Amateur Astronomer Locates Powerful Stellar Explosion Before the Pros

Nancy Neal
Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301/286-0039)

Armed with a 12-inch telescope, a computer, and an AAVSO e-mail alert, Berto Monard of South Africa has become the first amateur astronomer to discover an afterglow of a gamma-ray burst (GRB), the most powerful explosion known in the Universe. The discovery highlights the importance of amateur astronomers to a cutting edge field of astronomy.

NASA's High-Energy Transient Explorer (HETE) satellite detected a 40-second-long burst on July 25. However, due to complications associated with observing high energy phenomenon, only a rough location estimate could be determined. This estimate was distributed to NASA's Global Coordinates Network (GCN), a GRB alert network for professional astronomers. The alert was then redistributed to Monard by the American Association of Variable Star Observers (AAVSO).

Monard imaged the area around the estimate and found the lingering afterglow of the GRB. His discovery and subsequent localization has given way to precision follow-up study, an opportunity that very well might have been missed: At the time of the burst, thousands of professional astronomers were attending the International Astronomical Union conference in Sydney, Australia, far away from their observatories.

"I have seen a multitude of stars and galaxies and even supernovae, but this gamma-ray burst afterglow is among the most ancient light that has ever graced my telescope," Monard said. "The explosion that caused this likely occurred billions of years ago, before the Earth was formed."

Gamma-ray bursts, many of which now appear to be massive star explosions billions of light years away, only last for a few milliseconds to upwards of a minute. Prompt identification of an afterglow is crucial for piecing together the explosion that caused the burst. However, the afterglows fade rapidly. Within a few hours they usually fade beyond the limits of even moderate size telescopes.

A quick announcement of Monard's discovery was distributed to the pros by the AAVSO. The Interplanetary Network (IPN), comprising six orbiting gamma-ray detectors, confirmed the location shortly thereafter.

The typical GRB alert pattern follows: HETE detects a burst and, within a few seconds to about a minute, relays a location to the GCN. Instantly, the automated GCN notifies professionals. The AAVSO takes this notice and distributes it to a team of amateur astronomers they have trained for just this mission, known as the AAVSO International High Energy Network.

The International High Energy Network has 185 members in 22 countries. These members get notified of a GRB alert via e-mail, pager, and cell phone. When an alert goes out finder charts and other materials needed to search for the afterglow are automatically generated on the AAVSO web site.

"In the past two years, HETE has opened the door wide for rapid follow-up studies by professional astronomers," said HETE Principal Investigator George Ricker of MIT. "Now, with GRB030725, the worldwide community of dedicated and expert amateur astronomers coordinated through the AAVSO is leaping through that door to join the fun."

Amateur astronomers are needed in this field because their numbers and geographical distribution provide for worldwide coverage of the sky. They can also observe a field quickly since they are not restricted by observing schedules and other overhead. The extra few minutes that saves can be critical in afterglow research.

Monard, a Belgian national living in South Africa, has other discoveries under his belt, including ten supernovae.

The AAVSO, founded in 1911, is a non-profit, scientific organization with members in 46 countries. It coordinates, compiles, digitizes and disseminates observations on stars that change in brightness (variable stars) to researchers and educators worldwide.

The AAVSO International High Energy Network was created in 2000 with cooperation from NASA and support from the Curry Foundation. The network also monitors blazars in support of the upcoming GLAST satellite mission and magnetic variables ("polars") in support of the XMM Newton satellite observatory. The network trains and coordinates the observers and then distributes their results to professionals in the form of raw data and publication of papers.

HETE was built by the Massachusetts Institute of Technology under NASA's Explorer Program. HETE is a collaboration among NASA, MIT, Los Alamos National Laboratory; France's Centre National d'Etudes Spatiales, Centre d'Etude Spatiale des Rayonnements, and Ecole Nationale Superieure de l'Aeronautique et de l'Espace; and Japan's Institute of Physical and Chemical Research (RIKEN). The science team includes members from the University of California (Berkeley and Santa Cruz) and the University of Chicago, as well as from Brazil, India and Italy.

For more information on NASA please consult the following website: http://www.nasa.gov

Interested amateurs are encouraged to sign up for the network through the AAVSO web site at:
http://www.aavso.org.