When asked about the kinds of science being supported by the AAVSO and it's GRB Transient Search community, Arne Henden offered the following insight:
1) Few afterglows have been seen. We need a larger sample, and
HETE should double the known afterglows in its first year. The
ones we have seen have different power-law decays, no seeming
correlation between gamma-ray brightness, afterglow brightness,
and redshift. Correlations may be found with the larger sample.
The hope is that GRBs will eventually become a 'standard candle'
and can calibrate distances to the edge of the universe.
2) There should be several classes of gamma-ray bursts. Even in
the BATSE catalog, there are short bursts and long bursts, with
perhaps an intermediate class. Only long bursts have detected
afterglows so far. Why? Again, a large sample will help. Or
perhaps the short bursts have faint afterglows, so early detection
will help.
3) There are differences in the models depending on beaming or
isotropic radiation. Early detection and photometry can distinguish
between these.
4) The models suggest the prompt radiation comes from a different
mechanism than the afterglow. Only one burst has had its prompt
radiation detected. HETE should allow telescopes to get on
a burst quickly enough to follow the prompt decay. Here again,
professionals can't act quickly enough to catch many of these
prompt decays, but amateurs can (especially with their longitudinal
spread).
5) Quick determination of coordinates and approximate magnitudes
give a 'heads-up' for the professionals so that they can train
their telescopes and get spectroscopic, photometric and polarization
data on the bursts. Their narrow fields of view require the
good coordinates, and the early photometry tells them whether it
is worth going after a given burst. For example, bright afterglows
can be observed spectroscopically with meter-class telescopes if
caught in the first hour or so, thereby freeing up the big 'scopes
to follow fainter bursts.
6) Early detection means photometry when the afterglow is 5-10 magnitudes
brighter than its 24hr value. This means you can work on afterglows
that suffer a fair amount of extinction, whether in our galaxy or
in the local medium of the source. This again increases the sample size.
7) Early detection means amateurs can contribute UBVRI calibrated photometry,
again freeing up the professionals from having to do photometry in addition
to their other instrument investigations. Amateurs can often do higher
time resolution work than the bigger chips (longer readout) of the
professional telescopes, again giving more detailed information of the
early time history of a burst.
8) Professionals cannot follow every burst; GRB research is just one program
at most observatories and cannot take every minute of telescope time.
So amateur observations will help increase the sample size.
There are a dozen other reasons, but this is a good start.
Arne