TITLE:   GCN CIRCULAR
NUMBER:  31481
SUBJECT: GRB 220117A: LCO Optical Observations
DATE:    22/01/18 13:39:22 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 220117A (Melandri et al., GCN 31466) with the LCO 1-m Sinistro instrument at the Cerro Tololo Interamerican Observatory, Chile site, on January 18, from 01:16 to 01:33 UT (corresponding to 6.97 to 7.25 hours from the GRB trigger time) with the Bessel R and I filters.

We performed a series of 3x320s exposures in I band and 1x152s in R band (the planned observations in R were interrupted). We detect the source at the XRT enhanced coordinates (Beardmore et al., GCN 31472) and VLT observations (Palmerio et al., GCN 31480) in I band, but not R band. The following magnitudes and upper limits are calculated using the USNO-B.1 catalog as reference:

R>19.14
I=20.64+/-0.30

These magnitudes are not corrected for galactic extinction.

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