The University of Chicago News Office
May 31, 2006 Press Contact: Steve Koppes
(773) 702-8366


A wispy collection of atoms and molecules fuels the vast cosmic maelstroms produced by colliding galaxies and merging supermassive black holes, according to some of the most advanced supercomputer simulations ever conducted on this topic.

“We found that gas is essential in driving the co-evolution of galaxies and supermassive black holes,” said Stelios Kazantzidis, a Fellow in the University of Chicago’s Kavli Institute for Cosmological Physics. He and his collaborators published their in February on astro-ph, an online repository of astronomical research papers. They also are preparing another study.

The collaboration includes Lucio Mayer from the Swiss Federal Institute of Technology, Zurich, Zwitzerland; Monica Colpi, University Milano-Bicocca, Italy; Piero Madau, University of California, Santa Cruz; Thomas Quinn, University of Washington; and James Wadsley, McMaster University, Canada. “This type of work became possible only recently thanks to the increased power of supercomputers,” Mayer said. Improvements in the development of computer code that describes the relevant physics also helped, he said.

“The combination of both code and hardware improvement makes it possible to simulate in a few months time what had required several years of computation time only four to five years ago.” READ MORE

Click the images below to obtain a high-resolution/print photograph for download.

  This image from a supercomputer simulation of colliding galaxies corresponds to approximately five times the diameter of the visible part of the Milky Way galaxy. At this time, the two galaxies interact strongly for the first time.
All photos courtesy of Stelios Kazantzidis (


[Back to top]


  In this image from a supercomputer simulation, gravitational interaction between colliding galaxies generates spectacular tidal tails, plumes and prominent bridges of material connecting the two galaxies.


[Back to top]


  Stelios Kazantzidis


[Back to top]


  In this image from a supercomputer simulation, two galaxies have merged into a single structure and the formation of a nuclear disk of gas. These nuclear disks are believed to provide the fuel that feeds the supermassive black holes in galaxies.


[Back to top]


   The gaseous disks of two galaxies collide in this series of images produced in a supercomputer simulation. Approximately three billion years after the collision begins, the two supermassive black holes at the center of the galaxies merge. Such mergers produce strong gravitational waves, which scientists hope to detect with the proposed Laser Interferometer Space Antenna. An international team of scientists led by Stelios Kazantzidis of the Kavli Institute for Cosmological Physics performed the simulations to elucidate the processes that lead to the merger of supermassive black holes and the production of gravitational waves.


[Back to top]
Last modified at 03:13 PM CST on Thursday, June 01, 2006.

University of Chicago News Office
5801 South Ellis Avenue - Room 200
Chicago, Illinois 60637-1473
(773) 702-8360
Fax: (773) 702-8324
Contact Us