High Energy Astrophysicsfor Everybody
April
12, 2000 -- Astronomers from all over the United States and
from 10 countries will converge in Huntsville, Alabama today
for a series of meetings and lectures. Approximately eighty participants
will learn about the latest findings in the field of high-energy
astrophysics from a dozen research scientists.
Sounds like another dry scientific meeting, right?
Wrong.
"We selected the attendees in part by asking how they would share their knowledge with others," says Janet Mattei, director of the American Association of Variable Star Observers (AAVSO), which is co-sponsoring the meeting along with the Marshall Space Flight Center. "We got some fantastic responses from astronomy club presidents, planetarium workers, and teachers ... just wonderful responses. There's a real need to bring high-energy astronomy to the attention of the public, and we think these are the right people to do it."
"The usual connotation of 'amateur' really doesn't apply here," says NASA/Marshall's Dr. Jerry Fishman, one of the workshop's organizers. "These are dedicated, well-prepared and knowledgeable astronomers who use very sophisticated equipment -- often comparable to professional observatories. Many of them are able to contribute astronomical data used in forefront astronomical research."
Monitoring fireballs from gamma-ray bursts and tracking the light curves of variable stars are two areas where amateur data can make an impact, says Fishman. The workshop will touch on those topics and more, ranging from gamma-ray explosions at the edge of the universe to cosmic rays here in the solar system. There will be a special session entitled "Rapid Observations of GRBs by Amateurs" prompted in part by the recent detections of gamma-ray burst afterglows by amateurs. The three-day meeting will conclude on Saturday, April 15 with a lecture by Astronaut Dr. John Grunsfield entitled "The 1999 HST Servicing Mission and Remarks on High Energy Astrophysics."
The Invisible, Violent Heavens
High energy astrophysics is the study of the most violent events
in the universe. Colliding neutron stars, gamma-ray bursts (GRBs),
swirling accretion disks around black holes -- these are just
a few of the cosmic wonders visible in the x-ray and gamma-ray
regions of the electromagnetic spectrum. Unfortunately, the short
wavelengths where these events shine brightest are inaccessible
from Earth because our atmosphere filters out most forms of high-energy
radiation. (This is a real nuisance for gamma-ray astronomers,
but a good thing for life on our planet!) To study these objects,
astronomers use ultraviolet, x-ray, and gamma-ray detectors on
Earth-orbiting satellites. 
Satellite-based astronomy was
once the exclusive realm of professionals, but that's slowly
changing.
"Amateurs have been helping scientists with satellite-based
research in variable stars since 1975," says Mattei. "For
example, when the Rossi X-ray Timing Explorer and the Extreme
Ultraviolet Explorer (both are orbiting observatories) were scheduled
to observe the cataclysmic variable star, SS Cygni, the AAVSO
was asked to help. Our members around the world kept a vigil
and when the star flared at optical wavelengths we immediately
called our professional colleagues." Thanks to the rapid
alert, professional astronomers were able to point their satellites
at SS Cygni while it was flaring and monitor the enigmatic star
at many wavelengths for the first time.
"In this particular case everything worked! Optical,
x-ray, extreme ultraviolet-- we got it all."
This summer scientists will try to observe another outburst from
SS Cygni using NASA's newest Great Observatory, the Chandra x-ray
telescope. Once again the AAVSO will be called upon to alert
professionals that SS Cygni is erupting, says Mattei.
Another Glowing Accomplishment....
Performing a feat once reserved for trained
professionals, amateurs have lately shown that they too can photograph
the faint optical afterglows of distant gamma-ray bursts. The
most recent instance was in early
March when an amateur astronomy group in Buffalo, NY, recorded
the fading fireball from a powerful GRB using a modest 14"
telescope and a home-built CCD camera. In January 1999, another
amateur used a 24" telescope in New Mexico to record the
afterglow from a gamma-ray burst located near the edge of the
observable Universe.
Right: Nestled 7 arc seconds from a 17th magnitude foreground
star, the 20th magnitude afterglow of GRB 000301C is circled
in this CCD image from the US Naval Observatory 1m telescope
in Flagstaff, AZ. Credit: Arne Henden.The optical afterglow
was first detected by the Nordic Optical Telescope in La Palma,
Spain and later recorded by amateur astronomers in Buffalo, NY.
[full story]
Theorists believe that studying gamma-ray bursts at optical wavelengths
might help unravel one of the biggest mysteries in modern astronomy:
what causes these powerful gamma-ray explosions? Since astronomers
detected the first optical counterpart of a gamma-ray burst in
1997, they have vigorously pursued the afterglows using some
of the most powerful telescopes including Hubble, Keck, and Palomar.
Powerful telescopes are important for monitoring afterglows because
they fade quickly, usually dimming to 19th magnitude or fainter
just a few hours after the onset of the explosion. Advances in
CCD technology are now bringing these faint fireballs within
reach of dedicated amateur observatories. The afterglow recorded
by amateurs in March, for instance, was 20th magnitude. Astronomy
club observatories still can't record the spectra required to
measure redshift-based distances to afterglows and they probably
never will. The objects are simply too faint for spectroscopy.
Redshifts will remain the province of Hubble and Keck for the
foreseeable future.
Nevertheless, amateurs maintain one important advantage over
their professional counterparts -- telescope time. Telescopes
like Hubble and Keck are heavily oversubscribed. These behemoths
simply can't turn to look at every single gamma-ray burst that
comes along (GRBs are detected once or twice a day by Earth-orbiting
satellites). With little competition for telescope time, amateur
observatories are much more flexible. Eventually a global network
of amateurs might monitor GRB afterglows nearly around the clock,
a feat no single professional observatory can match.
"Measuring
the optical light curves of gamma-ray bursts would be a very
important contribution to astrophysics and there seems to be
no question -- they [the amateurs] can do it." says Dr.
Marshall Joy, an x-ray astronomer at the NASA/Marshall Space
Flight Center who will deliver a lecture on Future Observations
in X-ray Astronomy.
Left: Using graphics and data from NASA's Compton Gamma Ray Observatory, this animation illustrates one of the most exciting mysteries of modern astrophysics, gamma-ray bursts. [more information from the NASA/Goddard Astronomy Picture of the Day]
In fact, amateur observations of gamma-ray bursts seem so
promising that the organizers have scheduled a special session
of the workshop on Rapid Observations of GRBs by Amateurs.
"The most important thing we're doing in this workshop is
bringing interested members of the public into the scientific
enterprise and making them a valuable part of it," concluded
Joy. "These people are going to be the true ambassadors
of high-energy astrophysics."
Stay tuned to Science@NASA for more news from the High Energy
Workshop for Amateur Astronomers, held April 12 - 14 near the
NASA/Marshall Space Flight Center in Huntsville, AL.
The MSFC-AAVSO High Energy Astronomy Workshop will be held
in conjunction with the 89th Meeting of the American Association
of Variable Star Observers (AAVSO). This meeting will be held
the day after the Workshop, at the same venue (The Huntsville
Marriott).
Preliminary
Schedule of Speakers Wednesday, April 12
Thursday, April 13
Friday, April 14
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Sign-up for the AAVSO Gamma-ray Burst Network -- although this page says there is a Dec. 1, 1999 deadline, you can still register!
American Association of Variable Star Observers -- home page, from the Marshall home page