Videos
The geometry of the gas surrounding the Central Molecular Zone: on the origin of localised molecular clouds with extreme velocity dispersions
3D flyby visualisation (click to download mp4) : this 3D visualisation explores the snapshot at t=178Myr of the simulation (the same which is shown in Figs. 2,3,4 in the paper). The colours show the total gas density. It is made using GLnemo2, an interactive visualization 3D program for nbody snapshots developed by Jean-charles LAMBERT and freely downloadable from this link.
Time evolution (click to download mp4) : this video shows the time evolution of the total gas density in the simulation. Shown are both the top-down (x,y) view, which is what we would see by flying over the Galaxy, and the projected (l,b,v) view, which is what we would see from our embedded perspective inside the Galactic disc a the Sun position.
Time evolution zoom (click to download mp4) : same as the previous one, but zooming-in in the innermost 300pc/2degrees.
CO 3D PPV structure of feature V1 (click to download mp4) : this video shows the 3D Position-Position-Velocity structure in CO of the Extended Velocity Feature V1 shown in Fig. 3 in the paper. The CO projections are made in the optically thin approximation.
CO 3D PPV structure of feature V2 (click to download mp4): same as previous video, but for the feature V2 shown in Fig. 5 in the paper.
A theoretical explanation for the Central Molecular Zone asymmetry (click to download pdf)
surface density of whole bar region (inertial frame): variable, low, high
surface density of whole bar region (bar frame): variable, low, high
surface density zoom onto the CMZ (inertial frame): variable, low, high
surface density zoom onto the CMZ (bar frame): variable, low, high
HI longitude-velocity projections (|l|<4 deg): variable, low, high
HI longitude-velocity projections (|l|<30 deg): variable, low, high
HI longitude-velocity projections (|l|<90 deg): variable, low, high
CO longitude-velocity projections (|l|<4 deg): variable, low, high
CO longitude-velocity projections (|l|<30 deg): variable, low, high
CO longitude-velocity projections (|l|<90 deg): variable, low, high
Density cuts along slices parallel to plane z=0: variable, low, high
Click here to download all videos in zip format.
Periodicity makes galactic shocks unstable
A video related to this paper can be found below. This video shows the development of the periodic shock instability in one particular case. The most unstable mode in the video corresponds to k_y=pi in the third row of Fig. 3, more or less at the position of the highest peak in the right panel. The linear analysis predicts the wavelength correctly. The shock oscillates and Re(omega) and Im(omega) from the linear analysis also predict well the timescales. Note that only modes that have k_y = N*pi where N is an integer are possible in this simulation due to the finite size of the box in the y direction. The same simulation with inflow-outflow on the left-right boundaries is stable, i.e. changing the boundary conditions makes the instability disappears and is the periodicity that makes it unstable.Click here to download mp4 video