The Johns Hopkins Gazette: January 29, 2001
January 29, 2001
VOL. 30, NO. 19


Astronomer at JHU Gets Pierce Prize

By Michael Purdy
Johns Hopkins Gazette Online Edition

The American Astronomical Society has awarded its top annual prize for young observational astronomers, the Newton Lacy Pierce Prize, to Ken Sembach, a research scientist in the Department of Physics and Astronomy in the Krieger School of Arts and Sciences.

Ken Sembach

The society gives the Pierce award to an astronomer who is 35 or younger and has made unusually significant contributions to astronomical research in the past five years. The awards committee selected Sembach for his research into clouds of gas on the outskirts of the Milky Way galaxy. Sembach has analyzed the composition and motion of these gases to help reveal new insights into the origin and evolutions of galaxies.

"One thing I'd like to make sure to point out is that this work was by no means done in isolation," Sembach says. "I've worked with many collaborators, and this award is reflective not only of my accomplishments but of what my collaborators and I have achieved together."

The award includes a small honorarium and an opportunity for the winner to present details of his research at one of the annual AAS meetings. Sembach has chosen to give his presentation at next winter's AAS meeting.

He says one of the nicest parts of receiving the award has been all the congratulatory e-mail and other messages he's received from colleagues delighted to hear the good news. Sembach is far too modest to brag about the award, but his co-workers aren't hesitant to crow about what a remarkable honor he's won.

"Ken is one of those dynamic individuals who can juggle five balls in the air and still conduct an orchestra," says Bill Blair, an associate research professor who works with Sembach. "The fact that he has garnered such a prestigious science award for his personal research while carrying his functional load is a truly impressive accomplishment."

"The Pierce Prize is the most important prize awarded to a young observational astronomer in this country," says Warren Moos, professor of physics and astronomy. "It is a strong endorsement of the recipient's talents and research, and it marks him as a bright, promising star to watch as his career unfolds."

Sembach is the lead science coordinator and planner for the two largest projects under study by the Far Ultraviolet Spectroscopic Explorer, a NASA satellite observatory operated by Johns Hopkins. Moos is the principal investigator for FUSE.

Sembach was nominated for the Pierce Prize by Blair Savage, a professor of astronomy at the University of Wisconsin at Madison, who was his thesis advisor.

"Ken's work beautifully demonstrates the tremendous power of ultraviolet spectroscopy from orbiting space observatories for obtaining fundamental information about the physical state and distribution of the cold, warm and hot gas in regions of our galaxy up to 120,000 light-years from Earth," Savage says.

Sembach has studied the gases using orbiting spectrometers on both FUSE and the Hubble Space Telescope. Spectroscopy reveals the details of how light from distant stars and galaxies has changed after passing through the gas clouds. Sembach can then use those changes to infer important information about the makeup of the clouds and their motion.

"FUSE is giving us a new look at these clouds because for the first time we can see the real hot gas content of the clouds as well as the cold gas that's associated with the clouds," Sembach says. "From that data, we can get quite a nice handle on the composition and properties of the clouds."

The clouds can shed light both on the history of the Milky Way's evolution and on its future development.

"Ken's studies of these clouds of interstellar gas in the outer parts of the Milky Way are of great importance for understanding the physical processes that control the evolution of the gaseous matter in Milky Way," Savage says.