyoshi Inoue (National Astronomical Observatory Japan)

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

Shigeki Inoue (Tohoku University)

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

Kazuaki Oota (Riken)

8^th Colloquium Fast Reionization Simulations for LOFAR

Rajat Mani Thomas (IPMU)

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

Kentaro Nagamine (Unversity of Nevada)

6^th Colloquium Evolution of SMBH binaries through interaction with stellar systems

Masaki Iwasawa (NAOJ, Theory Group)

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

Cosimo Bambi (IPMU)

4^th Colloquium A New Perspective on the Complex Halo of M31

R. Michael Rich (University of California)

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

Hiroshi Oda (University of Chiba)

2^nd Colloquium Numerical simulations with GPU

Naohito Nakasato (University of Aizu)

1^st Colloquium A submm exploration of the protocluster SSA22

Yoichi Tamura (NAOJ Nobeyama)