Julie Dahlstrom to involve students in
research of mysterious interstellar bands

Julie Dahlstrom, a professor of physics and astronomy at Carthage, is part of a team of researchers that recently received a $1.15 million grant from the National Science Foundation. The grant will fund the multi-institutional study Carriers, Charge State and Diagnostic Use of the Long-Mysterious Diffuse Interstellar Bands.

Prof. Dahlstrom and her students will work with researchers from five other institutions on high-resolution spectroscopy of diffuse interstellar bands, or DIBs. DIBs are unidentified absorption features seen in the spectra of hot, bright stars.

Prof. Dahlstrom, left, stands with students Amanda Faint and Coty Tatge, at the 2010 SURE poster presentation in Hedberg Library Sept. 13. Prof. Paul Martino is pictured at right.

"Generally speaking, we're studying the spectra of stars and other objects in the universe ... using the star as a backlight to study the chemical composition of the gas surrounding it," Prof. Dahlstrom explained. "Light from the star is absorbed in well defined patterns by unidentified substances in the intervening gas."

These DIBs remain a puzzle in observational astrophysics. "There are between 300 and 600 of these features but none correspond with organic molecules previously studied by laboratory spectroscopy," Prof. Dahlstrom said.

A collaborative effort

Prof. Dahlstrom's collaborators on the study are researchers at the University of Chicago, the University of Colorado at Boulder, Johns Hopkins University, Embry-Riddle Aeronautical University, and the Space Telescope Science Institute.

Carthage and Embry-Riddle are the only primarily undergraduate institutions participating in the study. In applying for the grant, "we made a point of saying this was going to present an opportunity for undergraduates to do research," Prof. Dahlstrom said. "The reviewers noted that and commented on it very positively."

"Carthage students will have unprecedented opportunities to work with researchers from a broad spectrum of institutions on a problem of long-standing interest in the astrophysics and astrochemistry communities," said Prof. Kevin Crosby, chair of the Division of Natural Sciences at Carthage. "We can be particularly pleased that this project is a truly interdisciplinary effort drawing on chemists and astrophysicists alike."

Grant continues a decade of work

Scientists from the six participating institutions have been working together on this project for 10 years. "The intention of the grant was to be able to continue this work and give it more attention," said Prof. Dahlstrom, who came to Carthage last fall from the University of Chicago.

The $1.15 million will be divided among the institutions according to their funding needs. Prof. Dahlstrom will be responsible for all data requests and data analysis. "I will also be involved in training any of the graduate students or post-doctoral fellows who will be hired through the University of Chicago," she said.

Part of the work will be purely observational, as researchers catalog all of the information they have on the bands — "where they appear, how broad they are, whether some of their strengths increase or decrease together, to indicate they're from the same compound," Prof. Dahlstrom said. "We have a great archive now of data. We have the largest and overall best quality database for studying this."

Students begin work through SURE program

Prof. Dahlstrom already involved Carthage students in her research this summer. Amanda Faint, '11, and Coty Tatge, '12, conducted research on diffuse interstellar bands as part of Carthage's Summer Undergraduate Research Experience. Jennifer Nicklaus, '11, worked with Prof. Dahlstrom through a Research Experiences for Undergraduates (REU) grant.

"It opened up a new way for me to think about the universe and how it works," said Ms. Faint, a chemistry major, of her summer research project, High Resolution Spectroscopic Studies of the Diffuse Interstellar Bands: The Fullerene Hypothesis. She said the SURE students were excited to receive news of the NSF grant. "There was a lot of whoo-hoo-ing," she laughed. "Dr. Dahlstrom has been there with us and is always available if we have questions, yet we've had a lot of independence."

Ms. Faint plans to continue working with Prof. Dahlstrom this school year, and then study astrochemistry or physical chemistry in graduate school. "It's given me an opportunity to really explore what options there are in my subject area for unique or novel research," she said.