TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1159 SUBJECT: Correction: GCN1157 (GRB 011121) DATE: 01/11/24 21:23:49 GMT FROM: Knut Olsen at CTIO The values of the R and I-band extinctions reported in GCN 1157 incorrectly used the ratios of total to selective absorption appropriate for Johnson, rather than Cousins, filters. The correct extinction values are A_R=1.328 and A_I=0.964, rather than A_R = 1.16 and A_I = 0.74. The intrinsic colors are then (V-R) = 0.53 and (V-I) = 0.75. Many thanks to Kris Stanek for pointing out the mistake. Knut Olsen