Ph.D. Candidate, Physics and Astronomy
“The gas in clusters of galaxies constitutes the bulk of the luminous matter in those clusters, even more than the galaxies themselves. Chandra observations of these clusters have revealed sharp edges in the brightness distributions, which were previously thought to be smooth. My goal is to study the possible sources of these edges and to understand the motions of gas that may be causing them.”
—Ryan Johnson
Ph.D. Candidate, Physics and Astronomy
Pre-doctoral Fellowship
Harvard-Smithsonian Center for Astrophysics
Photo by Joseph Mehling
“I explicitly came to Dartmouth with the hope of working with Professor Wegner,” says Ryan. “We started on a project in the spring of my first year and have been working together ever since.”
In the beginning, Johnson met with Wegner several times a week to confer on his progress. Then three years into his doctoral program, Johnson began working fairly independently; now he checks in with Wegner only when one of them has new results to share with the other.
Johnson focuses his work on galaxy clusters, the largest gravitationally bound objects in the universe.
“Because gravity is drawing them all towards one another, occasionally they pass each other close enough that we observe tidal disruptions in their gas,” says Johnson. “I study this gas using X-ray observations from the Chandra space telescope.”
Johnson says his research goal is ultimately to determine the fundamental properties of the gas (density, temperature, and pressure) and to better describe its motion on these extremely large scales.
Outside the lab, Johnson says when he first came to Dartmouth he often went to movies and music concerts in the local area, or hiking in the scenic mountains around Hanover. He and his first-year graduate student classmates hung out together in North Park graduate housing, or hit Five Old for drinks. He also began organizing sporadic happy hours with students from other physical sciences departments.
Recently, he and his wife had a baby daughter, and much of his free time is spent looking after her. Although he says, “This winter, during the daylight hours, chances are good you’ll find me at the Dartmouth Skiway.”
Nighttime will likely find Johnson balancing new fatherhood and pondering distant galaxy clusters and the intricate dance they weave with one another.
