Research Gallery

The amplitude of the density perturbation grows as it propagates downstream (from left to right) across a C-type shock in a typical environment of star-forming clouds. The growth arises from (...more)

Numerical simulation of low-mass planets migrating in dust-laden protoplanetary disks. The top panels show the perturbed gas and dust densities in the disk with initial metallicity 0.3 and particle Stokes (...more)

Growth rates of the "vertical shear instability" (VSI) in magnetized disks, showing how magnetization stabilizes the VSI. (...more)

Synthetic observations of vortices formed at the outer gap edge of a planet. (...more)

Three-dimensional, dust-plus-gas simulation of a protoplanetary disk with an embedded planet. As the planet carves a gap in the disk, dust grains are elevated to high altitudes. Unlike simple 2D (...more)

Numerical simulation of dust settling in turbulent protoplanetary disks. The color scales show the dust-to-gas ratio on a logarithmic scale. The top panel is taken from a simulation with a (...more)

A schematic diagram of the DPNNet (Disk Planet Neural Network) using a fully connected multi-layer perceptron. The first layer in yellow takes as input six feature variables observed from the (...more)

Structure of linearly unstable modes found in stratified, dusty protoplanetary disks (...more)

Formation of multiple-planet systems in resonant chains around M dwarfs, such as the famous Trappist-1 planetary system. The observed architecture of the orbital resonances depends on the formation time of (...more)

We (Yu-Hsiu Huang, Hiroyuki Hirashita, et al.) modeled dust evolution in Milky Way-like galaxies by post-processing the IllustrisTNG cosmological hydrodynamical simulations in order to predict dust-to-gas ratios and grain size (...more)

Comparison between the numerical estimation of the rim thickness (hatched regions) and observed thicknesses of fine-grained rims (open circles) on the rim thickness and chondrule fraction plane. The dotted line (...more)

Numerical simulations of the time evolution of orbital radii of protoplanets, i.e., their dynamical histories. The top panel is the case for protoplanets around a 1 solar mass star, and (...more)

Based on a one-zone evolution model of grain size distribution in a galaxy, we (Hirashita et al. 2020) calculated the evolution of infrared spectral energy distribution (SED), considering silicate, carbonaceous (...more)

The nebula phase of the magnetar-powered super-luminous supernova from our 3D simulation. At the moment, the supernova ejecta has expanded to a size similar to the solar system. Large scale (...more)

The "streaming instability" (SI) in a physical protoplanetary disk model. (...more)

A thermal bulge of a hot Jupiter is excited by stellar irradiation against a gravitational bulge, thereby maintaining an asynchronous rotation of the planet and preventing the planet from gravitational (...more)

Gas density distribution of the first galaxy after 33 Myr of evolution calculated by Chen & Chen (in preparation). The gas and metals inside supernova remnants mixes with surrounding gas (...more)

We post-processed our cosmological hydrodynamic simulation with a simple dust emission model and calculated the infrared luminosity functions at redshifts z = 1–4 (Aoyama et al. 2019). We compare the (...more)

The evolution of the chondrules fraction in a chondrite parent body (1-χ) as the function of its mass (M_CA) calculated by Matsumoto et al. (submitted). The vertical dotted line shows (...more)

Moment-2 image for the 13C18O J = 3–2 transition of the fiducial model at face on. The location of the circumplanetary disk is labeled. A 4×10-3 stellar mass planet induces (...more)

Exploring protostellar disk formation via misaligned rotation axes and magnetic field, and their observable features. The streamlines on the column density maps show the direction of flows along the picture (...more)

It is well-known that the relativistic outflow, which is driven by the spinning black hole, may NOT originated from the event horizon although the Poynting flux can be produced there (...more)

Quasi-steady funnel jets are obtained in GRMHD simulations up to the scale of ∼ 100 gravitational radius (r_g) for various black hole (BH) spins. The funnel edge is approximately determined (...more)

(A) Side view of a BH magnetosphere. Photons are emitted from infrared to soft gamma-ray energies by the hot gas falling toward the BH in the equatorial, accretion (cyan) region. (...more)

The black solid line is the quadrupole moment of the galaxy power spectrum (the suppression of the power on small scales is due to virial motions of satellite galaxies) and (...more)

The figure shows the constraints on physical boundaries of dark matter halos, known as splashback radii, from the density and velocity fields, respectively shown in the horizontal and vertical axes. (...more)

Distribution of molecular gas surface density (...more)

Cosmological simulation with dust formation and destruction (...more)

How First Supernovae Altered Early Star Formation? (...more)

The evolution paths of aggregates are plotted in the mass-density diagram. (...more)

Footprints of planet formation. Interaction between a low mass protoplanet and its dusty protoplanetary disk. (...more)

