[AAVSO-HEN] GRB 071003: MARGE Observations

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  6841
SUBJECT: GRB 071003: MARGE Observations
DATE:    07/10/03 22:02:30 GMT
FROM:    Heather Swan at U.of Michigan/ROTSE  <hflewell at umich.edu>

H. Swan (U Mich), I. Smith (Rice), W. Rujopakarn (Steward), F. Yuan (U 
Mich), S. Yost (College of St. Benedict), C. Akerlof (U Mich),  M. 
Skinner (Boeing), R. Russell (Aerospace Corporation) report on behalf of 
the MARGE collaboration:

The AEOS Burst Camera (ABC) on the AEOS telescope, located at the Maui 
Space Surveillance System on Haleakala, observed the fading counterpart 
to GRB071003 (Swift trigger 292934 (P. Schady et al. GCN 6837)). The 
images are unfiltered 10s exposures which started ~9 minutes after the 
trigger and ended ~ 3 hours later.

We detect the OT first identified by W. Li (GCN 6838). A preliminary 
analysis gives a magnitude of approximately 16.04+/-0.01 at 7:40:55 UT. 
We calibrated the OT to the USNO-B1.0 R2 band magnitudes of several 
nearby stars. We find that the early ABC data fades as a power law decay 
with  index  ~1.9.

We note that the lightcurve has a flatter decay index after about 2000 
seconds. This may be partially due to contamination from the nearby 
10.79 mag star that will be resolved by more careful analysis. It is 
possible that the OT is still visible (< 22nd mag).

Further observations are planned.