Elena D’Onghia Models Dynamics of Milky Way

Jul 29, 2013

“A successful life is a teenage dream that comes true when you grow up.”                                                                 --Alfred de Vigny

While watching a TV documentary on comets, Assistant Professor Elena D’Onghia decided to become an astronomer when she was 13 years old. “It took years for my dream to come true,” she says.

Six years earlier, her father had brought home a used encyclopedia, and the chapter on astronomy sparked Elena’s interest. She went on to study the humanities, including Latin, classical literature and philosophy, before switching to physics. “I disproved the widely held belief that someone with a humanistic background does not become a scientist,” she says. Her gymnastic training, which taught her discipline and the need to work hard and never give up, has also served her well in her scientific pursuits.  

Born in the town of Vercelli in the Piedmont region of Italy, Elena studied physics and received her PhD at the University of Milan. She was a postdoc at the Munich Observatory in Germany, a Marie Curie Fellow at the Institute for Theoretical Physics in Switzerland, and
a Keck Fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts before coming to the UW last fall.

Recently awarded a 2013 Alfred P. Sloan Foundation Research Fellowship, Elena will explore how the Milky Way disk formed and evolved. The old stars in our Galaxy date from its earliest history, and their spatial distributions reflect the physical processes that governed the formation of our Milky Way. Ongoing experiments such as the UW-led GLIMPSE survey are mapping the spatial and velocity distributions of the Galaxy's old stars over a larger volume than has previously been possible.

From these data, scientists are able to assemble a picture of the environment in which the stars in the old, thick disk and spheroid components of the Galaxy formed and how they were incorporated into the Galaxy. All of these phenomena cannot be created in a physical science lab. Instead, astrophysicists have to create virtual laboratories on computers in order to simulate the astronomical phenomena in large-scale computational experiments.

The art of modeling the dynamics of the Milky Way through supercomputer simulations of unprecedented resolution is the focus of Elena's research. “This is just a taste of the events to come in the new era of information-rich astronomy, where the entire Galactic disk is imaged to an unprecedented depth,” she says. “It is the interplay between stars orbiting in the disk and the underlying dark matter halo that allows us to use observations to draw conclusions about the properties and dynamics of the Galactic disk through comparisons with simulations.”

Elena’s first results on disk dynamics, published in the Astrophysical Journal (April 1, 2013), argue that the spiral structure generated in the Milky Way’s stellar disk is surprisingly long-lived. “This has important consequences for many aspects of disk evolution, including the currently popular claim that stars such as our Sun can migrate in radius from their birthplaces due to the action of time-variable spiral arms,” she says. “These findings are novel and need new simulation techniques to be developed. This is an area where there is plenty of room for basic breakthroughs.”

Our Galaxy is now being explored in a panchromatic way, leading toward a more complete understanding of its constituents. “My research will include new calculations of the formation of spiral arms by giant molecular clouds and by the impact into the disk of satellite galaxies, all in anticipation of an exciting decade of observations,” she says.

A number of personnel and resources will be invested in these high-resolution numerical simulations and the interfacing of these results to key experiments, especially Sloan Digital Sky Survey IV, an ambitious mission that will create a map of our Galactic disk and nearby galaxies.

“To astronomers, the calm beauty of the night sky in the southern hemisphere is the world’s greatest wonder. The disk of our Galaxy is clearly visible, but understanding it requires both imagination and physical intuition,” says Elena. “I will help to extend our view of the Milky Way as a site of interesting events and begin to look ahead to a truly fascinating period in the history of astronomy.”

UW-Madison Astronomy Home