UTSA astronomer receives grant to study the nature of distant galaxies
Chris Packham, associate professor of physics and astronomy at The University of Texas at San Antonio (UTSA), has received a $387,214 grant from the National Science Foundation to support his efforts to better understand the formation and nature of the center of nearby galaxies.
"Most of the galaxies we're looking at are about 10,000 light-years away," Packham said. "They're in our galactic neighborhood, but the neighborhood is very, very big."
The focus of Packham's research is the center of those galaxies, which for some time was the cause for debate among astronomers.
"About a century ago, we found that a very small portion at the center of a galaxy, perhaps 5 to 10 percent, produced more energy than the rest of the entire galaxy put together," he said. "How such a relatively compact object could produce so much energy perplexed us for years."
Now, the source of that energy is generally agreed to be material falling into a supermassive black hole. Stars, and possibly their orbiting planets, revolve around the black hole and are shredded apart as they fall into it. The gas and dust of crumbled stars and planets produce friction as they spiral into the black hole, creating so much light and energy that it's visible from billions of light-years away.
"What we want to understand is why this is happening, how this is happening and what influence it has on the formation of the galaxy that hosts the black hole," Packham said.
With his collaborators, he's begun observing local galaxies with large Earth-based telescopes in Chile, Spain and Hawaii. The project will take a big leap forward in 2018 with the launch of the James Webb Space Telescope (JWST), a space observatory seven times more powerful than the Hubble Space Telescope. The JWST will enable Packham to see farther into the universe without the turbulence of Earth's atmosphere and to detect heat sources, such as galaxies and their black holes, with far greater clarity.
Packham is also part of a larger project with fellow astronomers in the United States, Japan, China, India and Canada to construct a 30 meter-wide telescope in Hawaii, which would allow them to see as far as the JWST but with the advantage of seeing the actual colors of the celestial objects. While the telescope's completion is about 10 years away, Packham is still looking forward to observing black holes and planets orbiting stars in distant galaxies.
"Astronomy's a unique subject," he said. "In biology you can inject a cell with a chemical and in chemistry you can set fire to an element. The only thing you can do in astronomy is look from one direction. You can't see it from the side because it's too far away. You can only look, so every time there's a progression in technology we're able to look better and we get a major revelation in how we understand the universe."
Joanna E. Carver