Nianyi Chen Receives McWilliams Fellowship

Nianyi Chen investigates a colossal topic: black holes.

"My research is about simulating the evolution of the universe, the formation of galaxies and different astrophysical processes," said Chen, a graduate student in Carnegie Mellon University's Department of Physics. "The part I focus on is the supermassive black holes that are mostly located at the center of each galaxy."

Cosmologists believe that small black holes tend to form at the same time as galaxies, when matter and gas cluster together in a high enough density or when stars die and collapse in upon themselves. As these small black holes gradually fall into the center of a galaxy, they absorb gas and matter, growing larger and potentially becoming supermassive.

Previously, researchers have found evidence of black holes merging through gravitational waves. This data mainly comes from smaller black holes, so specific surveys have been planned to look for supermassive black hole mergers.

Chen works with the Pittsburgh Supercomputing Center (PSC) to run large-scale simulations to understand how supermassive black holes merge and what they tell researchers about their host galaxies. Chen is also making predictions on what signals researchers should expect to find when surveying a galaxy for colliding supermassive black holes.

Chen is advised by Tiziana Di Matteo, professor of physics and director of the McWilliams Center of Cosmology. Di Matteo said that Chen's work is helping to guide the future of black hole research.

"She opened up new directions for the understanding of the formation of massive black hole binaries and making predictions for the next generation gravitational wave detection from space," Di Matteo said. "Her work is contributing invaluable knowledge to our understanding of black hole dynamics at the center of galaxies in the early universe."

Chen grew interested in black holes as an undergraduate student when cosmologists first discovered the gravitational waves caused by colliding black holes. She said she was excited how the data expanded the field.

"There are a lot of open questions, so I can develop new methodologies to understand the questions and identify what factors help us make better predictions," Chen said. "I feel like I'm doing things that are expanding some frontiers."

Along with running simulations, Chen works with researchers in the PSC and Carnegie Mellon's School of Computer Science to make astrophysics and cosmology data from the Di Matteo group accessible to other researchers and the general public.

For her work in cosmology, Chen received the Astrid and Bruce McWilliams Graduate Fellowship. The fellowship was donated by the late alumnus Bruce McWilliams to support a graduate student in the Mellon College of Science.

"Nianyi is a brilliant young scientist performing breakthrough research and outstanding academic achievements," Di Matteo said. "Her maturity, and tenacity to always take things one step further are truly impressive. She will make an extraordinary McWilliams Fellow."

Chen will finish her Ph.D. this year. She said the McWilliams fellowship will help her conduct more independent research and transition from her Ph.D. work to postdoctoral work.