CANADIAN ASSOCIATIONOF PHYSICISTS |
ASSOCIATION CANADIENNE DESPHYSICIENS ET PHYSICIENNES |

**PRESS RELEASE / FOR IMMEDIATE RELEASE**

**2005 CAP Herzberg Medal**

will be awarded to

**DR. ERIC POISSON**

*"It is a most significant honour to be awarded the Herzberg Medal and to be included into this group of celebrated physicists. It is all the more sweet that this is taking place in 2005, the World Year of Physics."*

The Canadian Association of Physicists (CAP) is pleased to announce that the 2005 Herzberg Medal is awarded to Dr. Eric Poisson, University of Guelph for his work in the physics of black holes and gravitational waves. His solutions of Einstein's field equations are used to by groups who build gravitational wave detectors, such as LIGO, to estimate the signatures from cosmic events such as the merging of two black holes.

Eric Poisson's research activities have revolved around the physics of black holes and gravitational waves. As a graduate student at the University of Alberta working with his advisor Werner Israel, he investigated the structure of black hole interiors. They demonstrated the existence of a phenomenon called mass-inflation, in which the internal mass function of the black hole increases without bound, implying that, contrary to expectations, the singularity is not everywhere spacelike but contains a portion that is lightlike. Mass inflation has become standard lore in gravitational physics and -- after nearly 15 years of scrutiny -- the basic picture first put forth by Poisson and Israel has needed no modification. His work on black-hole interiors has been reviewed in popular science books as well as in the scientific press.

Eric’s work on gravitational waves was motivated by the worldwide effort to model the signals that might eventually be detected by the planned Earth-based and space-based laser interferometers such as LIGO and LISA. By modeling the binary system as a point-like object orbiting a much more massive black hole, he was able to solve the perturbative gravitational wave equations without relying on a weak-field and slow-motion approximation, and showed that the standard post-Newtonian treatment of the problem (which relies on such approximations) was not very accurate and needed to be pushed to very high order. His famous 4p correction is now part of the theoretical waveforms that are used by gravitational-wave observatories as matched filters for wave detection. Eric’s current efforts are devoted to the problem of determining the motion of a small mass around a much larger body (taken to be a black hole). This type of binary system is an important source of gravitational waves for a space-based detector, and a detailed understanding of the waves requires a detailed understanding of the motion.

The CAP Herzberg Medal was first introduced in 1970 and is awarded annually. Dr. Poisson will receive the 2005 Prize during the CAP's awards banquet to be held at the University of British Columbia on June 7th, 2005.

The Canadian Association of Physicists, founded in 1945, is a professional association representing over 1600 individual physicists and physics students in Canada, the U.S. and overseas, as well as a number of Corporate and Departmental Members. In addition to its learned activities, the CAP also undertakes a number of activities intended to encourage students to pursue a career in physics.

For more information, please contact:

Canadian Association of Physicists

Tel: (613) 562-5614

Fax: (613) 562-5615

E-mail: cap@physics.uottawa.ca