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GCN Circular 5539

GRB 060906: Early RAPTOR optical limits
2006-09-06T22:01:25Z (18 years ago)
James Wren at LANL <>
J. Wren, W.T. Vestrand, P.R. Wozniak, R. White, S. Evans, and
J. Pergande of Los Alamos National Laboratory report:
The RAPTOR array of telescopes autonomously responded to Swift
trigger 228316.  Conditions were cloudy at our primary telescope
site but our wide-field RAPTOR-B small telescope array, located
at our secondary site, imaged the event under clear conditions.
Imaging began at 08:34:12.53 UTC (86.0 s after the trigger, 5.8 s
after receipt).  We do not detect the counterpart seen by the Swift
XRT (Racusin et al. GCN 5528) and P60 (Cenko et al. GCN 5529).
The initial unfiltered 5 s exposure yields a 3-sigma limiting
magnitude at the counterpart location of R=15.2 when calibrated
against the GSC 1.1 R-band.  This limit has not been corrected
for foreground galactic extinction.
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