Aaon Price of AAVSO submitted this estimate of GCN volume to the list server for comment.
Localizations:
Hete: 2 per week
Other: .5 per week (current average since Compton fell)
So, about 10 localizations per month. Half will be in your hemisphere, so
about 5 per month? Half of that will be lost to the moon, so about 2.5
good GRBs per month will be the average. Gives us one week between GRBs to
rest up!
Alas, the satellite is going to hug the equator so it doesnt look like we
will get to eaves drop on its transmissions. :)
Aaron Price, Technical Assistant, UNIX, CGI.
American Association of Variable Star Observers
Arne Hendon responded as follows:
Actually, it is a little worse than that since you haven't included
the sun (it is up ~1/2 of the time, after all) and weather. The moon
is a little less of a problem, especially for amateurs, since you
will be looking at the bright part of the burst. On the other hand,
us pros get to look on more than one night per burst, so we will be
even busier than the amateurs!
What I would dearly love to see is some amateur in a good site
who is willing to do the UBVRI photometric calibration of each field.
That takes many hours of my time per burst currently, and I see it
just getting worse after HETE.
Arne
Arne went on to write:
Aaron asked off-line how many alert notices should be
received from HETE2. Now, I'm not associated with the
spacecraft and am just repeating things I've gleaned from
various contacts, so don't believe everything I say.
The gamma-ray detectors cover a large fraction of the
sky, so I'd expect about the same number of bursts as
for BATSE (maybe one every day or so). No directional
information; you get that from either the Xray detectors
or from time-of-delay triangularization ala IPN.
The Xray detectors cover ~1/4 of the sky at low
resolution (say 10arcmin localizations), and ~1/8 of
the sky at high resolution (say 30arcsec localizations).
So the Xray localizations will occur once/week or so.
The Xray localizations occur within seconds after a burst
and are generated on-satellite. The "alert" notice does
not contain localization info, but occurs as soon as a burst
is identified. Then several "flight" notices occur as the
spacecraft analyzes the burst and calculates increasingly
more accurate positions. The 15mins-2hr delay
Aaron mentioned are more sophisticated localization analyses
that are still automated, but groundbased. Even more improved
positions are possible with human intervention, but hours
after a burst. So Aaron, you will see a flood of GCN messages
for every well-detected burst.
As for a photometry table: sure, if you access the NOFS
web site, you get a finding chart, jpeg images of the field,
and astrometric/photometric data for all stars. Why not
include all of these on the AAVSO web site? The chart and
table will be a *very* small increment to the jpeg images.
The more you can offload from the NOFS site, the better.
Arne
