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--
Arto Oksanen                       mailto:arto.oksanen_at_jklsirius.fi
Jyvaskylan Sirius ry, Kyllikinkatu 1, FIN-40100 Jyväskylä,  Finland 
Tel. +358-14-4157852, Mobile: +358-40-5659438, Fax: +358-14-4157803
Nyrola Observatory    http://www.ursa.fi/sirius/nytt/nytt_info.html 

-----Original Message-----
From: Arne Henden [mailto:aah_at_nofs.navy.mil] 
Sent: 2. huhtikuuta 2003 20:53
To: agrb
Subject: ÄAAVSO-GRBÅ grb030329, summary to date


   The burst was detected by HETE (GCN 1997) and was considered a long,
extremely bright GRB.  The best localization was from the SXC instrument,
giving a 90% confidence circle that was 2arcmin in radius and centered at
     10:44:50 +21:30:54 J2000
The burst occurred at 11:37:14.67 UT, and was reported at 12:50:24 UT, a
delay of 73minutes due to the necessity of a ground analysis for this
particular burst.  This alert was too late for any U.S. observation.
   Peterson and Price (GCN 1985), observing from Siding Springs, found an
optical transient at 12th magnitude in R and reported it at 13:27UT.  At
13:43UT,  the RIKEN group confirmed this OT. The coordinates of this
transient were given in GCN 1987 as
   RA: 10:44:50.0   Dec: 21:31:17.8   (J2000)
A contemporaneous CONCAM observation (Ofek et al., GCN 2031) gives a prompt
emission limit of magnitude ~ 3.5; this is quite bright and perhaps can be
extended downward with careful reduction.  It would seem the on-board HETE
optical camera should give a fainter limit as well.
   Numerous other groups then started reporting photometry as the field
became observable at their site.  Finally, a decent redshift was reported by
Greiner et al. (GCN 2020) as z=0.168; the closest GRB except for GRB980425
(SN1998bw), which is most likely why the afterglow is so bright.
Observations were made in the X-ray region by RXTE (Marshall et al., GCN
1996, 2052), who indicated that this was one of the brightest afterglows
ever detected by RXTE.  J-band data was given by Lamb, et al. (GCN 2040);
this data shows the burst to be relatively bright in the near-IR, especially
since it is quite blue in the visible wavelengths. Radio observations were
given by Berger, et al. (GCN 2014) and Pooley (GCN2043) and also indicated
that this was the brightest radio afterglow ever observed.
   One of the more interesting aspects of this burst were the visual
observations from Henriksson and Tuukkanen (GCN 2010), two Finnish
observers, who saw the OT while it was still around V=14.2.
   First-day reports indicated a bump in the general decline, similar to
GRB021004.  Likewise, there were reports of light curve breaks, etc.,
showing that the light curve was not smooth, but had bumps and wiggles.  It
will take a few days before a clean light curve is available since few
people used common comparison stars.
   There have been reports from many AAVSO members; good going! These have
resulted in two GCNs so far: 2058 and 2071. The current light curve shows
general fading, reaching V=17.5 last night, but with many bumps and wiggles.
It may rebrighten, but in any case seems to be flattening out.  If you can
get decent statistics at R=17 with ~1hr exposures, I would continue to
observe this OT, concentrating on Rc.  I calibrated the field (GCN2023) and
recommend everyone use that calibration since only zeropoint shifts will be
necessary.  You should *not* use USNO-A for photometric calibration. Arne

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