Here is what the future of computer-simulated galaxy mergers may look like. This image to the right — unusual for its vivid color and detail — shows five stages of a collision between two virtual galaxies, cooked up by computer programs that simulate the processes at work.
View a bigger version of this image.
The image is part of an ongoing project to visualize simulated mergers in a more realistic manner — to produce something more like what you would see through a telescope. T.J. Cox, an astrophysicist at the Harvard Center for Astrophysics, is a member of the team. He kindly provided this work in progress.
Computer models, Cox explains, track the mass and velocity of stars in response to the gravitational disruptions unleashed by close encounters of the galactic kind. But when the Hubble Space Telescope and other observatories view mergers, they see the light emitted by billions of individual stars across a range of wavelengths.
The simplest merger visualizations look like churning swarms of little white “particles” standing in for concentrations of mass (stars) as they interact gravitationally. These visualizations are, as they say, “nothing to look at.”
To get truly realistic mergers, computer models need to include more than just mass particles tugging on each other. The simulations also need to include the effects of gas heating and cooling, star formation, supernova explosions, and absorption of light by interstellar dust.
Cox says that realistic visualizations will make it easier for astronomers to compare theoretical mergers with observations of actual mergers. It would provide modelers and observers a new way to compare notes. And that would make it easier for the theoreticians and observers to interact — much like the colliding galaxies they study. “In a sense,” Cox says, “this enables a feedback loop where the models and observations work in concert to clarify the underlying astrophysics for galaxy formation.”
Check out this realistic-looking animation of a galaxy merger by Patrik Jonsson, another scientist working on the project.
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