TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4170 SUBJECT: GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction DATE: 05/10/28 01:19:53 GMT FROM: George Ricker at MIT GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction N. R. Butler (UC-Berkeley), G. R. Ricker (MIT), D. Q. Lamb(U. Chicago), D. N. Burrows (PSU), J. Racusin (PSU), and N. Gehrels (GSFC) report: In our calculation (Butler et al. GCN 4165) of the extinction of the optical and NIR afterglow of GRB 051022 in the observer frame implied by the best-fit value of the absorption of the X-ray afterglow measured by the Swift XRT, we did not take into account the transformation between the absorption of the X-ray spectrum as measured in the observer frame and that measured in the rest frame of the host galaxy. Taking this transformation into account, and using the same method as that described in Butler et al. (GCN 4165), we derive the following values for the extinction in magnitudes in the observer frame: A_V = 41.1 +/- 3.4, A_R = 36.7 +/- 3.0, A_I = 30.9 +/- 2.5, A_J = 17.6 +/- 1.5, A_H = 10.8 +/- 0.9, and A_Ks = 6.8 +/- 0.6. These values for the extinction are large enough to account for the failure to detect the afterglow of GRB 051022 in either the optical (Torii GCN 4130; Schaefer GCN 4132; Sonoda et al., GCN 4133; Cenko et al., GCN 4134; Cool GCN 4149; Immler et al., GCN 4155) or the NIR (Castro-Tirado et al., GCN 4143; Berger and Wyatt, GCN 4148: Nysewander et al., GCN 4152; Bloom GCN 4153), provided that most of the dust is not destroyed by the burst and/or its afterglow.