GCN Circular 9778
Subject
GRB 090812: RAPTOR detections during the burst
Event
Date
2009-08-12T17:15:03Z (16 years ago)
From
James Wren at LANL <jwren@nis.lanl.gov>
J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis, B. Norman
of Los Alamos National Laboratory report:
The RAPTOR telescope system responded to Swift trigger
359711 (Stamatikos et al., GCN 9768) under good observing conditions.
Our narrow-field instruments began observing the location at
06:02:32.9 UTC, 24.0 s after the Swift trigger (7.0 s after
receipt of GCN message). We obtained simultaneous observations
during the gamma-ray emitting interval in Cousins V, R, and I
bands as well as unfiltered data. We detect the optical
counterpart in all color bands. Initial analysis of our unfiltered
data calibrated to the USNO-B1 R-band revals the counterpart
brightening until ~T=70s after the trigger and then beginning a
steady decline. The following table gives selected observations,
not corrected for extinction, from this event. Further analysis
of the multi-color data is underway.
t-mid(s) exp(s) mag mag-err
--------------------------------------------
26.48 5.0 15.98 0.18
46.08 5.0 15.39 0.11
73.55 5.0 14.84 0.07
91.71 5.0 15.13 0.09
101.21 5.0 15.25 0.10
141.62 10.0 15.63 0.10