The Science we are Supporting

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