GCN Circular 9478
Subject
GRB 090530: Early RAPTOR Optical Observations
Date
2009-06-02T00:37:08Z (15 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
353567 (Cannizzo et al., GCN 9438) under fair observing conditions.
Our narrow-field instruments began observing the location at
03:18:37.96 UTC, 19.6 s after the Swift trigger. We detect the
optical counterpart initially reported by Cannizzo et al. (GCN 9438)
and Flewelling et al. (GCN 9439). Our first image at T+22.1 seconds
shows the counterpart at R~17.1. It appears to brighten over the
next minute reaching a peak near R~16.3 and then begins fading in
the manner described by Schady et al. (GCN 9450) and Rossi et al.
(GCN 9458). Our unfiltered images were calibrated against the
USNO-B1 R-band. The following table gives selected observations,
not corrected for extinction, from this event.
t-mid(s) exp(s) mag mag-err
--------------------------------------------
22.08 5.0 17.13 0.25
57.90 5.0 16.30 0.10
84.50 5.0 16.60 0.13
133.21 10.0 16.87 0.11
414.65 30.0 17.31 0.09