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Past Winner
2003 E.W.R. Steacie Memorial Fellowship

Victoria Kaspi

Astrophysics

McGill University


Victoria Kaspi
Victoria Kaspi

If astrophysicist Dr. Victoria Kaspi were a wrestler she'd have some serious bad-mouth bragging rights. This scientist is using x-ray vision to corner billion-year-old cosmic objects that give new meaning to the terms big and powerful.

"Imagine an object one-and-a-half times the mass of the Sun, crushed into the size of Montreal and rotating as fast as a household blender," says the McGill University physics professor about one type of neutron star called a "millisecond pulsar." And, as if this isn't impressive enough, neutron stars are the densest visible objects in the universe: a single tablespoon of the stuff weighs about one billion tonnes.

"Physics doesn't yet know what is going on with matter at such high densities," says Dr. Kaspi, one of six recipients of a 2003 NSERC E.W.R. Steacie Memorial Fellowship and holder of the Canada Research Chair in Observational Astrophysics at McGill University. "You can't reproduce these conditions in a laboratory. In fact, a neutron star is the only place in the universe where matter can exist at such high densities."

As such, these remnants of collapsed stars (which are the close cousins of black holes) provide a unique window into the physics of matter at these extremes. Dr. Kaspi's research team is using the world's most advanced satellite-based x-ray telescopes, including NASA's $1-billion Chandra X-Ray Observatory, as well as the largest Earth-based radio telescopes to locate and study the behaviour of these cosmic heavy weights.

This past summer, her eight-person research group identified a new type of magnetar, a type of neutron star whose emitted energy comes not from fusion (as with our sun), or its rotational energy (as with pulsars) but from its enormous magnetic field. In the September 12, 2002, issue of Nature, the group reported the first observations of distinctive bursts of x-rays from so-called anomalous x-ray pulsars.

"What we proved is that anomalous x-ray pulsars are also magnetars, and that explains their energy source," says Dr. Kaspi. "But discovering these energy bursts is just opening a whole new field, so we're going to continue to study them. We don't know why they burst, how often they burst, or any number of other questions that we want to attack."

As an NSERC Steacie Fellow, Dr. Kaspi will also be scanning the Milky Way for as yet undiscovered millisecond pulsars. This cosmic search involves collecting terabytes (trillions of bytes) of radio telescope data. To analyze it for the tell-tale millisecond radio wave pulses produced by pulsars, Dr. Kaspi's team turns to The Borg (a name that betrays her love of science fiction). The cluster supercomputer consists of 52 nodes of processors and is one of the world's most powerful computers dedicated to pulsar research.

One goal of this research is to pin down maximum spin speeds of the pulsars. Her team has already found some rotating at around 300 times a second. If she can find one spinning at twice this speed, it would clarify the types and state of matter in these dead stars. It's a search for the extreme that has Dr. Kaspi laugh while asking, "Just how fast can one of these things spin?"