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Data collection for Galaxy Zoo Mergers is closed.

Data Collection Closed

Thank you again to all of our volunteers. Galaxy Zoo Mergers is now in an archive status. To see the final data release visit the data page here.

The Science

One important area of research in astronomy studies the role of interacting galaxies. Interacting galaxies are galaxies that exhibit a gravitational influence on one another. This influence is exhibited over the cours e of millions or even billions of years as two or more galaxies pass nearby one another. The near passage of two massive structures can cause the galaxies to be distorted and possibly merge.

For example, at least some elliptical galaxies form by collisionsbetween multiple smaller galaxies, which then combine to form one large galaxy, but the process by which spirals form is less well understood. Spiral galaxies might form through a similar process of mergers, or they might form from a single cloud of rotating gas. Studying the specific parameters of a pair or system of interacting galaxies can also help astronomers to estimate the amount of dark matter present. This in turn can help fine-tune other theories about the creation and evolution of the universe.

What we want to know

The set of parameters used to describe a galaxy includes many different quantities. There are angles to represent how each galaxy is oriented with respect to the plane of the sky. There is a mass for each galaxy. The separation in the x, y, and z directions must be specified, along with the equivalent velocities. Even a very simple model to describe two interacting galaxies can require more than a dozen parameters. Consider what it would take to try every combination of parameters. For example, each parameter could be sampled on a very coar se interval so that only 10 individual values were tried. That's the equivalent of sampling an angle that ranges between 0 and 360 degrees at about every 40 degrees. Twelve variables sampled 10 times each would require a trillion, 1000 billion, simulation runs to try all possible combinations.

Luckily it is possible to reduce the number of variables that need to be considered. However, an accurate model requires sampling the variables more than 10 times each.

Galaxy Zoo users have identified close to 3000 galaxy mergers in the SDSS images. When one considers the number of simulations to be checked for just a single pair of interacting galaxies, it becomes clear that an efficient means of sampling different possible simulation parameters is necessary. This website is an attempt to provide an efficient means of searching for the best set of simulation parameters to represent a given pair of interacting galaxies.

The Mergers project aims to provide a set of tools that will allow users to randomly sample various sets of simulation parameters in rapid succession by showing 8 simulation outputs at a time. If any of the 8 outputs appear to be even a crude match to the actual merger image, a user can click on it and highlight it for further study.

To learn more, click on How to Take Part.

What we have learned so far

We present an updated Results page summarizing the wonderful contributions of our volunteers.

Our early results are still available Gallery of some of the initial results. Click here to see some examples of the results contributed by our volunteers.

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