TITLE:   GCN CIRCULAR
NUMBER:  31214
SUBJECT: GRB 211211A: LCO Optical Observations
DATE:    21/12/12 12:50:00 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh@uvi.edu>

R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:

We observed Swift GRB 211211A (D'Ai et al., GCN 31202) with the LCO 1-m Sinistro instrument at the Teide Observatory, Tenerife site, on December 12, from 05:57 to 06:33 UT (corresponding to 16.8 to 17.4 hours from the GRB trigger time) with the Bessel R and I filters.

We performed a series of 3x400s exposures in R and I bands. We detect a source in both R-band and I-band that is consistent with the Swift Enhanced XRT coordinates (Osborne, et al., GCN 31212) and the optical observations by KAIT (Zheng et al., GCN 31203) and Nanshan/NEXT (Jiang et al., GCN 31213); there appears to be fading in the R band compared to those earlier observations. The following magnitudes are calculated using the USNO-B.1 catalog as reference:

R=20.83+/-0.09

I=21.49+/-0.25

These magnitudes are not corrected for galactic extinction.

R.S. is funded by NSF AST grant #1831682