TITLE:   GCN CIRCULAR
NUMBER:  31383
SUBJECT: GRB 220101A: LCO Continued Optical Observations
DATE:    22/01/04 10:40:05 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 220101A (Tohuvavohu, et al., GCN 31347) for a second time with the LCO 1-m Sinistro instrument at the McDonald Observatory, Texas, USA site, on January 4, from 03:14 to 03:35 UT (corresponding to 69.70 to 70.05 hours from the GRB trigger time) with the Bessel R and I filters.

We performed a series of 2x400s exposures in R and I bands. We detect the source at the UVOT detection coordinates and other optical observations (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu et al., GCN 31353; Hentunen et al., GCN 31356;
Perley et al., GCN 31357; de Ugarte Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN 31361; Tomasella et al., GCN 31363; Mao et al., GCN 31364; Noschese et al., GCN 31366; Mao et al., GCN 31368; Guelbenzu, et al., GCN 31370; Strausbaugh et al., GCN 31371, D'Avanzo et al., 31373) in both bands. The following magnitudes are calculated using the USNO-B.1 catalog as reference:

R=20.95+/-0.21
I=19.09+/-0.25

These magnitudes are not corrected for galactic extinction.

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