Dec. 5, 2002
Driven to Discovery
Columbian College Doctoral Student Alaa Ibrahim Encounters
Direct Evidence of a New Type of Star
By Matthew
Lindsay
Alaa Ibrahim has always been drawn to science. Just ask his neighbors.
As a boy in Egypt, Ibrahim would conduct scientific experiments to produce
hydrogen and fuel his model space shuttle. Sometimes his backyard shuttle
launches worked, other times they ended in an explosion — explosions
large enough to get complaints from the neighbors.
Ibrahim, as a physics doctoral candidate under the tutelage of Jean
Swank from NASA’s Goddard Space Flight Center in Maryland, and
GW Professor of Physics William Parke, has focused on studying stars
instead of traveling to them, and launched his career in astrophysics.
In researching what we can learn from particles shot out by a type of
star with an intense magnetic field, Ibrahim made an amazing new discovery.
He found the most powerful large-scale magnetic field known to exist,
and proved the existence of a new type of star, called a magnetar.
“If this magnetar took the place of our moon, its magnetic field
would strip the Earth of every piece of metal and rearrange the molecules
in our bodies,” Ibrahim muses. “Luckily, it is 40,000 to 50,000
light years away from Earth.” [A light year is the distance light
travels in a year, approximately six trillion miles.]
About a decade ago, scientists theorized that the universe contained
magnetars, but had never been able to find direct evidence of their
existence. That is until Ibrahim’s thesis research led him to analyze
data on energy being emitted from a star named SGR 1806-20, which was
believed to be a magnetar. This pointed Ibrahim toward the discovery
that SGR 1806-20 has the most powerful large-scale magnetic field detected
in the universe.
A one-second burst of energy from a magnetar is roughly equivalent to
the amount of energy radiated by our sun in one year. Ibrahim, who has
taught introductory courses in astronomy and physics at GW since 1998,
realizes the implications of his discovery, but is not weighed down
by its enormity.
“This discovery is just one step in a long journey toward learning
more about our universe and magnetars in particular,” says Ibrahim.
“We can begin to test predictions of theoreticians and the laws
of physics in such a strong magnetic field. The more you know, the more
you know there is a lot you need to know.”
The Discovery
The study of magnetars and high-energy astrophysics is relatively new.
March 5, 1979, was a banner day in this field, as an immense burst of
gamma rays hit space probes and then the Earth. These gamma rays did
not disrupt life on Earth because of the atmosphere, but did disrupt
radios momentarily and sent gamma ray detectors off the charts, even
after traveling 50,000 light years. It was not until 1992 that scientists
put forth a theory that magnetars existed and that their incredibly
strong magnetic fields cause the stars’ solid crust to crack and
shoot out powerful bursts of gamma rays.
Enamored by sciences, Ibrahim had narrowed his interest to physics by
high school and went on to earn a BS in physics from Cairo University
in 1991. He came to the United States three years later and received
his MS in nuclear physics from the University of Maryland in 1997. But
it was the time he spent at Goddard Space Flight Center during summer
internships that really amazed him and lured him into the astrophysics
field.
In 1998, Ibrahim began conducting research on magnetars at Goddard Space
Flight Center, along with teaching at GW. Ibrahim believes these wonderful
learning environments allowed him to flourish. He earned his MS in astrophysics
from GW in May, but another major achievement was also within reach.
In combing through the data available from NASA’s Rossi X-ray Explorer
satellite, Ibrahim was able to identify information that pointed toward
a proton moving in an immense magnetic field near SGR 1806-20. Having
previously studied magnetars, he realized that this finding would allow
for direct measurement of the magnetar’s magnetic field, confirming
the amazing strength of that magnetic field and the existence of magnetars.
Ibrahim sought the advice of astrophysics experts in the University
community and at NASA to help him with his research and the publication
of his discovery. The international collaboration included Parke; Swank;
Samar Safi-Harb of the University of Manitoba, Canada; Robert Turolla
of the University of Podova, Italy; and Silvia Zane of the Mullard Space
Science Laboratory in the United Kingdom.
“Alaa’s discovery presents us with an opportunity,” says
Parke. “Testing theories in extreme limits, like the extreme magnetic
field found around magnetars, is the best means of discovering new properties
of our universe and enables us to create new theories.”
The initial results of the team’s discovery were published in a
June 26 article in the Astrophysical Journal Letters, and a more
comprehensive report will appear in the same journal Dec. 10. Ibrahim
speaks about the hard work he and his co-authors had put into this research,
but nonchalantly admits, “The data I analyzed [from SGR 1806-20]
for my thesis was public for years and nobody looked at it.”
“There is a heck of a lot of data available, you just need an idea
of how to analyze it and what to look for, and you may come across new
findings,” Parke confirms.
Certainly, Ibrahim’s background in both nuclear physics and astrophysics
aided him in his discovery, although he is quick to praise GW’s
physics department and the Goddard Space Flight Center. “Without
the availability of the facilities and the people at both GW and Goddard,
we never would have gotten this far,” Ibrahim explains. “The
integration of capabilities and knowledge that led to this discovery
is a formula for success that I hope other students and young scientists
can replicate.”
The Magnetar
A magnetar is a type of neutron star, formed after a supernova, the
death of an ordinary star. An ordinary star produces heat to balance
the force of gravity, but when the star’s fuel is spent and there
is no heat produced, this delicate balance is altered. The interior
collapses into a hard core and then outer layers of the star fall in
and bounce out from the core, sometimes causing a supernova.
“In stars with a range of masses larger than our Sun, this collapse
can form a neutron star, a sphere of nuclear matter approximately the
size of Washington, DC, but still about 1.5 times the mass of the Sun,”
explains Parke.
Neutron stars are extremely hot and rotate quite fast when they first
form. If the conditions are right, the star’s overall magnetic
field can be built up at the birth of the neutron star and a magnetar
can be formed.
The Future
Today, SGR 1806-20 is the only confirmed magnetar, although there are
several other candidates in our galaxy that will need further study.
Both Ibrahim and Parke acknowledge there are almost certainly other
candidates in both our own and distant galaxies that have yet to be
discovered and will not know about until our own technology evolves.
Ibrahim will continue to study SGR 1806-20 and be at the forefront of
research on magnetars. He hopes to earn his doctorate this winter, and,
as someone who enjoys academic life, Ibrahim sees both research and
teaching in his future.
“One of the greatest endeavors of our kind is to help understand
the universe we live in,” Ibrahim says. “I want to help people
understand our universe, but also affect people’s lives on an individual
level.”
Parke applauds Ibrahim’s interest in future research and his success
as a teacher. “It is an amazing combination, to be able to explore
fresh new ideas on the frontier of science and stimulate students to
make new discoveries of their own,” explains Parke.
They both hope to break down barriers they see between young people
and the sciences. Instead of nuclear physicists or astrophysicists,
Ibrahim and Parke would like students to consider them researchers and
teachers of the way things work.
And whether launching test flights of models in a suburban backyard
or discovering new types of stars, one thing is for certain — we
are all intrigued by the way things work.
Send feedback to: bygeorge@gwu.edu
