Dr. Matteo Luisi, assistant professor of physics and director of the planetarium and observatory at Westminster College, will present the 2025 Henderson Lecture at 6 p.m., Wednesday, Oct. 15, in the Witherspoon Lakeview Room of the McKelvey Campus Center.

“A New Model of Galactic Ionized Gas” will focus on Luisi’s investigation of the diffuse gas and dust found between stars—or the “interstellar medium”—in the galaxy, culminating in the creation of a new galaxy-wide model of diffuse ionized gas.

“The interstellar medium plays an important role in the evolution of our galaxy,” said Luisi. “Gravity contracts gas clouds in the interstellar medium until they collapse into newborn stars. At the same time, at the end of a star’s life, its outer layers are shed back into the interstellar medium where they will fuel a new generation of stars.”

Luisi’s research specifically focuses on the diffuse ionized gas, a hot ionized phase of the interstellar medium that presumably is ionized by radiation from high-mass stars.

“Because it is difficult to observe directly, we don't know much about the diffuse ionized gas and what role it plays in the evolution of our galaxy,” said Luisi.

Luisi is part of a team of researchers that is creating a new model for the diffuse ionized gas based on previous and ongoing observations with the Green Bank Telescope in West Virginia and on observations with the James Webb Space Telescope (JWST), the most powerful space telescope currently in existence.

Last fall, the team was awarded 5.1 hours of observation time using the JWST—valued at roughly $870,000—to study ionized gas in the galaxy.  Observations obtained from using the JWST will help Luisi and his team gain a greater knowledge of the interstellar medium.  

“These observations will also help us determine the physical properties of the gas such as its density and temperature. These results will allow us to figure out what causes the ionization of the gas—whether it is truly massive stars or if other sources are important as well—and tell us more about the interplay between the diffuse ionized gas and other phases of the interstellar medium, providing insight on how different gas phases interact and how they affect star formation and galactic evolution,” Luisi said.

Luisi, who joined the Westminster College faculty in 2021, earned his undergraduate and master’s degrees in technical physics from Graz University of Technology in Austria and his doctorate in physics from West Virginia University.

The Henderson Lecture was founded by the late Dr. Joseph R. Henderson and his wife, Elizabeth, to encourage and recognize original and continuing research and scholarship among Westminster College faculty, and to afford the opportunity for faculty to share their learning with the academic community. Dr. Henderson was a professor of education emeritus at Westminster, having served as chair of the Department of Education and as director of the Graduate Program.

Each year, Westminster faculty members may nominate themselves or others to receive the lectureship, which includes a stipend to support a specific research project. A faculty committee chooses the winner.

The lecture is free and open to the public. For more information about Luisi’s research, contact him at luisimd@westminster.edu.

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