TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5133
SUBJECT: GRB 060515: ROTSE-III Optical Limits 
DATE:    06/05/15 02:55:35 GMT
FROM:    Eli Rykoff at U of Michigan/ROTSE  <erykoff@umich.edu>

E.S. Rykoff (U Mich), W. Rujopakarn (U Mich), B. E. Schaefer (Louisiana 
State), S.A. Yost (U Mich), report on behalf of the ROTSE collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 
060515 (Swift trigger 210084, GCN 5132), producing images beginning 6.8 
s after the GCN notice time. An automated response took the first image 
at 02:28:50.7 UT, 57.8 s after the burst, under windy conditions. We 
took 10 5-sec and 10 20-sec exposures before clouds came in. These 
unfiltered images are calibrated relative to USNO A2.0 (R).

Comparison to the DSS (second epoch) reveals no new sources within the 
3-sigma BAT error circle, for both single images and coadding into sets 
of 10. Individual images have limiting magnitudes ranging from 
13.9-14.9; we set the following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
02:28:50.7   02:28:55.7         5     14.2           57.8       N
02:28:50.7   02:29:57.9        67     15.6           57.8       Y