{
  "bibcode": "2021GCN.31321....1S",
  "body": "R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:\n\nWe observed Swift GRB 211227A (Beardmore, et al., GCN 31316) with the LCO 1-m Sinistro instrument at the Teide, Tenerife site, on December 28, from 00:39 to 01:11 UT (corresponding to 1.12 to 1.48 hours from the GRB trigger time) with the Bessel R and I filters.\n\nWe performed a series of 4x240s exposures in R and I bands. We detect no sources within the Swift XRT detection region (Beardmore, et al., GCN 31316) in either band. The following upper limits are calculated using the USNO-B.1 catalog as reference:\n\nR>22.81\nI>22.42\n\nWe do note the presence of a faint uncatalogued source just outside the XRT region at RA, DEC = (132.1449185, -2.7343489) at the following magnitudes, calculated with respect to the USNO-B.1 catalog:\n\nR=21.79+/-0.20\nI=22.13+/-0.24\n\nWe recommend continued monitoring of this source to determine if it is fading.  These magnitudes are not corrected for galactic extinction.\n\nR.S. is funded by NSF AST grant #1831682",
  "circularId": 31321,
  "createdOn": 1640659919000,
  "email": "robert.strausbaugh@uvi.edu",
  "subject": "GRB 211227A: LCO Optical Observations",
  "submitter": "Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh@uvi.edu>",
  "eventId": "GRB 211227A"
}