GCN Circular 2066

J. Tober, E. Hoverstein, K. Chiu, K. Glazebrook

We have observed the optical afterglow of GRB 030329 with the 20in 
Morris W. Offit telescope
of the Maryland Space Grant Consortium Observatory. The telescope is 
located in
downtown Baltimore, Maryland and the observations were made with a 
student built
CCD camera on the night of March 31st / morning of April 1st with an 
R-band filter.

Aperture photometry was made with APPHOT in a 20 arcsec diameter 
aperture with
errors empirically estimated from the background noise. The photometry 
is
computed by assuming the USNO reference star at RA 10 44 42.01 DEC +21 
32 31.8
has constant magnitude R=16.2 but counts were consistent from run to run
indicating near-photometric conditions.

The GRB appeared to brighten suddenly between ~02:30 and ~03:30 by 0.5 
mags and then fade
slowly for the next few hours.

Table 1. R-band Observations. Magnitudes and errors. Times (t) are in 
minutes from 02:33 UT on
April 01, 2003 and refer to the middle of stacked sequences of ~25 
minute exposures.

   t   Star1         Star3        Star5         GRB

   0   13.749 0.007 16.257 0.069 16.904 0.126  17.457  0.207

  52   13.696 0.007 16.104 0.064 16.617 0.108  16.844  0.130   *** Jump ?

117   13.778 0.007 16.275 0.069 16.931 0.128  17.056  0.141

165   13.826 0.007 16.198 0.062 16.884 0.108  17.169  0.154

209   13.637 0.008 16.076 0.070 16.538 0.104  16.940  0.153

The error on the reference star was +/- 0.07 which should be added in 
quadrature to
the above table.

(Note star 1 is off the nominal R=14.00 value which we attribute to 
non-linearity in the CCD)

This photometry is preliminary, further analysis is proceeding. The 
reference stars
are indicated at:

http://mrhanky.pha.jhu.edu/~kgb/GRB030329/grb-circ-finder.jpg

A plot of the light curve is available from:

http://mrhanky.pha.jhu.edu/~kgb/GRB030329/grbplot2.ps

The  Maryland Space Grant Consortium Observatory is supported by NASA's 
National
Space Grant College and Fellowship Program. Further information is 
available at:
http://henry.pha.jhu.edu/msgc/observatory.html