TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3199
SUBJECT: GRB 050408: Magellan astrometry and photometry
DATE:    05/04/09 02:27:11 GMT
FROM:    Josh Bloom at Harvard/CFA  <jbloom@cfa.harvard.edu>

H.- W. Chen (MIT), Paul J. Green (CfA), J. S. Bloom (UCB), & J. X.
Prochaska (UCSC)  report on behalf of the GRAASP collaboration:

"We began imaging the position of GRB050408 at 00:12, April 9 (UT), using
IMACS on the Magellan/Baade telescope in the R and I bands.  The afterglow
candidate reported by de Ugarte Postigo et al. (GCN #3193) is detected in
both bandpasses.  Based on a comparison with objects found in the 2MASS
catalog, we measured the coordinates of the afterglow as RA(J2000)=
12:02:17.328 and Dec(J2000)=+10:51:09.47 with an error of 250 mas in each
coordinate.  We also measure the afterglow brightness to be R = 21.7 +/-
0.1 mag and I = 21.4 +/- 0.1 mag with R-I=0.3, 7h50m after the initial
trigger."

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