[vsnet-grb-info 4119] GRB 061217: ROTSE-III Optical Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5927
SUBJECT: GRB 061217: ROTSE-III Optical Limits
DATE:    06/12/17 04:34:39 GMT
FROM:    Brad Schaefer at LSU  <schaefer at grb.phys.lsu.edu>

B. E. Schaefer (Louisiana State) reports on behalf of the ROTSE 
collaboration:

ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe, 
Turkey, responded to GRB 061217 (Swift trigger 251634), producing images 
beginning 6.3 s after the GCN notice time. An automated response took the 
first image at 03:40:26.3 UT, 18.1 s after the burst, under excellent 
conditions. We took 10 5-sec, 10 20-sec and 20 60-sec eposures. These 
unfiltered images are calibrated relative to USNO A2.0 (R).  The last few 
images have substantial background from twilight, and so our imaging has 
now stopped in Turkey.

Comparison to the DSS (second epoch) reveals no new sources within the 
3-sigma error circle, for both single images and coadding into sets of 10; 
the field is not crowded. Individual images have limiting magnitudes 
ranging from 15.3-16.9; we set the following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
03:40:26.3   03:40:31.3         5     15.3           18.1       N
03:40:26.3   03:42:34.5       128     17.2           18.1       Y
03:58:53.0   04:10:09.5       676     17.3         1124.8       Y