[vsnet-grb-info 9599] GRB 100807A: ROTSE-III Optical Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11068
SUBJECT: GRB 100807A: ROTSE-III Optical Limits
DATE:    10/08/07 09:40:30 GMT
FROM:    Heather Flewelling at IfA/Hawaii  <flewelling.heather at gmail.com>

GRB 100807A: ROTSE-III Optical Limits

W. Rujopakarn (Steward), H. Flewelling (IfA/Hawaii), B. E. Schaefer
(Louisiana State), W. Zheng (U Mich), and S. B. Pandey (U Mich), report on
behalf of the ROTSE collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 100807A
(Swift trigger 431128; Grupe et al., GCN 11067), producing images beginning
5.2 s after the GCN notice time. An automated response took the first image
at 09:13:35.2 UT, 21.6 s after the burst, and during the gamma-ray emission,
under fair conditions. We took 10 5-sec and 10 20-sec exposures. These
unfiltered images are calibrated relative to USNO A2.0 (R). Imaging is on
going.

Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle or the XRT error circle, for both single
images and coadding into sets of 10. Individual images have limiting
magnitudes ranging from 15.9-17.2; we set the following specific limits.

start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
09:13:35.2 09:13:40.2 5 16.2 21.6 N
09:13:35.2 09:14:42.2 67 16.7 21.6 Y
09:14:55.2 09:19:37.9 282 18.1 101.6 Y