An Iowa State astronomer is working with images recently taken by the Hubble Space Telescope to determine how galaxies collide and stars are formed.

Curt Struck, professor of physics and astronomy, is collaborating with a team of researchers through the Hubble Heritage Project to process images of colliding galaxies to release to the public. Studying these collisions will help scientists understand galactic structure and how stars are formed, Struck said.

The new images are of two colliding galaxies named NGC2207 and IC2163. The image released to the public is actually a combination of three separate images taken over a period of many months, Struck said.

“Collisions almost always result in a merger [of the galaxies],” he said.

Struck said the individual stars in a galaxy rarely collide, however.

“There is so much space between stars in a galaxy that they go through each other,” he said.

It is the collision of interstellar dust clouds that bring about new star formations, he said.

“When they collide, it disturbs the interstellar gas,” he said. Struck said this disruption allows gravity to bring the dust and gas together forming new stars.

He said galaxies normally produce new stars at a rate of only a few per year, but when galaxies collide, that rate can increase.

“In a collisional system, it can be turned on to many times that,” he said. “It is possible that rate would be up to thousands of times the normal rate.”

The Hubble Telescope provides resolution that ground-based telescopes cannot achieve, so in a galaxy collision 114 million light years away, astronomers can see individual star clusters, Struck said.

The gas and dust clouds are also remarkably clear because of back lighting by one galaxy in front of the other, he said.

“There are only a few cases where you can study the features of a galaxy that are back lit in this way. It allows us to see star dust, material that eventually could develop into stars sometime down the road,” he said.

The goal of the Hubble Heritage Project is to bring Hubble images to the public.

“Our goal is to find images that have not been distributed yet,” said Zolt Lavey, a fellow member of the project.

Lavey worked with Struck and the other researchers to present the images to the public.

The group chooses images from the Hubble Space Telescope each month and publishes them on its Web site with nontechnical information describing the picture. They also distribute the information to news organizations.

“It is a way of reaching a larger audience,” Lavey said.