Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 13969

GRB 121117A: ROTSE-III Optical Limits
2012-11-17T13:05:41Z (12 years ago)
Weikang Zheng at U.of Michigan <>
W. Zheng (U Mich), report on behalf of the ROTSE collaboration: 


ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 121117A
(Swift trigger 538696; Cummings et al., GCN 13967), producing images
beginning 9.1 s after the GCN notice time. An automated response took the
first image at 08:51:21.1 UT, 24.1 s after the burst, under fair conditions.
We took 10 5-sec, 10 20-sec and 20 60-sec exposures. 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 Swift/BAT error circle. Individual images have limiting magnitudes
ranging from 14.9-16.4; we set the following specific limits. 


start UT       end UT      t_exp(s)   mlim   Coadd?


08:50:57.0   08:55:57.0         5     15.0     N 

08:51:32.0   08:51:37.0         5     15.0     N 

08:51:43.0   08:51:48.0         5     15.4     N 

08:51:55.0   08:52:00.0         5     15.2     N 

08:52:07.0   08:52:12.0         5     15.2     N 

08:50:57.0   08:53:04.0        50     16.8     Y 

08:53:18.0   08:57:59.0       200     17.2     Y
Looking for U.S. government information and services? Visit