[vsnet-grb-info 2333] GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction

[GCN Circulars]

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  <grr at space.mit.edu>

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.