Duncan Brown, assistant professor of physics in Syracuse University's
College of Arts and
Sciences, was recently awarded the National Science Foundation's Faculty Early Career
Development (CAREER) Award. The award includes a five-year, $550,000 grant that will
enable Brown to expand his study of black holes and gravitational waves.
The CAREER Award, the NSF's most prestigious and competitive award for young faculty
members, recognizes outstanding scientists and engineers who, early in their careers, show
exceptional potential for leadership.
Black holes are massive gravitational fields in the universe that result from the collapse of giant
stars. Scientists believe that gravitational waves are emitted when black holes crash into each
other or into neutron stars. Brown is among a large group of scientists, from the United States
and abroad, who are affiliated with the NSF-funded Laser Interferometer Gravitational-Wave
Observatory (LIGO) in Hanford, Wash., and Livingston, La., which was built to detect and
study gravitational waves. Detectors have also been built in Europe and Japan.
"Looking for gravitational waves is like listening to the universe," Brown says. "Different kinds
of events produce different wave patterns. We can learn a lot about the nature of black holes by
studying the wave patterns that result from collisions."
While the work at LIGO has expanded scientific understanding of the universe, scientists have
not yet "heard" a gravitational wave signal. In addition to any signals, the LIGO detectors
contain noise from many different sources, Brown says. Trying to hear a gravitational wave with
LIGO is like trying to hear a whisper in a room full of chattering people.
Brown will use some of the funding from his CAREER Award to develop new listening
technologies-computer algorithms and software tools-that will be used with the enhanced
LIGO detectors that are scheduled to come online in July. He will also explore new tools that
could be used with the next generation of LIGO detectors, which will be completed in 2014.
"Current technologies can only detect signals from nearby events," Brown says. "By improving
our search methods, we will be able to see further out in the universe and hopefully expand our
ability to detect gravitational waves and use them to study the universe."
Brown's CAREER Award will also enable him to continue his work on a relatively new project
called NINJA (Numerical INJection Analysis). NINJA is a unique collaboration between
gravitational wave physicists and numerical relativists-physicists who develop computer
models of what the waves from colliding black holes should look like.
Most stars in the universe exist in pairs or "binary systems" that rotate around each other. When
the stars exhaust their fuel supply, they collapse and can form black holes or neutron stars. They
continue as a binary pair until gravitational forces sap their energy, causing them to collide.
Albert Einstein first predicted the behavior of these systems in his Theory of Relativity.
Simulating the collision of two black holes is extremely complicated, and the mathematical
breakthrough that allowed scientists to model these spiraling holes occurred just four years ago.
The NINJA project is a series of experiments that is putting these models to the test. Scientists
participating in NINJA simulate black hole collisions and bury signals from their models in the
LIGO data. Other research teams then sift through the aggregate data in an attempt to identify
the theoretical wave patterns and use them to determine the masses, spins and orbital shapes of
the simulated black holes. The experiments have so far been very successful. Results from
NINJA were presented in August 2008 during a joint conference at SU for numerical-relativity
and gravitational wave researchers.
"The future of gravitational wave astronomy is very bright," Brown says. "With strong support
from the NSF and the combined efforts of theorists and experimentalists in the gravitational
wave research community, we can improve our chances of detecting these signals, and enhance
our understanding of black holes and how they interact with the universe."
