Understanding gas accretion to the central supermassive black hole of galaxies has developed greatly and the standard disk model which appeared in the 1970s, has been extended by a slim disk model and a quasi-one-dimensional advection dominated accretion flow (ADAF) sometimes know as a radiatively inefficent accretion flow (RIAF) model....

Figure: Side-on view of galaxies colliding from the left and right. White solid square is a region that has already been observed by the Japanese X-ray satellite Suzaku (Fujita et al. 2008 PASJ, 60, S343), while the white dotted line shows the newly predicted region of the shock-front. The panels...