Dr. Peter Gonthier of the Hope College physics faculty is part of an international team whose on-going research into the nature of the rotating stars known as pulsars has received a new round of support from NASA.
The principal investigator for the grant is Dr. Alice K. Harding of the NASA Goddard Space Flight Center in Greenbelt, Md. The project, “Pulsar Magnetosphere Models and High Energy Emission,” has received $359,284 for the next three years from NASA’s Astrophysics Theory Program, of which $72,000 will support research at Hope that is focused on developing computer models that simulate the stars.
Gonthier is one of six co-investigators on the project, with the team also including researchers from Rice University, the University of Maryland, the Laboratory for High Energy Astrophysics and the University of California as well as the NASA Goddard Space Flight Center. The project also has affiliated collaborators from France, Greece, South Africa and Washington, D.C.
Pulsars are extremely dense neutron stars which have the mass of one and a half of the earth’s sun packed within a ball 16 miles in diameter. They rotate rapidly, completing a revolution in a range between once every 10 seconds and a thousand times a second. Highly magnetized, they shoot out a beam of radiation that, given the spinning, makes the star seem to pulse as the beam passes into view.
Pulsars were discovered in the 1960s, when scientists observed radio waves coming from them. The range of electromagnetic radiation, however, is much broader, covering also microwaves, infrared, visible light, ultraviolet light, X rays and, at the highest end, gamma rays.
As part of the continuing effort of scientists to understand how pulsars function, the computer models being developed at Hope can help show whether or not researchers are on the right path as they interpret what they observe about the stars.
“We want to come to the point where we can adequately describe the observations,” Gonthier said.
“We want to be able to simulate pulsars and compare the characteristics of the simulation with those being observed,” he said. “If we get agreement, it suggests that our models are pretty close, and gives credence to our understanding of what pulsars are doing.”
A nuclear physicist by training, Gonthier has been conducting research on pulsars since 1991. He has served as a lead- or co-investigator on grants from NASA before, and among other related work is one of three leads, along with Harding from Goddard and Dr. Matthew Barring of Rice, in another project currently supported by a grant from the National Science Foundation’s “Research in Undergraduate Institutions” program. The NSF-funded project also involves development of computer modeling as researchers seek to understand the behavior of particles called photons and electrons in magnetars, a variety of pulsar with an intensely high magnetic field.
“We want to provide simple analytic expressions that are useful to a more general astrophysics community,” Gonthier said.
As a matter of course, Hope students work with Gonthier as collaborative researchers, including spending multiple weeks at the NASA Goddard Space Flight Center each summer in addition to other opportunities such as participating in professional conferences. Two, seniors Caleb Billman of New Ringgold, Pa., and Matthew Eiles of Beaverton, Ore., will be accompanying Gonthier to the 13th meeting of the High Energy Astrophysics Division of the American Astronomical Society running April 7-11 in Monterey, Calif.