[vsnet-grb-info 3754] GRB 060923: Early Super-LOTIS Observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5588
SUBJECT: GRB 060923: Early Super-LOTIS Observations
DATE:    06/09/23 08:42:34 GMT
FROM:    Grant Williams at Steward Observatory  <ggwilli at mmto.org>

G. G. Williams (MMTO) and P. A. Milne (Steward Observatory), on behalf of 
the Super-LOTIS Collaboration, report:

The robotic 0.6-m Super-LOTIS telescope began observing the error box of 
GRB 060923 (Swift Trigger 230662, Stamatikos et al. GCN 5583) at 
05:12:56.1 UT, 41.1 seconds after the trigger.  Our initial observations 
include 5 x 10s exposures, 5 x 20s exposures, and 30 x 60s exposures, all 
in the R-band.  The observations began at a high airmass of 2.92.

We do not detect any variable sources or afterglow candidates within the 
XRT error box in our earliest exposure or in the sum of our first five 
exposures to the following 3-sigma limiting magnitudes determined from 
nearby USNO-B1.0 stars:

t_start (UT)	exp t (s)	t_start-t_0 (s)	Limit
--------------------------------------------------------
05:12:56.1	10.0 		41.1 		R > 16.6 +/- 0.15
05:12:56.1      5 x 10.0        41.1            R > 18.3 +/- 0.15

The errors are dominated by scatter in the USNO-B1.0 stars.