International study to analyze galaxy formation
Share with others:
Looking back in time sounds like pure science fiction, but that's what happens every time you see a star. The light producing that image has been traveling through time for thousands, millions, even billions of years, depending on how far away the star was at the time.
So you see the star today the way it appeared those many years ago.
And it's that idea taken to the extreme that will allow an international team of astrophysicists to study how galaxies began forming 13 billion years ago.
The team, with Sandra M. Faber of the University of California Santa Cruz as co-leader, will use the Hubble Space Telescope to peer through time and deep space to witness the very beginnings of galaxy formation.
Jeffrey A. Newman, an assistant professor of physics and astronomy at the University of Pittsburgh, is a member of the team which is preparing to have the Hubble take images for 31/2 months -- the longest time period the telescope has been devoted to a single project. The team will have access to the Hubble for 902 full orbits of observation time around Earth in the next two to three years.
One of three large-scale projects chosen for the Hubble Multi-Cycle Treasury Program, the project will generate 250,000 images of distant galaxies in the first comprehensive view of the structure and assembly of galaxies during the first third of cosmic time. More than 100 investigators from universities worldwide are participating in the project.
"Jeff is a remarkable guy," Dr. Faber said, offering her "ringing endorsement" of the Pitt professor as a "brilliant" astronomer. "I would want Jeff to be on any team for any purpose."
Dr. Newman said he's busy determining the size and shapes of spacial fields to be photographed in five spots of sky where the Hubble will be aimed. From those vantage points, the team will capture infrared images of galaxy formation that occurred just 600 million years after the Big Bang.
By studying images of the early universe, astrophysicists finally can determine which theory of galaxy formation holds true. Theories range from primeval galaxies forming independently of each other, to the other theoretical extreme suggesting they were spawned from nurseries of young galaxies.
Hubble images will be released to the world once they are processed so teams of astronomers can compete to analyze data and publish results, with anticipation of a mother lode of information about galactic origins. It's as though astronomers finally will have long-standing questions answered about galaxy formation.
Finding the best locations for images, Dr. Newman said, is akin to deciding which location in the United States offers the best cross-section of Americans.
"You can choose the middle of the country or you can choose Hollywood and you get a different sample," he said, noting the team's interest in sampling a full range of galaxies. "We're looking at a tiny part of the sky, and we want it to be as typical as possible. You might get some extremes, but you also get some in the middle, as well."
The project also will focus on the earliest stages of formation of super-massive black holes and use distant supernovae to help understand how dark energy is involved in accelerating expansion of the universe.
The project will make the best use of the Hubble to provide data for the ages, Dr. Faber said.
The Hubble will use an infrared camera to capture wavelengths of light that expand over time. The size of wavelengths determine the distances images have traveled through time. "We want to look very deep, very far back in time, and see what galaxies and black holes were doing back then," Dr. Faber said in a news release.
Another key question is whether super-massive black holes developed at the very beginning or much later in galaxy evolution and their role in galaxy development.
First observations should be available by year's end.
Dr. Newman said the project should shed light on how our own galaxy, the Milky Way, developed and how the sun formed 4.6 billion years ago. Figuring out how our world was formed to spawn life and human existence represents an ultimate project goal, Dr. Faber said.
The sun, she noted, will last another billion years.
"We have a billion years to play with," she said. "So it would be a tragedy if we chewed ourselves up and disappeared in the next 100 years."
First Published March 16, 2010 12:00 am