TITLE:   GCN CIRCULAR
NUMBER:  7486
SUBJECT: GRB 080319B: Gemini-South photometry
DATE:    08/03/20 14:26:36 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, J. S. Bloom (UC Berkeley) and H.-W. Chen (U Chicago) report:

On the night of 2008-03-20 (UT) we observed the optical afterglow of GRB 
080319B (GCN 7427, Racusin et al.) with Gemini-South + GMOS in g, r, i, 
and z filters (4x180s in each filter).  The source is well-detected in 
all bands.  Magnitudes, calibrated to SDSS DR6, are:

UTstart  UTend    t(hr)  filt mag   err
06:52:17 07:10:19 24.808  g   20.95 0.09
07:11:19 07:26:11 25.099  r   20.55 0.03
07:27:10 07:42:04 25.363  i   20.40 0.05
07:43:04 07:57:55 25.686  z   20.32 0.03

We thank the observing staff for performing these observations.