[vsnet-grb-info 5813] GRB 080319B: RAPTOR observations of a naked eye burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7464
SUBJECT: GRB 080319B: RAPTOR observations of a naked eye burst
DATE:    08/03/19 22:09:52 GMT
FROM:    Przemyslaw R. Wozniak at LANL  <wozniak at lanl.gov>

P. Wozniak, W.T. Vestrand, J. Wren, and H. Davis
(Los Alamos National Laboratory)

The RAPTOR sky monitoring system began observing the location
of GRB 080319B more than an hour before the Swift BAT trigger
306757 (Racusin et al., GCN 7427). The first exposure with detectable
optical emission started ~2 seconds after the trigger at 06:12:50.9 UT.
A peak brightness of 5.6 mag was recorded in time interval from
06:13:21.2 to 06:13:31.2 UT, before the end of the gamma-ray emission.
Using the redshift z=0.937 from Vreeswijk et al. (GCN 7444) the
estimated luminosity of GRB 080319B exceeds that of GRB 990123.

Our response arrays RAPTOR-P and T began imaging at 06:14:24.3 UT
following the XRT localization trigger that interrupted the ongoing
follow-up measurements of GRB 080319A. The OT is detected by both
response instruments including all channels (V,R,I,clear) of the
simultaneous multicolor imager RAPTOR-T.