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The University of Michigan 
News Service 
412 Maynard 
Ann Arbor, MI 48109-1399

Contact: Judy Steeh
Phone: (734) 647-3099
E-mail: jsteeh{at}umich.edu

April 3, 2003

It's a nova ... it's a supernova ... it's a HYPERNOVA

ANN ARBOR, Mich. -- Two billion years ago, in a far-away
galaxy, a giant star exploded, releasing almost
unbelievable amounts of energy as it collapsed to a
black hole. The light from that explosion finally
reached Earth at 6:37 a.m. EST on March 29, igniting a
frenzy of activity among astronomers worldwide. This
phenomenon has been called a hypernova, playing on the
name of the supernova events that mark the violent end
of massive stars.

With two telescopes separated by about 110 degrees
longitude, the Robotic Optical Transient Search
Experiment (ROTSE) will have one of the most continuous
records of this explosion. 

"The optical brightness of this gamma ray burst is
about 100 times more intense than anything we've ever
seen before. It's also much closer to us than all
other observed bursts so we can study it in
considerably more detail," said Carl W. Akerlof, an
astrophysicist in the Physics Department at the
University of Michigan. Akerlof is the leader of ROTSE,
an international collaboration of astrophysicists using
a network of telescopes specially designed to capture
just this sort of event. The collaboration is
headquartered at U-M and funded by NASA and the
National Science Foundation (NSF).

Just recently, the ROTSE group commissioned two optical
telescopes in Australia and Texas and were waiting for
the first opportunities to use the new equipment. The
burst was promptly detected by NASA's Earth orbiting
High-Energy Transient Explorer (HETE-2) but human
intervention was required to find the exact location.
Despite sporadic clouds and rainstorms in Australia,
the ROTSE instrument at Siding Spring Observatory
in northern New South Wales was able to record the
decaying light from the blast. Twelve hours later,
the second ROTSE telescope in Fort Davis, Texas was
picking up the job of monitoring this spectacular
explosion.

"During the first minute after the explosion it emitted
energy at a rate more than a million times the combined
output of all the stars in the Milky Way. If you
concentrated all the energy that the sun will put out
over its entire 9 billion-year life into a tenth of a
second, then you would have some idea of the brightness,"
said Michael Ashley, faculty member in the astrophysics
and optics department at the University of New South
Wales and a member of the ROTSE team.

Akerlof became interested in studying gamma ray bursts
in the early 1990s. While they are the most powerful
explosions in the universe, gamma-ray bursts are
extremely hard to study because they are extremely
distant, occur randomly in time and seldom last more
than a minute. Small, fast, and relatively inexpensive
robotic ground-based telescopes like ROTSE offer the
best chance of catching early optical emissions from
the bursts. ROTSE attracted national notice in 1999
when it captured the rise and fall of GRB990123, one
of the brightest bursts prior to this latest event.

"The ROTSE equipment is quite modest by modern
standards, but its wide field of view and fast
response allow it to make measurements that more
conventional instruments cannot," Akerlof said. "We
have two telescopes online now, and installations
in Namibia and Turkey will follow soon. Our goal is
to have telescopes continuously trained on the night
sky. Our motto is "The Sun never rises on the ROTSE
array." That's why we want them spread as widely as
possible." 

Another role for ROTSE and other small telescopes is
to alert larger facilities about gamma ray bursts and
other transient phenomena. "One of the most exciting
things about an event like this is the way the global
community of scientists pulls together, pooling their
data and their different capabilities," Akerlof said. 

Related links:

* ROTSE
  http://www.rotse.net/
* U-M Physics Department
  http://www.physics.lsa.umich.edu/nea/
* Carl Akerlof
  http://www.physics.lsa.umich.edu/department/directory/bio.asp?ID=5

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