[vsnet-grb-info 3532] GRB 060729: ROTSE-III Detection of Optical Counterpart

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5366
SUBJECT: GRB 060729: ROTSE-III Detection of Optical Counterpart
DATE:    06/07/29 20:49:33 GMT
FROM:    Robert Quimby at U of Texas/ROTSE  <quimby at astro.as.utexas.edu>

R. Quimby (U Texas), H. Swan (U Mich), W. Rujopakarn (U Mich), and
D.A. Smith (Guilford), report on behalf of the ROTSE collaboration:

ROTSE-IIIa, located at the Siding Spring Observatory, Australia,
responded to Swift trigger 221755 (GRB 060729; Grupe et al. GCN
5365). The first image was taken at 19:13:33.5 UT, 64.3 s after the
burst (8.5 s after the GCN notice time). We detect a source coincident
with the UVOT position (GCN 5365). In a 5-second image beginning at
19:14:02.1 and coincident with the second, larger peak in the BAT
light curve, the object is approximately 15.5 magnitude (unfiltered;
calibrated against the USNO A2.0), while a co-addition of our first 10
5-second images shows the object at approximately 16.6 magnitude.
Images taken over the next 30 minutes do not show significant
evolution, and have a mean magnitude of 16.5.