Figure shows an example of a nested-grid mesh refinement (NMR) run carried out by the Antares code for a global protoplanetary disk with an embedded circumplanetary disk surrounding a 0.05-Jupiter-mass (...more)

The panel of two figures illustrate the synthetic gas column density and linear polarization component q along the line of sight, inclined 15 degrees from the midplane, for a very (...more)

This figures illustrate density profiles in log scale from simulations of two-temperature model of outflows from a young stellar object. (Left) Mosaic of simulations demonstrating effects of varying temperature and (...more)

Left – Surface density distribution of a forming circumplanetary disk in a protoplanetary disk with the Antares three-dimensional global simulation. A planet of one-Jupiter mass is placed at (x,y) = (...more)

Radial profiles of the 12CO J = 2–1 (left panel) and 13CO J = 2–1 (right panel) emission of the carbon star CIT6 at its systemic velocity observed by the (...more)

Illustration of wind model (left) and attempts to reproduce the velocity pattern of the blue lobe of the I04166 jet (right). The upper part of the left illustration shows two (...more)

Isothermal gas with dust is equivalent to pure gas with cooling. (...more)

Vortex evolution in a self-gravitating disc (top) and a non-self-gravitating disc (bottom). (...more)

Molecular gas is considered to trace star formation activity in galaxies. We calculated the distribution of hydrogen molecules (H2) in a galactic disk based on our hydrodynamical simulation (Chen, Hirashita, (...more)

Figure (a) shows the normalized line profiles of the Ne II 12.81um (blue), Ne III 15.55um (red), and the O I 6300 (black) lines for a X-Wind jet modeled for (...more)

Numerical model for the asymmetric distribution of gas (left panel) and dust (right panel) column density maps of a face-on protoplanetary disk. A massive giant planet (0.5% of the mass (...more)

Stellar density wave of the spiral galaxy M81. Left panel – Theoretical density distribution for a spiral mode. Middle panel – IRAC 3.6 micron map of the non-axisymmetric density distribution. (...more)

A model comparison with an observed pinwheel spiral pattern of AFGL 3068: (a) The original Hubble Space Telescope image (Mauron & Huggins 2006), (b) the observed image overlaid with a (...more)

A schematic sketch of the evolution in star-disk interaction. (...more)

Gas density in the orbital plane of a binary system in the common envelope evolutionary phase. Gas quantities are sampled along the black line (see ApJ 746, 74), revealing the (...more)

The figure compares between the light curves (>100MeV) of the observation and the theory. (...more)

Schematic picture of the truncated outer disk separated from the inner disk by a coronal gap, indicating the energy and mass flow in the configuration. (...more)

Outer-gap death line on the period vs. derivative period plane. Left: entire parameter space. Right: close-up of the millisecond parameter range. (...more)

Phase-averaged spectrum of the pulsed emission from the Crab pulsar predicted by the self-consistent outer gap model. (...more)

Evolution of the photon index Γ (top panel) and the cutoff energy Ec (bottom panel) with the rotational phase is depicted by the (red) thick solid curve. (...more)

Comparisons between the observational intensity maps and the model images calculated from our theory for the galaxy NGC 5248. The left panels, from top to bottom, are B-band, CO (1-0), (...more)

Surface density for single OLR. Spiral waves are excited at 2kpc by a fast bar potential, lying in the horizontal direction. The high density spiral regions would lead to starbust (...more)

The results suggest that neutron stars in systems characterized by low thermal X-ray luminosities (i.e., SAX J1808-3658 and 1H 1905+000) may be of high mass. (...more)

It can be seen that the donor can reveal emission lines in the infrared region. Observations of both the continuum and lines in this wavelength region will provide important insight (...more)

The figures show the number of systems (color coded) for a degree of asymmetry, as measured by K, as a function of the orbital separation, luminosity, mass of the AGB (...more)

The above figures show the density enhancement of the spiral-onion shell shape (a) in the equatorial plane, (b) in a meridional plane, and (c) as a function of the distance (...more)

A schematic view of binary system during the transition from the accretion powered low mass X-ray binary phase to the rotation powered millisecond radio pulsar phase. (...more)

Figure 1 shows DSS image of bright-rimmed cloud SFO21 whose ionizing star is located at 7 pc from the cloud. The arrow and diamond shows the direction of ionizing star (...more)

The figure shows the density structures at 100 (top) and 1000 (bottom) years with four representative numbers n = 1, 2, 4, 6 (from left to right), which indicates the (...more)

Schematic Initial Mass Function (Shu, Li, & Allen, 2004, ApJ, 601, 930) (...more)

SiO(7-6) image generated by non-LTE radiative transfer simulations along with MHD simulation. The low-mass (0.6 solar mass) object at the earliest stage of star formation shows significant irregular morphology compared (...more)